Merge branch 'mm-unstable' of https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

author: Mark Brown <broonie@kernel.org> 2026-05-29 17:54:35 +0100
committer: Mark Brown <broonie@kernel.org> 2026-05-29 17:54:35 +0100
commit: 76dc299c2ef007e68114b956abec0bc21777b2d9 (patch)
tree: bdb5e5d56848cfefd24dceeab438743c0804b8e9 /fs
parent: 686a7ac3f6b13a5800282ddd81d80d71f29f75d6 (diff)
parent: 404fb4f38e8f38469dfff4df0205c9d18eeb1f57 (diff)
download: linux-next-history-76dc299c2ef007e68114b956abec0bc21777b2d9.tar.gz
6 files changed, 156 insertions, 2304 deletions
diff --git a/fs/Makefile b/fs/Makefile
index ae1b07f9c6a0c..89a8a9d207d1c 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -27,7 +27,6 @@ obj-y				+= anon_inodes.o
 obj-$(CONFIG_SIGNALFD)		+= signalfd.o
 obj-$(CONFIG_TIMERFD)		+= timerfd.o
 obj-$(CONFIG_EVENTFD)		+= eventfd.o
-obj-$(CONFIG_USERFAULTFD)	+= userfaultfd.o
 obj-$(CONFIG_AIO)               += aio.o
 obj-$(CONFIG_FS_DAX)		+= dax.o
 obj-$(CONFIG_FS_ENCRYPTION)	+= crypto/
diff --git a/fs/btrfs/defrag.c b/fs/btrfs/defrag.c
index 7e2db5d3a4d4c..a8d49d9ca981c 100644
--- a/fs/btrfs/defrag.c
+++ b/fs/btrfs/defrag.c
@@ -860,9 +860,6 @@ again:
 		return folio;
 
 	/*
-	 * Since we can defragment files opened read-only, we can encounter
-	 * transparent huge pages here (see CONFIG_READ_ONLY_THP_FOR_FS).
-	 *
 	 * The IO for such large folios is not fully tested, thus return
 	 * an error to reject such folios unless it's an experimental build.
 	 *
diff --git a/fs/inode.c b/fs/inode.c
index 62c579a0cf7df..11bfb93ef0e69 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -279,9 +279,6 @@ int inode_init_always_gfp(struct super_block *sb, struct inode *inode, gfp_t gfp
 	mapping->flags = 0;
 	mapping->wb_err = 0;
 	atomic_set(&mapping->i_mmap_writable, 0);
-#ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	atomic_set(&mapping->nr_thps, 0);
-#endif
 	mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
 	mapping->writeback_index = 0;
 	init_rwsem(&mapping->invalidate_lock);
diff --git a/fs/open.c b/fs/open.c
index 681d405bc61eb..c321b80027f13 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -968,33 +968,6 @@ static int do_dentry_open(struct file *f,
 	if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT))
 		return -EINVAL;
 
-	/*
-	 * XXX: Huge page cache doesn't support writing yet. Drop all page
-	 * cache for this file before processing writes.
-	 */
-	if (f->f_mode & FMODE_WRITE) {
-		/*
-		 * Depends on full fence from get_write_access() to synchronize
-		 * against collapse_file() regarding i_writecount and nr_thps
-		 * updates. Ensures subsequent insertion of THPs into the page
-		 * cache will fail.
-		 */
-		if (filemap_nr_thps(inode->i_mapping)) {
-			struct address_space *mapping = inode->i_mapping;
-
-			filemap_invalidate_lock(inode->i_mapping);
-			/*
-			 * unmap_mapping_range just need to be called once
-			 * here, because the private pages is not need to be
-			 * unmapped mapping (e.g. data segment of dynamic
-			 * shared libraries here).
-			 */
-			unmap_mapping_range(mapping, 0, 0, 0);
-			truncate_inode_pages(mapping, 0);
-			filemap_invalidate_unlock(inode->i_mapping);
-		}
-	}
-
 	return 0;
 
 cleanup_all:
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 751b9ba160fbf..1e3a15bf46f4e 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -132,6 +132,22 @@ static void release_task_mempolicy(struct proc_maps_private *priv)
 
 #ifdef CONFIG_PER_VMA_LOCK
 
+static inline int lock_ctx_mm(struct proc_maps_locking_ctx *lock_ctx)
+{
+	int ret = mmap_read_lock_killable(lock_ctx->mm);
+
+	if (!ret)
+		lock_ctx->mmap_locked = true;
+
+	return ret;
+}
+
+static inline void unlock_ctx_mm(struct proc_maps_locking_ctx *lock_ctx)
+{
+	mmap_read_unlock(lock_ctx->mm);
+	lock_ctx->mmap_locked = false;
+}
+
 static void reset_lock_ctx(struct proc_maps_locking_ctx *lock_ctx)
 {
 	lock_ctx->locked_vma = NULL;
@@ -146,25 +162,11 @@ static void unlock_ctx_vma(struct proc_maps_locking_ctx *lock_ctx)
 	}
 }
 
-static const struct seq_operations proc_pid_maps_op;
-
 static inline bool lock_vma_range(struct seq_file *m,
 				  struct proc_maps_locking_ctx *lock_ctx)
 {
-	/*
-	 * smaps and numa_maps perform page table walk, therefore require
-	 * mmap_lock but maps can be read with locking just the vma and
-	 * walking the vma tree under rcu read protection.
-	 */
-	if (m->op != &proc_pid_maps_op) {
-		if (mmap_read_lock_killable(lock_ctx->mm))
-			return false;
-
-		lock_ctx->mmap_locked = true;
-	} else {
-		rcu_read_lock();
-		reset_lock_ctx(lock_ctx);
-	}
+	rcu_read_lock();
+	reset_lock_ctx(lock_ctx);
 
 	return true;
 }
@@ -172,7 +174,7 @@ static inline bool lock_vma_range(struct seq_file *m,
 static inline void unlock_vma_range(struct proc_maps_locking_ctx *lock_ctx)
 {
 	if (lock_ctx->mmap_locked) {
-		mmap_read_unlock(lock_ctx->mm);
+		unlock_ctx_mm(lock_ctx);
 	} else {
 		unlock_ctx_vma(lock_ctx);
 		rcu_read_unlock();
@@ -213,17 +215,45 @@ static inline bool fallback_to_mmap_lock(struct proc_maps_private *priv,
 	return true;
 }
 
+static inline void drop_rcu(struct proc_maps_private *priv)
+{
+	if (priv->lock_ctx.mmap_locked)
+		return;
+
+	rcu_read_unlock();
+}
+
+static inline void reacquire_rcu(struct proc_maps_private *priv)
+{
+	if (priv->lock_ctx.mmap_locked)
+		return;
+
+	rcu_read_lock();
+	/* Reinitialize the iterator. */
+	vma_iter_set(&priv->iter, priv->lock_ctx.locked_vma->vm_end);
+}
+
 #else /* CONFIG_PER_VMA_LOCK */
 
+static inline int lock_ctx_mm(struct proc_maps_locking_ctx *lock_ctx)
+{
+	return mmap_read_lock_killable(lock_ctx->mm);
+}
+
+static inline void unlock_ctx_mm(struct proc_maps_locking_ctx *lock_ctx)
+{
+	mmap_read_unlock(lock_ctx->mm);
+}
+
 static inline bool lock_vma_range(struct seq_file *m,
 				  struct proc_maps_locking_ctx *lock_ctx)
 {
-	return mmap_read_lock_killable(lock_ctx->mm) == 0;
+	return lock_ctx_mm(lock_ctx) == 0;
 }
 
 static inline void unlock_vma_range(struct proc_maps_locking_ctx *lock_ctx)
 {
-	mmap_read_unlock(lock_ctx->mm);
+	unlock_ctx_mm(lock_ctx);
 }
 
 static struct vm_area_struct *get_next_vma(struct proc_maps_private *priv,
@@ -238,6 +268,9 @@ static inline bool fallback_to_mmap_lock(struct proc_maps_private *priv,
 	return false;
 }
 
+static inline void drop_rcu(struct proc_maps_private *priv) {}
+static inline void reacquire_rcu(struct proc_maps_private *priv) {}
+
 #endif /* CONFIG_PER_VMA_LOCK */
 
 static struct vm_area_struct *proc_get_vma(struct seq_file *m, loff_t *ppos)
@@ -538,12 +571,10 @@ static int query_vma_setup(struct proc_maps_locking_ctx *lock_ctx)
 
 static void query_vma_teardown(struct proc_maps_locking_ctx *lock_ctx)
 {
-	if (lock_ctx->mmap_locked) {
-		mmap_read_unlock(lock_ctx->mm);
-		lock_ctx->mmap_locked = false;
-	} else {
+	if (lock_ctx->mmap_locked)
+		unlock_ctx_mm(lock_ctx);
+	else
 		unlock_ctx_vma(lock_ctx);
-	}
 }
 
 static struct vm_area_struct *query_vma_find_by_addr(struct proc_maps_locking_ctx *lock_ctx,
@@ -1280,21 +1311,75 @@ static const struct mm_walk_ops smaps_shmem_walk_ops = {
 	.walk_lock		= PGWALK_RDLOCK,
 };
 
+#ifdef CONFIG_PER_VMA_LOCK
+
+static const struct mm_walk_ops smaps_walk_vma_lock_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+	.walk_lock		= PGWALK_VMA_RDLOCK_VERIFY,
+};
+
+static const struct mm_walk_ops smaps_shmem_walk_vma_lock_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+	.pte_hole		= smaps_pte_hole,
+	.walk_lock		= PGWALK_VMA_RDLOCK_VERIFY,
+};
+
+static inline const struct mm_walk_ops *
+get_smaps_walk_ops(struct proc_maps_private *priv)
+{
+	if (priv->lock_ctx.mmap_locked)
+		return &smaps_walk_ops;
+	return &smaps_walk_vma_lock_ops;
+}
+
+static inline const struct mm_walk_ops *
+get_smaps_shmem_walk_ops(struct proc_maps_private *priv)
+{
+	if (priv->lock_ctx.mmap_locked)
+		return  &smaps_shmem_walk_ops;
+	return &smaps_shmem_walk_vma_lock_ops;
+}
+
+#else /* CONFIG_PER_VMA_LOCK */
+
+static inline const struct mm_walk_ops *
+get_smaps_walk_ops(struct proc_maps_private *priv)
+{
+	return &smaps_walk_ops;
+}
+
+static inline const struct mm_walk_ops *
+get_smaps_shmem_walk_ops(struct proc_maps_private *priv)
+{
+	return &smaps_shmem_walk_ops;
+}
+
+#endif /* CONFIG_PER_VMA_LOCK */
+
 /*
  * Gather mem stats from @vma with the indicated beginning
  * address @start, and keep them in @mss.
  *
  * Use vm_start of @vma as the beginning address if @start is 0.
  */
-static void smap_gather_stats(struct vm_area_struct *vma,
-		struct mem_size_stats *mss, unsigned long start)
+static void smap_gather_stats(struct proc_maps_private *priv,
+			      struct vm_area_struct *vma,
+			      struct mem_size_stats *mss, unsigned long start)
 {
-	const struct mm_walk_ops *ops = &smaps_walk_ops;
+	const struct mm_walk_ops *ops = get_smaps_walk_ops(priv);
 
 	/* Invalid start */
 	if (start >= vma->vm_end)
 		return;
 
+	if (vma == get_gate_vma(priv->lock_ctx.mm))
+		return;
+
+	/* Might sleep. Drop RCU read lock but keep the VMA locked. */
+	drop_rcu(priv);
+
 	if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
 		/*
 		 * For shared or readonly shmem mappings we know that all
@@ -1312,15 +1397,16 @@ static void smap_gather_stats(struct vm_area_struct *vma,
 					!(vma->vm_flags & VM_WRITE))) {
 			mss->swap += shmem_swapped;
 		} else {
-			ops = &smaps_shmem_walk_ops;
+			ops = get_smaps_shmem_walk_ops(priv);
 		}
 	}
 
-	/* mmap_lock is held in m_start */
 	if (!start)
 		walk_page_vma(vma, ops, mss);
 	else
 		walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss);
+
+	reacquire_rcu(priv);
 }
 
 #define SEQ_PUT_DEC(str, val) \
@@ -1369,10 +1455,11 @@ static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
 
 static int show_smap(struct seq_file *m, void *v)
 {
+	struct proc_maps_private *priv = m->private;
 	struct vm_area_struct *vma = v;
 	struct mem_size_stats mss = {};
 
-	smap_gather_stats(vma, &mss, 0);
+	smap_gather_stats(priv, vma, &mss, 0);
 
 	show_map_vma(m, vma);
 
@@ -1413,7 +1500,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 		goto out_put_task;
 	}
 
-	ret = mmap_read_lock_killable(mm);
+	ret = lock_ctx_mm(&priv->lock_ctx);
 	if (ret)
 		goto out_put_mm;
 
@@ -1425,7 +1512,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 
 	vma_start = vma->vm_start;
 	do {
-		smap_gather_stats(vma, &mss, 0);
+		smap_gather_stats(priv, vma, &mss, 0);
 		last_vma_end = vma->vm_end;
 
 		/*
@@ -1434,8 +1521,8 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 		 */
 		if (mmap_lock_is_contended(mm)) {
 			vma_iter_invalidate(&vmi);
-			mmap_read_unlock(mm);
-			ret = mmap_read_lock_killable(mm);
+			unlock_ctx_mm(&priv->lock_ctx);
+			ret = lock_ctx_mm(&priv->lock_ctx);
 			if (ret) {
 				release_task_mempolicy(priv);
 				goto out_put_mm;
@@ -1484,14 +1571,14 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 
 			/* Case 1 and 2 above */
 			if (vma->vm_start >= last_vma_end) {
-				smap_gather_stats(vma, &mss, 0);
+				smap_gather_stats(priv, vma, &mss, 0);
 				last_vma_end = vma->vm_end;
 				continue;
 			}
 
 			/* Case 4 above */
 			if (vma->vm_end > last_vma_end) {
-				smap_gather_stats(vma, &mss, last_vma_end);
+				smap_gather_stats(priv, vma, &mss, last_vma_end);
 				last_vma_end = vma->vm_end;
 			}
 		}
@@ -1505,7 +1592,7 @@ empty_set:
 	__show_smap(m, &mss, true);
 
 	release_task_mempolicy(priv);
-	mmap_read_unlock(mm);
+	unlock_ctx_mm(&priv->lock_ctx);
 
 out_put_mm:
 	mmput(mm);
@@ -3291,6 +3378,31 @@ static const struct mm_walk_ops show_numa_ops = {
 	.walk_lock = PGWALK_RDLOCK,
 };
 
+#ifdef CONFIG_PER_VMA_LOCK
+static const struct mm_walk_ops show_numa_vma_lock_ops = {
+	.hugetlb_entry = gather_hugetlb_stats,
+	.pmd_entry = gather_pte_stats,
+	.walk_lock = PGWALK_VMA_RDLOCK_VERIFY,
+};
+
+static inline const struct mm_walk_ops *
+get_show_numa_ops(struct proc_maps_private *priv)
+{
+	if (priv->lock_ctx.mmap_locked)
+		return &show_numa_ops;
+	return &show_numa_vma_lock_ops;
+}
+
+#else /* CONFIG_PER_VMA_LOCK */
+
+static inline const struct mm_walk_ops *
+get_show_numa_ops(struct proc_maps_private *priv)
+{
+	return &show_numa_ops;
+}
+
+#endif /* CONFIG_PER_VMA_LOCK */
+
 /*
  * Display pages allocated per node and memory policy via /proc.
  */
@@ -3335,8 +3447,13 @@ static int show_numa_map(struct seq_file *m, void *v)
 	if (is_vm_hugetlb_page(vma))
 		seq_puts(m, " huge");
 
-	/* mmap_lock is held by m_start */
-	walk_page_vma(vma, &show_numa_ops, md);
+	/* Skip walking pages if gate VMA */
+	if (vma != get_gate_vma(proc_priv->lock_ctx.mm)) {
+		/* Might sleep. Drop RCU read lock but keep the VMA locked. */
+		drop_rcu(proc_priv);
+		walk_page_vma(vma, get_show_numa_ops(proc_priv), md);
+		reacquire_rcu(proc_priv);
+	}
 
 	if (!md->pages)
 		goto out;
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
deleted file mode 100644
index 4b53dc4a32664..0000000000000
--- a/fs/userfaultfd.c
+++ /dev/null
@@ -1,2231 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  fs/userfaultfd.c
- *
- *  Copyright (C) 2007  Davide Libenzi <davidel@xmailserver.org>
- *  Copyright (C) 2008-2009 Red Hat, Inc.
- *  Copyright (C) 2015  Red Hat, Inc.
- *
- *  Some part derived from fs/eventfd.c (anon inode setup) and
- *  mm/ksm.c (mm hashing).
- */
-
-#include <linux/list.h>
-#include <linux/hashtable.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/mm.h>
-#include <linux/mm.h>
-#include <linux/mm_inline.h>
-#include <linux/mmu_notifier.h>
-#include <linux/poll.h>
-#include <linux/slab.h>
-#include <linux/seq_file.h>
-#include <linux/file.h>
-#include <linux/bug.h>
-#include <linux/anon_inodes.h>
-#include <linux/syscalls.h>
-#include <linux/userfaultfd_k.h>
-#include <linux/mempolicy.h>
-#include <linux/ioctl.h>
-#include <linux/security.h>
-#include <linux/hugetlb.h>
-#include <linux/leafops.h>
-#include <linux/miscdevice.h>
-#include <linux/uio.h>
-
-static int sysctl_unprivileged_userfaultfd __read_mostly;
-
-#ifdef CONFIG_SYSCTL
-static const struct ctl_table vm_userfaultfd_table[] = {
-	{
-		.procname	= "unprivileged_userfaultfd",
-		.data		= &sysctl_unprivileged_userfaultfd,
-		.maxlen		= sizeof(sysctl_unprivileged_userfaultfd),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-};
-#endif
-
-static struct kmem_cache *userfaultfd_ctx_cachep __ro_after_init;
-
-struct userfaultfd_fork_ctx {
-	struct userfaultfd_ctx *orig;
-	struct userfaultfd_ctx *new;
-	struct list_head list;
-};
-
-struct userfaultfd_unmap_ctx {
-	struct userfaultfd_ctx *ctx;
-	unsigned long start;
-	unsigned long end;
-	struct list_head list;
-};
-
-struct userfaultfd_wait_queue {
-	struct uffd_msg msg;
-	wait_queue_entry_t wq;
-	struct userfaultfd_ctx *ctx;
-	bool waken;
-};
-
-struct userfaultfd_wake_range {
-	unsigned long start;
-	unsigned long len;
-};
-
-/* internal indication that UFFD_API ioctl was successfully executed */
-#define UFFD_FEATURE_INITIALIZED		(1u << 31)
-
-static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx)
-{
-	return ctx->features & UFFD_FEATURE_INITIALIZED;
-}
-
-static bool userfaultfd_wp_async_ctx(struct userfaultfd_ctx *ctx)
-{
-	return ctx && (ctx->features & UFFD_FEATURE_WP_ASYNC);
-}
-
-/*
- * Whether WP_UNPOPULATED is enabled on the uffd context.  It is only
- * meaningful when userfaultfd_wp()==true on the vma and when it's
- * anonymous.
- */
-bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma)
-{
-	struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
-
-	if (!ctx)
-		return false;
-
-	return ctx->features & UFFD_FEATURE_WP_UNPOPULATED;
-}
-
-static int userfaultfd_wake_function(wait_queue_entry_t *wq, unsigned mode,
-				     int wake_flags, void *key)
-{
-	struct userfaultfd_wake_range *range = key;
-	int ret;
-	struct userfaultfd_wait_queue *uwq;
-	unsigned long start, len;
-
-	uwq = container_of(wq, struct userfaultfd_wait_queue, wq);
-	ret = 0;
-	/* len == 0 means wake all */
-	start = range->start;
-	len = range->len;
-	if (len && (start > uwq->msg.arg.pagefault.address ||
-		    start + len <= uwq->msg.arg.pagefault.address))
-		goto out;
-	WRITE_ONCE(uwq->waken, true);
-	/*
-	 * The Program-Order guarantees provided by the scheduler
-	 * ensure uwq->waken is visible before the task is woken.
-	 */
-	ret = wake_up_state(wq->private, mode);
-	if (ret) {
-		/*
-		 * Wake only once, autoremove behavior.
-		 *
-		 * After the effect of list_del_init is visible to the other
-		 * CPUs, the waitqueue may disappear from under us, see the
-		 * !list_empty_careful() in handle_userfault().
-		 *
-		 * try_to_wake_up() has an implicit smp_mb(), and the
-		 * wq->private is read before calling the extern function
-		 * "wake_up_state" (which in turns calls try_to_wake_up).
-		 */
-		list_del_init(&wq->entry);
-	}
-out:
-	return ret;
-}
-
-/**
- * userfaultfd_ctx_get - Acquires a reference to the internal userfaultfd
- * context.
- * @ctx: [in] Pointer to the userfaultfd context.
- */
-static void userfaultfd_ctx_get(struct userfaultfd_ctx *ctx)
-{
-	refcount_inc(&ctx->refcount);
-}
-
-/**
- * userfaultfd_ctx_put - Releases a reference to the internal userfaultfd
- * context.
- * @ctx: [in] Pointer to userfaultfd context.
- *
- * The userfaultfd context reference must have been previously acquired either
- * with userfaultfd_ctx_get() or userfaultfd_ctx_fdget().
- */
-static void userfaultfd_ctx_put(struct userfaultfd_ctx *ctx)
-{
-	if (refcount_dec_and_test(&ctx->refcount)) {
-		VM_WARN_ON_ONCE(spin_is_locked(&ctx->fault_pending_wqh.lock));
-		VM_WARN_ON_ONCE(waitqueue_active(&ctx->fault_pending_wqh));
-		VM_WARN_ON_ONCE(spin_is_locked(&ctx->fault_wqh.lock));
-		VM_WARN_ON_ONCE(waitqueue_active(&ctx->fault_wqh));
-		VM_WARN_ON_ONCE(spin_is_locked(&ctx->event_wqh.lock));
-		VM_WARN_ON_ONCE(waitqueue_active(&ctx->event_wqh));
-		VM_WARN_ON_ONCE(spin_is_locked(&ctx->fd_wqh.lock));
-		VM_WARN_ON_ONCE(waitqueue_active(&ctx->fd_wqh));
-		mmdrop(ctx->mm);
-		kmem_cache_free(userfaultfd_ctx_cachep, ctx);
-	}
-}
-
-static inline void msg_init(struct uffd_msg *msg)
-{
-	BUILD_BUG_ON(sizeof(struct uffd_msg) != 32);
-	/*
-	 * Must use memset to zero out the paddings or kernel data is
-	 * leaked to userland.
-	 */
-	memset(msg, 0, sizeof(struct uffd_msg));
-}
-
-static inline struct uffd_msg userfault_msg(unsigned long address,
-					    unsigned long real_address,
-					    unsigned int flags,
-					    unsigned long reason,
-					    unsigned int features)
-{
-	struct uffd_msg msg;
-
-	msg_init(&msg);
-	msg.event = UFFD_EVENT_PAGEFAULT;
-
-	msg.arg.pagefault.address = (features & UFFD_FEATURE_EXACT_ADDRESS) ?
-				    real_address : address;
-
-	/*
-	 * These flags indicate why the userfault occurred:
-	 * - UFFD_PAGEFAULT_FLAG_WP indicates a write protect fault.
-	 * - UFFD_PAGEFAULT_FLAG_MINOR indicates a minor fault.
-	 * - Neither of these flags being set indicates a MISSING fault.
-	 *
-	 * Separately, UFFD_PAGEFAULT_FLAG_WRITE indicates it was a write
-	 * fault. Otherwise, it was a read fault.
-	 */
-	if (flags & FAULT_FLAG_WRITE)
-		msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WRITE;
-	if (reason & VM_UFFD_WP)
-		msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WP;
-	if (reason & VM_UFFD_MINOR)
-		msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_MINOR;
-	if (features & UFFD_FEATURE_THREAD_ID)
-		msg.arg.pagefault.feat.ptid = task_pid_vnr(current);
-	return msg;
-}
-
-#ifdef CONFIG_HUGETLB_PAGE
-/*
- * Same functionality as userfaultfd_must_wait below with modifications for
- * hugepmd ranges.
- */
-static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
-					      struct vm_fault *vmf,
-					      unsigned long reason)
-{
-	struct vm_area_struct *vma = vmf->vma;
-	pte_t *ptep, pte;
-
-	assert_fault_locked(vmf);
-
-	ptep = hugetlb_walk(vma, vmf->address, vma_mmu_pagesize(vma));
-	if (!ptep)
-		return true;
-
-	pte = huge_ptep_get(vma->vm_mm, vmf->address, ptep);
-
-	/*
-	 * Lockless access: we're in a wait_event so it's ok if it
-	 * changes under us.
-	 */
-
-	/* Entry is still missing, wait for userspace to resolve the fault. */
-	if (huge_pte_none(pte))
-		return true;
-	/* UFFD PTE markers require userspace to resolve the fault. */
-	if (pte_is_uffd_marker(pte))
-		return true;
-	/*
-	 * If VMA has UFFD WP faults enabled and WP fault, wait for userspace to
-	 * resolve the fault.
-	 */
-	if (!huge_pte_write(pte) && (reason & VM_UFFD_WP))
-		return true;
-
-	return false;
-}
-#else
-static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
-					      struct vm_fault *vmf,
-					      unsigned long reason)
-{
-	/* Should never get here. */
-	VM_WARN_ON_ONCE(1);
-	return false;
-}
-#endif /* CONFIG_HUGETLB_PAGE */
-
-/*
- * Verify the pagetables are still not ok after having registered into
- * the fault_pending_wqh to avoid userland having to UFFDIO_WAKE any
- * userfault that has already been resolved, if userfaultfd_read_iter and
- * UFFDIO_COPY|ZEROPAGE are being run simultaneously on two different
- * threads.
- */
-static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
-					 struct vm_fault *vmf,
-					 unsigned long reason)
-{
-	struct mm_struct *mm = ctx->mm;
-	unsigned long address = vmf->address;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
-	pmd_t *pmd, _pmd;
-	pte_t *pte;
-	pte_t ptent;
-	bool ret;
-
-	assert_fault_locked(vmf);
-
-	pgd = pgd_offset(mm, address);
-	if (!pgd_present(*pgd))
-		return true;
-	p4d = p4d_offset(pgd, address);
-	if (!p4d_present(*p4d))
-		return true;
-	pud = pud_offset(p4d, address);
-	if (!pud_present(*pud))
-		return true;
-	pmd = pmd_offset(pud, address);
-again:
-	_pmd = pmdp_get_lockless(pmd);
-	if (pmd_none(_pmd))
-		return true;
-
-	/*
-	 * A race could arise which would result in a softleaf entry such as
-	 * migration entry unexpectedly being present in the PMD, so explicitly
-	 * check for this and bail out if so.
-	 */
-	if (!pmd_present(_pmd))
-		return false;
-
-	if (pmd_trans_huge(_pmd))
-		return !pmd_write(_pmd) && (reason & VM_UFFD_WP);
-
-	pte = pte_offset_map(pmd, address);
-	if (!pte)
-		goto again;
-
-	/*
-	 * Lockless access: we're in a wait_event so it's ok if it
-	 * changes under us.
-	 */
-	ptent = ptep_get(pte);
-
-	ret = true;
-	/* Entry is still missing, wait for userspace to resolve the fault. */
-	if (pte_none(ptent))
-		goto out;
-	/* UFFD PTE markers require userspace to resolve the fault. */
-	if (pte_is_uffd_marker(ptent))
-		goto out;
-	/*
-	 * If VMA has UFFD WP faults enabled and WP fault, wait for userspace to
-	 * resolve the fault.
-	 */
-	if (!pte_write(ptent) && (reason & VM_UFFD_WP))
-		goto out;
-
-	ret = false;
-out:
-	pte_unmap(pte);
-	return ret;
-}
-
-static inline unsigned int userfaultfd_get_blocking_state(unsigned int flags)
-{
-	if (flags & FAULT_FLAG_INTERRUPTIBLE)
-		return TASK_INTERRUPTIBLE;
-
-	if (flags & FAULT_FLAG_KILLABLE)
-		return TASK_KILLABLE;
-
-	return TASK_UNINTERRUPTIBLE;
-}
-
-/*
- * The locking rules involved in returning VM_FAULT_RETRY depending on
- * FAULT_FLAG_ALLOW_RETRY, FAULT_FLAG_RETRY_NOWAIT and
- * FAULT_FLAG_KILLABLE are not straightforward. The "Caution"
- * recommendation in __lock_page_or_retry is not an understatement.
- *
- * If FAULT_FLAG_ALLOW_RETRY is set, the mmap_lock must be released
- * before returning VM_FAULT_RETRY only if FAULT_FLAG_RETRY_NOWAIT is
- * not set.
- *
- * If FAULT_FLAG_ALLOW_RETRY is set but FAULT_FLAG_KILLABLE is not
- * set, VM_FAULT_RETRY can still be returned if and only if there are
- * fatal_signal_pending()s, and the mmap_lock must be released before
- * returning it.
- */
-vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
-{
-	struct vm_area_struct *vma = vmf->vma;
-	struct mm_struct *mm = vma->vm_mm;
-	struct userfaultfd_ctx *ctx;
-	struct userfaultfd_wait_queue uwq;
-	vm_fault_t ret = VM_FAULT_SIGBUS;
-	bool must_wait;
-	unsigned int blocking_state;
-
-	/*
-	 * We don't do userfault handling for the final child pid update
-	 * and when coredumping (faults triggered by get_dump_page()).
-	 */
-	if (current->flags & (PF_EXITING|PF_DUMPCORE))
-		goto out;
-
-	assert_fault_locked(vmf);
-
-	ctx = vma->vm_userfaultfd_ctx.ctx;
-	if (!ctx)
-		goto out;
-
-	VM_WARN_ON_ONCE(ctx->mm != mm);
-
-	/* Any unrecognized flag is a bug. */
-	VM_WARN_ON_ONCE(reason & ~__VM_UFFD_FLAGS);
-	/* 0 or > 1 flags set is a bug; we expect exactly 1. */
-	VM_WARN_ON_ONCE(!reason || (reason & (reason - 1)));
-
-	if (ctx->features & UFFD_FEATURE_SIGBUS)
-		goto out;
-	if (!(vmf->flags & FAULT_FLAG_USER) && (ctx->flags & UFFD_USER_MODE_ONLY))
-		goto out;
-
-	/*
-	 * Check that we can return VM_FAULT_RETRY.
-	 *
-	 * NOTE: it should become possible to return VM_FAULT_RETRY
-	 * even if FAULT_FLAG_TRIED is set without leading to gup()
-	 * -EBUSY failures, if the userfaultfd is to be extended for
-	 * VM_UFFD_WP tracking and we intend to arm the userfault
-	 * without first stopping userland access to the memory. For
-	 * VM_UFFD_MISSING userfaults this is enough for now.
-	 */
-	if (unlikely(!(vmf->flags & FAULT_FLAG_ALLOW_RETRY))) {
-		/*
-		 * Validate the invariant that nowait must allow retry
-		 * to be sure not to return SIGBUS erroneously on
-		 * nowait invocations.
-		 */
-		VM_WARN_ON_ONCE(vmf->flags & FAULT_FLAG_RETRY_NOWAIT);
-#ifdef CONFIG_DEBUG_VM
-		if (printk_ratelimit()) {
-			pr_warn("FAULT_FLAG_ALLOW_RETRY missing %x\n",
-				vmf->flags);
-			dump_stack();
-		}
-#endif
-		goto out;
-	}
-
-	/*
-	 * Handle nowait, not much to do other than tell it to retry
-	 * and wait.
-	 */
-	ret = VM_FAULT_RETRY;
-	if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
-		goto out;
-
-	if (unlikely(READ_ONCE(ctx->released))) {
-		/*
-		 * If a concurrent release is detected, do not return
-		 * VM_FAULT_SIGBUS or VM_FAULT_NOPAGE, but instead always
-		 * return VM_FAULT_RETRY with lock released proactively.
-		 *
-		 * If we were to return VM_FAULT_SIGBUS here, the non
-		 * cooperative manager would be instead forced to
-		 * always call UFFDIO_UNREGISTER before it can safely
-		 * close the uffd, to avoid involuntary SIGBUS triggered.
-		 *
-		 * If we were to return VM_FAULT_NOPAGE, it would work for
-		 * the fault path, in which the lock will be released
-		 * later.  However for GUP, faultin_page() does nothing
-		 * special on NOPAGE, so GUP would spin retrying without
-		 * releasing the mmap read lock, causing possible livelock.
-		 *
-		 * Here only VM_FAULT_RETRY would make sure the mmap lock
-		 * be released immediately, so that the thread concurrently
-		 * releasing the userfault would always make progress.
-		 */
-		release_fault_lock(vmf);
-		goto out;
-	}
-
-	/* take the reference before dropping the mmap_lock */
-	userfaultfd_ctx_get(ctx);
-
-	init_waitqueue_func_entry(&uwq.wq, userfaultfd_wake_function);
-	uwq.wq.private = current;
-	uwq.msg = userfault_msg(vmf->address, vmf->real_address, vmf->flags,
-				reason, ctx->features);
-	uwq.ctx = ctx;
-	uwq.waken = false;
-
-	blocking_state = userfaultfd_get_blocking_state(vmf->flags);
-
-        /*
-         * Take the vma lock now, in order to safely call
-         * userfaultfd_huge_must_wait() later. Since acquiring the
-         * (sleepable) vma lock can modify the current task state, that
-         * must be before explicitly calling set_current_state().
-         */
-	if (is_vm_hugetlb_page(vma))
-		hugetlb_vma_lock_read(vma);
-
-	spin_lock_irq(&ctx->fault_pending_wqh.lock);
-	/*
-	 * After the __add_wait_queue the uwq is visible to userland
-	 * through poll/read().
-	 */
-	__add_wait_queue(&ctx->fault_pending_wqh, &uwq.wq);
-	/*
-	 * The smp_mb() after __set_current_state prevents the reads
-	 * following the spin_unlock to happen before the list_add in
-	 * __add_wait_queue.
-	 */
-	set_current_state(blocking_state);
-	spin_unlock_irq(&ctx->fault_pending_wqh.lock);
-
-	if (is_vm_hugetlb_page(vma)) {
-		must_wait = userfaultfd_huge_must_wait(ctx, vmf, reason);
-		hugetlb_vma_unlock_read(vma);
-	} else {
-		must_wait = userfaultfd_must_wait(ctx, vmf, reason);
-	}
-
-	release_fault_lock(vmf);
-
-	if (likely(must_wait && !READ_ONCE(ctx->released))) {
-		wake_up_poll(&ctx->fd_wqh, EPOLLIN);
-		schedule();
-	}
-
-	__set_current_state(TASK_RUNNING);
-
-	/*
-	 * Here we race with the list_del; list_add in
-	 * userfaultfd_ctx_read(), however because we don't ever run
-	 * list_del_init() to refile across the two lists, the prev
-	 * and next pointers will never point to self. list_add also
-	 * would never let any of the two pointers to point to
-	 * self. So list_empty_careful won't risk to see both pointers
-	 * pointing to self at any time during the list refile. The
-	 * only case where list_del_init() is called is the full
-	 * removal in the wake function and there we don't re-list_add
-	 * and it's fine not to block on the spinlock. The uwq on this
-	 * kernel stack can be released after the list_del_init.
-	 */
-	if (!list_empty_careful(&uwq.wq.entry)) {
-		spin_lock_irq(&ctx->fault_pending_wqh.lock);
-		/*
-		 * No need of list_del_init(), the uwq on the stack
-		 * will be freed shortly anyway.
-		 */
-		list_del(&uwq.wq.entry);
-		spin_unlock_irq(&ctx->fault_pending_wqh.lock);
-	}
-
-	/*
-	 * ctx may go away after this if the userfault pseudo fd is
-	 * already released.
-	 */
-	userfaultfd_ctx_put(ctx);
-
-out:
-	return ret;
-}
-
-static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
-					      struct userfaultfd_wait_queue *ewq)
-{
-	struct userfaultfd_ctx *release_new_ctx;
-
-	if (WARN_ON_ONCE(current->flags & PF_EXITING))
-		goto out;
-
-	ewq->ctx = ctx;
-	init_waitqueue_entry(&ewq->wq, current);
-	release_new_ctx = NULL;
-
-	spin_lock_irq(&ctx->event_wqh.lock);
-	/*
-	 * After the __add_wait_queue the uwq is visible to userland
-	 * through poll/read().
-	 */
-	__add_wait_queue(&ctx->event_wqh, &ewq->wq);
-	for (;;) {
-		set_current_state(TASK_KILLABLE);
-		if (ewq->msg.event == 0)
-			break;
-		if (READ_ONCE(ctx->released) ||
-		    fatal_signal_pending(current)) {
-			/*
-			 * &ewq->wq may be queued in fork_event, but
-			 * __remove_wait_queue ignores the head
-			 * parameter. It would be a problem if it
-			 * didn't.
-			 */
-			__remove_wait_queue(&ctx->event_wqh, &ewq->wq);
-			if (ewq->msg.event == UFFD_EVENT_FORK) {
-				struct userfaultfd_ctx *new;
-
-				new = (struct userfaultfd_ctx *)
-					(unsigned long)
-					ewq->msg.arg.reserved.reserved1;
-				release_new_ctx = new;
-			}
-			break;
-		}
-
-		spin_unlock_irq(&ctx->event_wqh.lock);
-
-		wake_up_poll(&ctx->fd_wqh, EPOLLIN);
-		schedule();
-
-		spin_lock_irq(&ctx->event_wqh.lock);
-	}
-	__set_current_state(TASK_RUNNING);
-	spin_unlock_irq(&ctx->event_wqh.lock);
-
-	if (release_new_ctx) {
-		userfaultfd_release_new(release_new_ctx);
-		userfaultfd_ctx_put(release_new_ctx);
-	}
-
-	/*
-	 * ctx may go away after this if the userfault pseudo fd is
-	 * already released.
-	 */
-out:
-	atomic_dec(&ctx->mmap_changing);
-	VM_WARN_ON_ONCE(atomic_read(&ctx->mmap_changing) < 0);
-	userfaultfd_ctx_put(ctx);
-}
-
-static void userfaultfd_event_complete(struct userfaultfd_ctx *ctx,
-				       struct userfaultfd_wait_queue *ewq)
-{
-	ewq->msg.event = 0;
-	wake_up_locked(&ctx->event_wqh);
-	__remove_wait_queue(&ctx->event_wqh, &ewq->wq);
-}
-
-int dup_userfaultfd(struct vm_area_struct *vma, struct list_head *fcs)
-{
-	struct userfaultfd_ctx *ctx = NULL, *octx;
-	struct userfaultfd_fork_ctx *fctx;
-
-	octx = vma->vm_userfaultfd_ctx.ctx;
-	if (!octx)
-		return 0;
-
-	if (!(octx->features & UFFD_FEATURE_EVENT_FORK)) {
-		userfaultfd_reset_ctx(vma);
-		return 0;
-	}
-
-	list_for_each_entry(fctx, fcs, list)
-		if (fctx->orig == octx) {
-			ctx = fctx->new;
-			break;
-		}
-
-	if (!ctx) {
-		fctx = kmalloc_obj(*fctx);
-		if (!fctx)
-			return -ENOMEM;
-
-		ctx = kmem_cache_alloc(userfaultfd_ctx_cachep, GFP_KERNEL);
-		if (!ctx) {
-			kfree(fctx);
-			return -ENOMEM;
-		}
-
-		refcount_set(&ctx->refcount, 1);
-		ctx->flags = octx->flags;
-		ctx->features = octx->features;
-		ctx->released = false;
-		init_rwsem(&ctx->map_changing_lock);
-		atomic_set(&ctx->mmap_changing, 0);
-		ctx->mm = vma->vm_mm;
-		mmgrab(ctx->mm);
-
-		userfaultfd_ctx_get(octx);
-		down_write(&octx->map_changing_lock);
-		atomic_inc(&octx->mmap_changing);
-		up_write(&octx->map_changing_lock);
-		fctx->orig = octx;
-		fctx->new = ctx;
-		list_add_tail(&fctx->list, fcs);
-	}
-
-	vma->vm_userfaultfd_ctx.ctx = ctx;
-	return 0;
-}
-
-static void dup_fctx(struct userfaultfd_fork_ctx *fctx)
-{
-	struct userfaultfd_ctx *ctx = fctx->orig;
-	struct userfaultfd_wait_queue ewq;
-
-	msg_init(&ewq.msg);
-
-	ewq.msg.event = UFFD_EVENT_FORK;
-	ewq.msg.arg.reserved.reserved1 = (unsigned long)fctx->new;
-
-	userfaultfd_event_wait_completion(ctx, &ewq);
-}
-
-void dup_userfaultfd_complete(struct list_head *fcs)
-{
-	struct userfaultfd_fork_ctx *fctx, *n;
-
-	list_for_each_entry_safe(fctx, n, fcs, list) {
-		dup_fctx(fctx);
-		list_del(&fctx->list);
-		kfree(fctx);
-	}
-}
-
-void dup_userfaultfd_fail(struct list_head *fcs)
-{
-	struct userfaultfd_fork_ctx *fctx, *n;
-
-	/*
-	 * An error has occurred on fork, we will tear memory down, but have
-	 * allocated memory for fctx's and raised reference counts for both the
-	 * original and child contexts (and on the mm for each as a result).
-	 *
-	 * These would ordinarily be taken care of by a user handling the event,
-	 * but we are no longer doing so, so manually clean up here.
-	 *
-	 * mm tear down will take care of cleaning up VMA contexts.
-	 */
-	list_for_each_entry_safe(fctx, n, fcs, list) {
-		struct userfaultfd_ctx *octx = fctx->orig;
-		struct userfaultfd_ctx *ctx = fctx->new;
-
-		atomic_dec(&octx->mmap_changing);
-		VM_WARN_ON_ONCE(atomic_read(&octx->mmap_changing) < 0);
-		userfaultfd_ctx_put(octx);
-		userfaultfd_ctx_put(ctx);
-
-		list_del(&fctx->list);
-		kfree(fctx);
-	}
-}
-
-void mremap_userfaultfd_prep(struct vm_area_struct *vma,
-			     struct vm_userfaultfd_ctx *vm_ctx)
-{
-	struct userfaultfd_ctx *ctx;
-
-	ctx = vma->vm_userfaultfd_ctx.ctx;
-
-	if (!ctx)
-		return;
-
-	if (ctx->features & UFFD_FEATURE_EVENT_REMAP) {
-		vm_ctx->ctx = ctx;
-		userfaultfd_ctx_get(ctx);
-		down_write(&ctx->map_changing_lock);
-		atomic_inc(&ctx->mmap_changing);
-		up_write(&ctx->map_changing_lock);
-	} else {
-		/* Drop uffd context if remap feature not enabled */
-		userfaultfd_reset_ctx(vma);
-	}
-}
-
-void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
-				 unsigned long from, unsigned long to,
-				 unsigned long len)
-{
-	struct userfaultfd_ctx *ctx = vm_ctx->ctx;
-	struct userfaultfd_wait_queue ewq;
-
-	if (!ctx)
-		return;
-
-	msg_init(&ewq.msg);
-
-	ewq.msg.event = UFFD_EVENT_REMAP;
-	ewq.msg.arg.remap.from = from;
-	ewq.msg.arg.remap.to = to;
-	ewq.msg.arg.remap.len = len;
-
-	userfaultfd_event_wait_completion(ctx, &ewq);
-}
-
-void mremap_userfaultfd_fail(struct vm_userfaultfd_ctx *vm_ctx)
-{
-	struct userfaultfd_ctx *ctx = vm_ctx->ctx;
-
-	if (!ctx)
-		return;
-
-	userfaultfd_ctx_put(ctx);
-}
-
-bool userfaultfd_remove(struct vm_area_struct *vma,
-			unsigned long start, unsigned long end)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	struct userfaultfd_ctx *ctx;
-	struct userfaultfd_wait_queue ewq;
-
-	ctx = vma->vm_userfaultfd_ctx.ctx;
-	if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_REMOVE))
-		return true;
-
-	userfaultfd_ctx_get(ctx);
-	down_write(&ctx->map_changing_lock);
-	atomic_inc(&ctx->mmap_changing);
-	up_write(&ctx->map_changing_lock);
-	mmap_read_unlock(mm);
-
-	msg_init(&ewq.msg);
-
-	ewq.msg.event = UFFD_EVENT_REMOVE;
-	ewq.msg.arg.remove.start = start;
-	ewq.msg.arg.remove.end = end;
-
-	userfaultfd_event_wait_completion(ctx, &ewq);
-
-	return false;
-}
-
-static bool has_unmap_ctx(struct userfaultfd_ctx *ctx, struct list_head *unmaps,
-			  unsigned long start, unsigned long end)
-{
-	struct userfaultfd_unmap_ctx *unmap_ctx;
-
-	list_for_each_entry(unmap_ctx, unmaps, list)
-		if (unmap_ctx->ctx == ctx && unmap_ctx->start == start &&
-		    unmap_ctx->end == end)
-			return true;
-
-	return false;
-}
-
-int userfaultfd_unmap_prep(struct vm_area_struct *vma, unsigned long start,
-			   unsigned long end, struct list_head *unmaps)
-{
-	struct userfaultfd_unmap_ctx *unmap_ctx;
-	struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
-
-	if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_UNMAP) ||
-	    has_unmap_ctx(ctx, unmaps, start, end))
-		return 0;
-
-	unmap_ctx = kzalloc_obj(*unmap_ctx);
-	if (!unmap_ctx)
-		return -ENOMEM;
-
-	userfaultfd_ctx_get(ctx);
-	down_write(&ctx->map_changing_lock);
-	atomic_inc(&ctx->mmap_changing);
-	up_write(&ctx->map_changing_lock);
-	unmap_ctx->ctx = ctx;
-	unmap_ctx->start = start;
-	unmap_ctx->end = end;
-	list_add_tail(&unmap_ctx->list, unmaps);
-
-	return 0;
-}
-
-void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf)
-{
-	struct userfaultfd_unmap_ctx *ctx, *n;
-	struct userfaultfd_wait_queue ewq;
-
-	list_for_each_entry_safe(ctx, n, uf, list) {
-		msg_init(&ewq.msg);
-
-		ewq.msg.event = UFFD_EVENT_UNMAP;
-		ewq.msg.arg.remove.start = ctx->start;
-		ewq.msg.arg.remove.end = ctx->end;
-
-		userfaultfd_event_wait_completion(ctx->ctx, &ewq);
-
-		list_del(&ctx->list);
-		kfree(ctx);
-	}
-}
-
-static int userfaultfd_release(struct inode *inode, struct file *file)
-{
-	struct userfaultfd_ctx *ctx = file->private_data;
-	struct mm_struct *mm = ctx->mm;
-	/* len == 0 means wake all */
-	struct userfaultfd_wake_range range = { .len = 0, };
-
-	WRITE_ONCE(ctx->released, true);
-
-	userfaultfd_release_all(mm, ctx);
-
-	/*
-	 * After no new page faults can wait on this fault_*wqh, flush
-	 * the last page faults that may have been already waiting on
-	 * the fault_*wqh.
-	 */
-	spin_lock_irq(&ctx->fault_pending_wqh.lock);
-	__wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL, &range);
-	__wake_up(&ctx->fault_wqh, TASK_NORMAL, 1, &range);
-	spin_unlock_irq(&ctx->fault_pending_wqh.lock);
-
-	/* Flush pending events that may still wait on event_wqh */
-	wake_up_all(&ctx->event_wqh);
-
-	wake_up_poll(&ctx->fd_wqh, EPOLLHUP);
-	userfaultfd_ctx_put(ctx);
-	return 0;
-}
-
-/* fault_pending_wqh.lock must be hold by the caller */
-static inline struct userfaultfd_wait_queue *find_userfault_in(
-		wait_queue_head_t *wqh)
-{
-	wait_queue_entry_t *wq;
-	struct userfaultfd_wait_queue *uwq;
-
-	lockdep_assert_held(&wqh->lock);
-
-	uwq = NULL;
-	if (!waitqueue_active(wqh))
-		goto out;
-	/* walk in reverse to provide FIFO behavior to read userfaults */
-	wq = list_last_entry(&wqh->head, typeof(*wq), entry);
-	uwq = container_of(wq, struct userfaultfd_wait_queue, wq);
-out:
-	return uwq;
-}
-
-static inline struct userfaultfd_wait_queue *find_userfault(
-		struct userfaultfd_ctx *ctx)
-{
-	return find_userfault_in(&ctx->fault_pending_wqh);
-}
-
-static inline struct userfaultfd_wait_queue *find_userfault_evt(
-		struct userfaultfd_ctx *ctx)
-{
-	return find_userfault_in(&ctx->event_wqh);
-}
-
-static __poll_t userfaultfd_poll(struct file *file, poll_table *wait)
-{
-	struct userfaultfd_ctx *ctx = file->private_data;
-	__poll_t ret;
-
-	poll_wait(file, &ctx->fd_wqh, wait);
-
-	if (!userfaultfd_is_initialized(ctx))
-		return EPOLLERR;
-
-	/*
-	 * poll() never guarantees that read won't block.
-	 * userfaults can be waken before they're read().
-	 */
-	if (unlikely(!(file->f_flags & O_NONBLOCK)))
-		return EPOLLERR;
-	/*
-	 * lockless access to see if there are pending faults
-	 * __pollwait last action is the add_wait_queue but
-	 * the spin_unlock would allow the waitqueue_active to
-	 * pass above the actual list_add inside
-	 * add_wait_queue critical section. So use a full
-	 * memory barrier to serialize the list_add write of
-	 * add_wait_queue() with the waitqueue_active read
-	 * below.
-	 */
-	ret = 0;
-	smp_mb();
-	if (waitqueue_active(&ctx->fault_pending_wqh))
-		ret = EPOLLIN;
-	else if (waitqueue_active(&ctx->event_wqh))
-		ret = EPOLLIN;
-
-	return ret;
-}
-
-static const struct file_operations userfaultfd_fops;
-
-static int resolve_userfault_fork(struct userfaultfd_ctx *new,
-				  struct inode *inode,
-				  struct uffd_msg *msg)
-{
-	int fd;
-
-	fd = anon_inode_create_getfd("[userfaultfd]", &userfaultfd_fops, new,
-			O_RDONLY | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode);
-	if (fd < 0)
-		return fd;
-
-	msg->arg.reserved.reserved1 = 0;
-	msg->arg.fork.ufd = fd;
-	return 0;
-}
-
-static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait,
-				    struct uffd_msg *msg, struct inode *inode)
-{
-	ssize_t ret;
-	DECLARE_WAITQUEUE(wait, current);
-	struct userfaultfd_wait_queue *uwq;
-	/*
-	 * Handling fork event requires sleeping operations, so
-	 * we drop the event_wqh lock, then do these ops, then
-	 * lock it back and wake up the waiter. While the lock is
-	 * dropped the ewq may go away so we keep track of it
-	 * carefully.
-	 */
-	LIST_HEAD(fork_event);
-	struct userfaultfd_ctx *fork_nctx = NULL;
-
-	/* always take the fd_wqh lock before the fault_pending_wqh lock */
-	spin_lock_irq(&ctx->fd_wqh.lock);
-	__add_wait_queue(&ctx->fd_wqh, &wait);
-	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		spin_lock(&ctx->fault_pending_wqh.lock);
-		uwq = find_userfault(ctx);
-		if (uwq) {
-			/*
-			 * Use a seqcount to repeat the lockless check
-			 * in wake_userfault() to avoid missing
-			 * wakeups because during the refile both
-			 * waitqueue could become empty if this is the
-			 * only userfault.
-			 */
-			write_seqcount_begin(&ctx->refile_seq);
-
-			/*
-			 * The fault_pending_wqh.lock prevents the uwq
-			 * to disappear from under us.
-			 *
-			 * Refile this userfault from
-			 * fault_pending_wqh to fault_wqh, it's not
-			 * pending anymore after we read it.
-			 *
-			 * Use list_del() by hand (as
-			 * userfaultfd_wake_function also uses
-			 * list_del_init() by hand) to be sure nobody
-			 * changes __remove_wait_queue() to use
-			 * list_del_init() in turn breaking the
-			 * !list_empty_careful() check in
-			 * handle_userfault(). The uwq->wq.head list
-			 * must never be empty at any time during the
-			 * refile, or the waitqueue could disappear
-			 * from under us. The "wait_queue_head_t"
-			 * parameter of __remove_wait_queue() is unused
-			 * anyway.
-			 */
-			list_del(&uwq->wq.entry);
-			add_wait_queue(&ctx->fault_wqh, &uwq->wq);
-
-			write_seqcount_end(&ctx->refile_seq);
-
-			/* careful to always initialize msg if ret == 0 */
-			*msg = uwq->msg;
-			spin_unlock(&ctx->fault_pending_wqh.lock);
-			ret = 0;
-			break;
-		}
-		spin_unlock(&ctx->fault_pending_wqh.lock);
-
-		spin_lock(&ctx->event_wqh.lock);
-		uwq = find_userfault_evt(ctx);
-		if (uwq) {
-			*msg = uwq->msg;
-
-			if (uwq->msg.event == UFFD_EVENT_FORK) {
-				fork_nctx = (struct userfaultfd_ctx *)
-					(unsigned long)
-					uwq->msg.arg.reserved.reserved1;
-				list_move(&uwq->wq.entry, &fork_event);
-				/*
-				 * fork_nctx can be freed as soon as
-				 * we drop the lock, unless we take a
-				 * reference on it.
-				 */
-				userfaultfd_ctx_get(fork_nctx);
-				spin_unlock(&ctx->event_wqh.lock);
-				ret = 0;
-				break;
-			}
-
-			userfaultfd_event_complete(ctx, uwq);
-			spin_unlock(&ctx->event_wqh.lock);
-			ret = 0;
-			break;
-		}
-		spin_unlock(&ctx->event_wqh.lock);
-
-		if (signal_pending(current)) {
-			ret = -ERESTARTSYS;
-			break;
-		}
-		if (no_wait) {
-			ret = -EAGAIN;
-			break;
-		}
-		spin_unlock_irq(&ctx->fd_wqh.lock);
-		schedule();
-		spin_lock_irq(&ctx->fd_wqh.lock);
-	}
-	__remove_wait_queue(&ctx->fd_wqh, &wait);
-	__set_current_state(TASK_RUNNING);
-	spin_unlock_irq(&ctx->fd_wqh.lock);
-
-	if (!ret && msg->event == UFFD_EVENT_FORK) {
-		ret = resolve_userfault_fork(fork_nctx, inode, msg);
-		spin_lock_irq(&ctx->event_wqh.lock);
-		if (!list_empty(&fork_event)) {
-			/*
-			 * The fork thread didn't abort, so we can
-			 * drop the temporary refcount.
-			 */
-			userfaultfd_ctx_put(fork_nctx);
-
-			uwq = list_first_entry(&fork_event,
-					       typeof(*uwq),
-					       wq.entry);
-			/*
-			 * If fork_event list wasn't empty and in turn
-			 * the event wasn't already released by fork
-			 * (the event is allocated on fork kernel
-			 * stack), put the event back to its place in
-			 * the event_wq. fork_event head will be freed
-			 * as soon as we return so the event cannot
-			 * stay queued there no matter the current
-			 * "ret" value.
-			 */
-			list_del(&uwq->wq.entry);
-			__add_wait_queue(&ctx->event_wqh, &uwq->wq);
-
-			/*
-			 * Leave the event in the waitqueue and report
-			 * error to userland if we failed to resolve
-			 * the userfault fork.
-			 */
-			if (likely(!ret))
-				userfaultfd_event_complete(ctx, uwq);
-		} else {
-			/*
-			 * Here the fork thread aborted and the
-			 * refcount from the fork thread on fork_nctx
-			 * has already been released. We still hold
-			 * the reference we took before releasing the
-			 * lock above. If resolve_userfault_fork
-			 * failed we've to drop it because the
-			 * fork_nctx has to be freed in such case. If
-			 * it succeeded we'll hold it because the new
-			 * uffd references it.
-			 */
-			if (ret)
-				userfaultfd_ctx_put(fork_nctx);
-		}
-		spin_unlock_irq(&ctx->event_wqh.lock);
-	}
-
-	return ret;
-}
-
-static ssize_t userfaultfd_read_iter(struct kiocb *iocb, struct iov_iter *to)
-{
-	struct file *file = iocb->ki_filp;
-	struct userfaultfd_ctx *ctx = file->private_data;
-	ssize_t _ret, ret = 0;
-	struct uffd_msg msg;
-	struct inode *inode = file_inode(file);
-	bool no_wait;
-
-	if (!userfaultfd_is_initialized(ctx))
-		return -EINVAL;
-
-	no_wait = file->f_flags & O_NONBLOCK || iocb->ki_flags & IOCB_NOWAIT;
-	for (;;) {
-		if (iov_iter_count(to) < sizeof(msg))
-			return ret ? ret : -EINVAL;
-		_ret = userfaultfd_ctx_read(ctx, no_wait, &msg, inode);
-		if (_ret < 0)
-			return ret ? ret : _ret;
-		_ret = !copy_to_iter_full(&msg, sizeof(msg), to);
-		if (_ret)
-			return ret ? ret : -EFAULT;
-		ret += sizeof(msg);
-		/*
-		 * Allow to read more than one fault at time but only
-		 * block if waiting for the very first one.
-		 */
-		no_wait = true;
-	}
-}
-
-static void __wake_userfault(struct userfaultfd_ctx *ctx,
-			     struct userfaultfd_wake_range *range)
-{
-	spin_lock_irq(&ctx->fault_pending_wqh.lock);
-	/* wake all in the range and autoremove */
-	if (waitqueue_active(&ctx->fault_pending_wqh))
-		__wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL,
-				     range);
-	if (waitqueue_active(&ctx->fault_wqh))
-		__wake_up(&ctx->fault_wqh, TASK_NORMAL, 1, range);
-	spin_unlock_irq(&ctx->fault_pending_wqh.lock);
-}
-
-static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
-					   struct userfaultfd_wake_range *range)
-{
-	unsigned seq;
-	bool need_wakeup;
-
-	/*
-	 * To be sure waitqueue_active() is not reordered by the CPU
-	 * before the pagetable update, use an explicit SMP memory
-	 * barrier here. PT lock release or mmap_read_unlock(mm) still
-	 * have release semantics that can allow the
-	 * waitqueue_active() to be reordered before the pte update.
-	 */
-	smp_mb();
-
-	/*
-	 * Use waitqueue_active because it's very frequent to
-	 * change the address space atomically even if there are no
-	 * userfaults yet. So we take the spinlock only when we're
-	 * sure we've userfaults to wake.
-	 */
-	do {
-		seq = read_seqcount_begin(&ctx->refile_seq);
-		need_wakeup = waitqueue_active(&ctx->fault_pending_wqh) ||
-			waitqueue_active(&ctx->fault_wqh);
-		cond_resched();
-	} while (read_seqcount_retry(&ctx->refile_seq, seq));
-	if (need_wakeup)
-		__wake_userfault(ctx, range);
-}
-
-static __always_inline int validate_unaligned_range(
-	struct mm_struct *mm, __u64 start, __u64 len)
-{
-	__u64 task_size = mm->task_size;
-
-	if (len & ~PAGE_MASK)
-		return -EINVAL;
-	if (!len)
-		return -EINVAL;
-	if (start >= task_size)
-		return -EINVAL;
-	if (len > task_size - start)
-		return -EINVAL;
-	if (start + len <= start)
-		return -EINVAL;
-	return 0;
-}
-
-static __always_inline int validate_range(struct mm_struct *mm,
-					  __u64 start, __u64 len)
-{
-	if (start & ~PAGE_MASK)
-		return -EINVAL;
-
-	return validate_unaligned_range(mm, start, len);
-}
-
-static int userfaultfd_register(struct userfaultfd_ctx *ctx,
-				unsigned long arg)
-{
-	struct mm_struct *mm = ctx->mm;
-	struct vm_area_struct *vma, *cur;
-	int ret;
-	struct uffdio_register uffdio_register;
-	struct uffdio_register __user *user_uffdio_register;
-	vm_flags_t vm_flags;
-	bool found;
-	bool basic_ioctls;
-	unsigned long start, end;
-	struct vma_iterator vmi;
-	bool wp_async = userfaultfd_wp_async_ctx(ctx);
-
-	user_uffdio_register = (struct uffdio_register __user *) arg;
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_register, user_uffdio_register,
-			   sizeof(uffdio_register)-sizeof(__u64)))
-		goto out;
-
-	ret = -EINVAL;
-	if (!uffdio_register.mode)
-		goto out;
-	if (uffdio_register.mode & ~UFFD_API_REGISTER_MODES)
-		goto out;
-	vm_flags = 0;
-	if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING)
-		vm_flags |= VM_UFFD_MISSING;
-	if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) {
-		if (!pgtable_supports_uffd_wp())
-			goto out;
-
-		vm_flags |= VM_UFFD_WP;
-	}
-	if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) {
-#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
-		goto out;
-#endif
-		vm_flags |= VM_UFFD_MINOR;
-	}
-
-	ret = validate_range(mm, uffdio_register.range.start,
-			     uffdio_register.range.len);
-	if (ret)
-		goto out;
-
-	start = uffdio_register.range.start;
-	end = start + uffdio_register.range.len;
-
-	ret = -ENOMEM;
-	if (!mmget_not_zero(mm))
-		goto out;
-
-	ret = -EINVAL;
-	mmap_write_lock(mm);
-	vma_iter_init(&vmi, mm, start);
-	vma = vma_find(&vmi, end);
-	if (!vma)
-		goto out_unlock;
-
-	/*
-	 * If the first vma contains huge pages, make sure start address
-	 * is aligned to huge page size.
-	 */
-	if (is_vm_hugetlb_page(vma)) {
-		unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
-
-		if (start & (vma_hpagesize - 1))
-			goto out_unlock;
-	}
-
-	/*
-	 * Search for not compatible vmas.
-	 */
-	found = false;
-	basic_ioctls = false;
-	cur = vma;
-	do {
-		cond_resched();
-
-		VM_WARN_ON_ONCE(!!cur->vm_userfaultfd_ctx.ctx ^
-				!!(cur->vm_flags & __VM_UFFD_FLAGS));
-
-		/* check not compatible vmas */
-		ret = -EINVAL;
-		if (!vma_can_userfault(cur, vm_flags, wp_async))
-			goto out_unlock;
-
-		/*
-		 * UFFDIO_COPY will fill file holes even without
-		 * PROT_WRITE. This check enforces that if this is a
-		 * MAP_SHARED, the process has write permission to the backing
-		 * file. If VM_MAYWRITE is set it also enforces that on a
-		 * MAP_SHARED vma: there is no F_WRITE_SEAL and no further
-		 * F_WRITE_SEAL can be taken until the vma is destroyed.
-		 */
-		ret = -EPERM;
-		if (unlikely(!(cur->vm_flags & VM_MAYWRITE)))
-			goto out_unlock;
-
-		/*
-		 * If this vma contains ending address, and huge pages
-		 * check alignment.
-		 */
-		if (is_vm_hugetlb_page(cur) && end <= cur->vm_end &&
-		    end > cur->vm_start) {
-			unsigned long vma_hpagesize = vma_kernel_pagesize(cur);
-
-			ret = -EINVAL;
-
-			if (end & (vma_hpagesize - 1))
-				goto out_unlock;
-		}
-		if ((vm_flags & VM_UFFD_WP) && !(cur->vm_flags & VM_MAYWRITE))
-			goto out_unlock;
-
-		/*
-		 * Check that this vma isn't already owned by a
-		 * different userfaultfd. We can't allow more than one
-		 * userfaultfd to own a single vma simultaneously or we
-		 * wouldn't know which one to deliver the userfaults to.
-		 */
-		ret = -EBUSY;
-		if (cur->vm_userfaultfd_ctx.ctx &&
-		    cur->vm_userfaultfd_ctx.ctx != ctx)
-			goto out_unlock;
-
-		/*
-		 * Note vmas containing huge pages
-		 */
-		if (is_vm_hugetlb_page(cur))
-			basic_ioctls = true;
-
-		found = true;
-	} for_each_vma_range(vmi, cur, end);
-	VM_WARN_ON_ONCE(!found);
-
-	ret = userfaultfd_register_range(ctx, vma, vm_flags, start, end,
-					 wp_async);
-
-out_unlock:
-	mmap_write_unlock(mm);
-	mmput(mm);
-	if (!ret) {
-		__u64 ioctls_out;
-
-		ioctls_out = basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
-		    UFFD_API_RANGE_IOCTLS;
-
-		/*
-		 * Declare the WP ioctl only if the WP mode is
-		 * specified and all checks passed with the range
-		 */
-		if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_WP))
-			ioctls_out &= ~((__u64)1 << _UFFDIO_WRITEPROTECT);
-
-		/* CONTINUE ioctl is only supported for MINOR ranges. */
-		if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR))
-			ioctls_out &= ~((__u64)1 << _UFFDIO_CONTINUE);
-
-		/*
-		 * Now that we scanned all vmas we can already tell
-		 * userland which ioctls methods are guaranteed to
-		 * succeed on this range.
-		 */
-		if (put_user(ioctls_out, &user_uffdio_register->ioctls))
-			ret = -EFAULT;
-	}
-out:
-	return ret;
-}
-
-static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
-				  unsigned long arg)
-{
-	struct mm_struct *mm = ctx->mm;
-	struct vm_area_struct *vma, *prev, *cur;
-	int ret;
-	struct uffdio_range uffdio_unregister;
-	bool found;
-	unsigned long start, end, vma_end;
-	const void __user *buf = (void __user *)arg;
-	struct vma_iterator vmi;
-	bool wp_async = userfaultfd_wp_async_ctx(ctx);
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
-		goto out;
-
-	ret = validate_range(mm, uffdio_unregister.start,
-			     uffdio_unregister.len);
-	if (ret)
-		goto out;
-
-	start = uffdio_unregister.start;
-	end = start + uffdio_unregister.len;
-
-	ret = -ENOMEM;
-	if (!mmget_not_zero(mm))
-		goto out;
-
-	mmap_write_lock(mm);
-	ret = -EINVAL;
-	vma_iter_init(&vmi, mm, start);
-	vma = vma_find(&vmi, end);
-	if (!vma)
-		goto out_unlock;
-
-	/*
-	 * If the first vma contains huge pages, make sure start address
-	 * is aligned to huge page size.
-	 */
-	if (is_vm_hugetlb_page(vma)) {
-		unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
-
-		if (start & (vma_hpagesize - 1))
-			goto out_unlock;
-	}
-
-	/*
-	 * Search for not compatible vmas.
-	 */
-	found = false;
-	cur = vma;
-	do {
-		cond_resched();
-
-		VM_WARN_ON_ONCE(!!cur->vm_userfaultfd_ctx.ctx ^
-				!!(cur->vm_flags & __VM_UFFD_FLAGS));
-
-		/*
-		 * Prevent unregistering through a different userfaultfd than
-		 * the one used for registration.
-		 */
-		if (cur->vm_userfaultfd_ctx.ctx &&
-		    cur->vm_userfaultfd_ctx.ctx != ctx)
-			goto out_unlock;
-
-		/*
-		 * Check not compatible vmas, not strictly required
-		 * here as not compatible vmas cannot have an
-		 * userfaultfd_ctx registered on them, but this
-		 * provides for more strict behavior to notice
-		 * unregistration errors.
-		 */
-		if (!vma_can_userfault(cur, cur->vm_flags, wp_async))
-			goto out_unlock;
-
-		found = true;
-	} for_each_vma_range(vmi, cur, end);
-	VM_WARN_ON_ONCE(!found);
-
-	vma_iter_set(&vmi, start);
-	prev = vma_prev(&vmi);
-	if (vma->vm_start < start)
-		prev = vma;
-
-	ret = 0;
-	for_each_vma_range(vmi, vma, end) {
-		cond_resched();
-
-		/* VMA not registered with userfaultfd. */
-		if (!vma->vm_userfaultfd_ctx.ctx)
-			goto skip;
-
-		VM_WARN_ON_ONCE(vma->vm_userfaultfd_ctx.ctx != ctx);
-		VM_WARN_ON_ONCE(!vma_can_userfault(vma, vma->vm_flags, wp_async));
-		VM_WARN_ON_ONCE(!(vma->vm_flags & VM_MAYWRITE));
-
-		if (vma->vm_start > start)
-			start = vma->vm_start;
-		vma_end = min(end, vma->vm_end);
-
-		if (userfaultfd_missing(vma)) {
-			/*
-			 * Wake any concurrent pending userfault while
-			 * we unregister, so they will not hang
-			 * permanently and it avoids userland to call
-			 * UFFDIO_WAKE explicitly.
-			 */
-			struct userfaultfd_wake_range range;
-			range.start = start;
-			range.len = vma_end - start;
-			wake_userfault(vma->vm_userfaultfd_ctx.ctx, &range);
-		}
-
-		vma = userfaultfd_clear_vma(&vmi, prev, vma,
-					    start, vma_end);
-		if (IS_ERR(vma)) {
-			ret = PTR_ERR(vma);
-			break;
-		}
-
-	skip:
-		prev = vma;
-		start = vma->vm_end;
-	}
-
-out_unlock:
-	mmap_write_unlock(mm);
-	mmput(mm);
-out:
-	return ret;
-}
-
-/*
- * userfaultfd_wake may be used in combination with the
- * UFFDIO_*_MODE_DONTWAKE to wakeup userfaults in batches.
- */
-static int userfaultfd_wake(struct userfaultfd_ctx *ctx,
-			    unsigned long arg)
-{
-	int ret;
-	struct uffdio_range uffdio_wake;
-	struct userfaultfd_wake_range range;
-	const void __user *buf = (void __user *)arg;
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake)))
-		goto out;
-
-	ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len);
-	if (ret)
-		goto out;
-
-	range.start = uffdio_wake.start;
-	range.len = uffdio_wake.len;
-
-	/*
-	 * len == 0 means wake all and we don't want to wake all here,
-	 * so check it again to be sure.
-	 */
-	VM_WARN_ON_ONCE(!range.len);
-
-	wake_userfault(ctx, &range);
-	ret = 0;
-
-out:
-	return ret;
-}
-
-static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
-			    unsigned long arg)
-{
-	__s64 ret;
-	struct uffdio_copy uffdio_copy;
-	struct uffdio_copy __user *user_uffdio_copy;
-	struct userfaultfd_wake_range range;
-	uffd_flags_t flags = 0;
-
-	user_uffdio_copy = (struct uffdio_copy __user *) arg;
-
-	ret = -EAGAIN;
-	if (unlikely(atomic_read(&ctx->mmap_changing))) {
-		if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
-			return -EFAULT;
-		goto out;
-	}
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_copy, user_uffdio_copy,
-			   /* don't copy "copy" last field */
-			   sizeof(uffdio_copy)-sizeof(__s64)))
-		goto out;
-
-	ret = validate_unaligned_range(ctx->mm, uffdio_copy.src,
-				       uffdio_copy.len);
-	if (ret)
-		goto out;
-	ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len);
-	if (ret)
-		goto out;
-
-	ret = -EINVAL;
-	if (uffdio_copy.mode & ~(UFFDIO_COPY_MODE_DONTWAKE|UFFDIO_COPY_MODE_WP))
-		goto out;
-	if (uffdio_copy.mode & UFFDIO_COPY_MODE_WP)
-		flags |= MFILL_ATOMIC_WP;
-	if (mmget_not_zero(ctx->mm)) {
-		ret = mfill_atomic_copy(ctx, uffdio_copy.dst, uffdio_copy.src,
-					uffdio_copy.len, flags);
-		mmput(ctx->mm);
-	} else {
-		return -ESRCH;
-	}
-	if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
-		return -EFAULT;
-	if (ret < 0)
-		goto out;
-	VM_WARN_ON_ONCE(!ret);
-	/* len == 0 would wake all */
-	range.len = ret;
-	if (!(uffdio_copy.mode & UFFDIO_COPY_MODE_DONTWAKE)) {
-		range.start = uffdio_copy.dst;
-		wake_userfault(ctx, &range);
-	}
-	ret = range.len == uffdio_copy.len ? 0 : -EAGAIN;
-out:
-	return ret;
-}
-
-static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
-				unsigned long arg)
-{
-	__s64 ret;
-	struct uffdio_zeropage uffdio_zeropage;
-	struct uffdio_zeropage __user *user_uffdio_zeropage;
-	struct userfaultfd_wake_range range;
-
-	user_uffdio_zeropage = (struct uffdio_zeropage __user *) arg;
-
-	ret = -EAGAIN;
-	if (unlikely(atomic_read(&ctx->mmap_changing))) {
-		if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage)))
-			return -EFAULT;
-		goto out;
-	}
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_zeropage, user_uffdio_zeropage,
-			   /* don't copy "zeropage" last field */
-			   sizeof(uffdio_zeropage)-sizeof(__s64)))
-		goto out;
-
-	ret = validate_range(ctx->mm, uffdio_zeropage.range.start,
-			     uffdio_zeropage.range.len);
-	if (ret)
-		goto out;
-	ret = -EINVAL;
-	if (uffdio_zeropage.mode & ~UFFDIO_ZEROPAGE_MODE_DONTWAKE)
-		goto out;
-
-	if (mmget_not_zero(ctx->mm)) {
-		ret = mfill_atomic_zeropage(ctx, uffdio_zeropage.range.start,
-					   uffdio_zeropage.range.len);
-		mmput(ctx->mm);
-	} else {
-		return -ESRCH;
-	}
-	if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage)))
-		return -EFAULT;
-	if (ret < 0)
-		goto out;
-	/* len == 0 would wake all */
-	VM_WARN_ON_ONCE(!ret);
-	range.len = ret;
-	if (!(uffdio_zeropage.mode & UFFDIO_ZEROPAGE_MODE_DONTWAKE)) {
-		range.start = uffdio_zeropage.range.start;
-		wake_userfault(ctx, &range);
-	}
-	ret = range.len == uffdio_zeropage.range.len ? 0 : -EAGAIN;
-out:
-	return ret;
-}
-
-static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx,
-				    unsigned long arg)
-{
-	int ret;
-	struct uffdio_writeprotect uffdio_wp;
-	struct uffdio_writeprotect __user *user_uffdio_wp;
-	struct userfaultfd_wake_range range;
-	bool mode_wp, mode_dontwake;
-
-	if (atomic_read(&ctx->mmap_changing))
-		return -EAGAIN;
-
-	user_uffdio_wp = (struct uffdio_writeprotect __user *) arg;
-
-	if (copy_from_user(&uffdio_wp, user_uffdio_wp,
-			   sizeof(struct uffdio_writeprotect)))
-		return -EFAULT;
-
-	ret = validate_range(ctx->mm, uffdio_wp.range.start,
-			     uffdio_wp.range.len);
-	if (ret)
-		return ret;
-
-	if (uffdio_wp.mode & ~(UFFDIO_WRITEPROTECT_MODE_DONTWAKE |
-			       UFFDIO_WRITEPROTECT_MODE_WP))
-		return -EINVAL;
-
-	mode_wp = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP;
-	mode_dontwake = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE;
-
-	if (mode_wp && mode_dontwake)
-		return -EINVAL;
-
-	if (mmget_not_zero(ctx->mm)) {
-		ret = mwriteprotect_range(ctx, uffdio_wp.range.start,
-					  uffdio_wp.range.len, mode_wp);
-		mmput(ctx->mm);
-	} else {
-		return -ESRCH;
-	}
-
-	if (ret)
-		return ret;
-
-	if (!mode_wp && !mode_dontwake) {
-		range.start = uffdio_wp.range.start;
-		range.len = uffdio_wp.range.len;
-		wake_userfault(ctx, &range);
-	}
-	return ret;
-}
-
-static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg)
-{
-	__s64 ret;
-	struct uffdio_continue uffdio_continue;
-	struct uffdio_continue __user *user_uffdio_continue;
-	struct userfaultfd_wake_range range;
-	uffd_flags_t flags = 0;
-
-	user_uffdio_continue = (struct uffdio_continue __user *)arg;
-
-	ret = -EAGAIN;
-	if (unlikely(atomic_read(&ctx->mmap_changing))) {
-		if (unlikely(put_user(ret, &user_uffdio_continue->mapped)))
-			return -EFAULT;
-		goto out;
-	}
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_continue, user_uffdio_continue,
-			   /* don't copy the output fields */
-			   sizeof(uffdio_continue) - (sizeof(__s64))))
-		goto out;
-
-	ret = validate_range(ctx->mm, uffdio_continue.range.start,
-			     uffdio_continue.range.len);
-	if (ret)
-		goto out;
-
-	ret = -EINVAL;
-	if (uffdio_continue.mode & ~(UFFDIO_CONTINUE_MODE_DONTWAKE |
-				     UFFDIO_CONTINUE_MODE_WP))
-		goto out;
-	if (uffdio_continue.mode & UFFDIO_CONTINUE_MODE_WP)
-		flags |= MFILL_ATOMIC_WP;
-
-	if (mmget_not_zero(ctx->mm)) {
-		ret = mfill_atomic_continue(ctx, uffdio_continue.range.start,
-					    uffdio_continue.range.len, flags);
-		mmput(ctx->mm);
-	} else {
-		return -ESRCH;
-	}
-
-	if (unlikely(put_user(ret, &user_uffdio_continue->mapped)))
-		return -EFAULT;
-	if (ret < 0)
-		goto out;
-
-	/* len == 0 would wake all */
-	VM_WARN_ON_ONCE(!ret);
-	range.len = ret;
-	if (!(uffdio_continue.mode & UFFDIO_CONTINUE_MODE_DONTWAKE)) {
-		range.start = uffdio_continue.range.start;
-		wake_userfault(ctx, &range);
-	}
-	ret = range.len == uffdio_continue.range.len ? 0 : -EAGAIN;
-
-out:
-	return ret;
-}
-
-static inline int userfaultfd_poison(struct userfaultfd_ctx *ctx, unsigned long arg)
-{
-	__s64 ret;
-	struct uffdio_poison uffdio_poison;
-	struct uffdio_poison __user *user_uffdio_poison;
-	struct userfaultfd_wake_range range;
-
-	user_uffdio_poison = (struct uffdio_poison __user *)arg;
-
-	ret = -EAGAIN;
-	if (unlikely(atomic_read(&ctx->mmap_changing))) {
-		if (unlikely(put_user(ret, &user_uffdio_poison->updated)))
-			return -EFAULT;
-		goto out;
-	}
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_poison, user_uffdio_poison,
-			   /* don't copy the output fields */
-			   sizeof(uffdio_poison) - (sizeof(__s64))))
-		goto out;
-
-	ret = validate_range(ctx->mm, uffdio_poison.range.start,
-			     uffdio_poison.range.len);
-	if (ret)
-		goto out;
-
-	ret = -EINVAL;
-	if (uffdio_poison.mode & ~UFFDIO_POISON_MODE_DONTWAKE)
-		goto out;
-
-	if (mmget_not_zero(ctx->mm)) {
-		ret = mfill_atomic_poison(ctx, uffdio_poison.range.start,
-					  uffdio_poison.range.len, 0);
-		mmput(ctx->mm);
-	} else {
-		return -ESRCH;
-	}
-
-	if (unlikely(put_user(ret, &user_uffdio_poison->updated)))
-		return -EFAULT;
-	if (ret < 0)
-		goto out;
-
-	/* len == 0 would wake all */
-	VM_WARN_ON_ONCE(!ret);
-	range.len = ret;
-	if (!(uffdio_poison.mode & UFFDIO_POISON_MODE_DONTWAKE)) {
-		range.start = uffdio_poison.range.start;
-		wake_userfault(ctx, &range);
-	}
-	ret = range.len == uffdio_poison.range.len ? 0 : -EAGAIN;
-
-out:
-	return ret;
-}
-
-bool userfaultfd_wp_async(struct vm_area_struct *vma)
-{
-	return userfaultfd_wp_async_ctx(vma->vm_userfaultfd_ctx.ctx);
-}
-
-static inline unsigned int uffd_ctx_features(__u64 user_features)
-{
-	/*
-	 * For the current set of features the bits just coincide. Set
-	 * UFFD_FEATURE_INITIALIZED to mark the features as enabled.
-	 */
-	return (unsigned int)user_features | UFFD_FEATURE_INITIALIZED;
-}
-
-static int userfaultfd_move(struct userfaultfd_ctx *ctx,
-			    unsigned long arg)
-{
-	__s64 ret;
-	struct uffdio_move uffdio_move;
-	struct uffdio_move __user *user_uffdio_move;
-	struct userfaultfd_wake_range range;
-	struct mm_struct *mm = ctx->mm;
-
-	user_uffdio_move = (struct uffdio_move __user *) arg;
-
-	ret = -EAGAIN;
-	if (unlikely(atomic_read(&ctx->mmap_changing))) {
-		if (unlikely(put_user(ret, &user_uffdio_move->move)))
-			return -EFAULT;
-		goto out;
-	}
-
-	if (copy_from_user(&uffdio_move, user_uffdio_move,
-			   /* don't copy "move" last field */
-			   sizeof(uffdio_move)-sizeof(__s64)))
-		return -EFAULT;
-
-	/* Do not allow cross-mm moves. */
-	if (mm != current->mm)
-		return -EINVAL;
-
-	ret = validate_range(mm, uffdio_move.dst, uffdio_move.len);
-	if (ret)
-		return ret;
-
-	ret = validate_range(mm, uffdio_move.src, uffdio_move.len);
-	if (ret)
-		return ret;
-
-	if (uffdio_move.mode & ~(UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES|
-				  UFFDIO_MOVE_MODE_DONTWAKE))
-		return -EINVAL;
-
-	if (mmget_not_zero(mm)) {
-		ret = move_pages(ctx, uffdio_move.dst, uffdio_move.src,
-				 uffdio_move.len, uffdio_move.mode);
-		mmput(mm);
-	} else {
-		return -ESRCH;
-	}
-
-	if (unlikely(put_user(ret, &user_uffdio_move->move)))
-		return -EFAULT;
-	if (ret < 0)
-		goto out;
-
-	/* len == 0 would wake all */
-	VM_WARN_ON(!ret);
-	range.len = ret;
-	if (!(uffdio_move.mode & UFFDIO_MOVE_MODE_DONTWAKE)) {
-		range.start = uffdio_move.dst;
-		wake_userfault(ctx, &range);
-	}
-	ret = range.len == uffdio_move.len ? 0 : -EAGAIN;
-
-out:
-	return ret;
-}
-
-/*
- * userland asks for a certain API version and we return which bits
- * and ioctl commands are implemented in this kernel for such API
- * version or -EINVAL if unknown.
- */
-static int userfaultfd_api(struct userfaultfd_ctx *ctx,
-			   unsigned long arg)
-{
-	struct uffdio_api uffdio_api;
-	void __user *buf = (void __user *)arg;
-	unsigned int ctx_features;
-	int ret;
-	__u64 features;
-
-	ret = -EFAULT;
-	if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api)))
-		goto out;
-	features = uffdio_api.features;
-	ret = -EINVAL;
-	if (uffdio_api.api != UFFD_API)
-		goto err_out;
-	ret = -EPERM;
-	if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE))
-		goto err_out;
-
-	/* WP_ASYNC relies on WP_UNPOPULATED, choose it unconditionally */
-	if (features & UFFD_FEATURE_WP_ASYNC)
-		features |= UFFD_FEATURE_WP_UNPOPULATED;
-
-	/* report all available features and ioctls to userland */
-	uffdio_api.features = UFFD_API_FEATURES;
-#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
-	uffdio_api.features &=
-		~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM);
-#endif
-	if (!pgtable_supports_uffd_wp())
-		uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
-
-	if (!uffd_supports_wp_marker()) {
-		uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM;
-		uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED;
-		uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC;
-	}
-
-	ret = -EINVAL;
-	if (features & ~uffdio_api.features)
-		goto err_out;
-
-	uffdio_api.ioctls = UFFD_API_IOCTLS;
-	ret = -EFAULT;
-	if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
-		goto out;
-
-	/* only enable the requested features for this uffd context */
-	ctx_features = uffd_ctx_features(features);
-	ret = -EINVAL;
-	if (cmpxchg(&ctx->features, 0, ctx_features) != 0)
-		goto err_out;
-
-	ret = 0;
-out:
-	return ret;
-err_out:
-	memset(&uffdio_api, 0, sizeof(uffdio_api));
-	if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
-		ret = -EFAULT;
-	goto out;
-}
-
-static long userfaultfd_ioctl(struct file *file, unsigned cmd,
-			      unsigned long arg)
-{
-	int ret = -EINVAL;
-	struct userfaultfd_ctx *ctx = file->private_data;
-
-	if (cmd != UFFDIO_API && !userfaultfd_is_initialized(ctx))
-		return -EINVAL;
-
-	switch(cmd) {
-	case UFFDIO_API:
-		ret = userfaultfd_api(ctx, arg);
-		break;
-	case UFFDIO_REGISTER:
-		ret = userfaultfd_register(ctx, arg);
-		break;
-	case UFFDIO_UNREGISTER:
-		ret = userfaultfd_unregister(ctx, arg);
-		break;
-	case UFFDIO_WAKE:
-		ret = userfaultfd_wake(ctx, arg);
-		break;
-	case UFFDIO_COPY:
-		ret = userfaultfd_copy(ctx, arg);
-		break;
-	case UFFDIO_ZEROPAGE:
-		ret = userfaultfd_zeropage(ctx, arg);
-		break;
-	case UFFDIO_MOVE:
-		ret = userfaultfd_move(ctx, arg);
-		break;
-	case UFFDIO_WRITEPROTECT:
-		ret = userfaultfd_writeprotect(ctx, arg);
-		break;
-	case UFFDIO_CONTINUE:
-		ret = userfaultfd_continue(ctx, arg);
-		break;
-	case UFFDIO_POISON:
-		ret = userfaultfd_poison(ctx, arg);
-		break;
-	}
-	return ret;
-}
-
-#ifdef CONFIG_PROC_FS
-static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f)
-{
-	struct userfaultfd_ctx *ctx = f->private_data;
-	wait_queue_entry_t *wq;
-	unsigned long pending = 0, total = 0;
-
-	spin_lock_irq(&ctx->fault_pending_wqh.lock);
-	list_for_each_entry(wq, &ctx->fault_pending_wqh.head, entry) {
-		pending++;
-		total++;
-	}
-	list_for_each_entry(wq, &ctx->fault_wqh.head, entry) {
-		total++;
-	}
-	spin_unlock_irq(&ctx->fault_pending_wqh.lock);
-
-	/*
-	 * If more protocols will be added, there will be all shown
-	 * separated by a space. Like this:
-	 *	protocols: aa:... bb:...
-	 */
-	seq_printf(m, "pending:\t%lu\ntotal:\t%lu\nAPI:\t%Lx:%x:%Lx\n",
-		   pending, total, UFFD_API, ctx->features,
-		   UFFD_API_IOCTLS|UFFD_API_RANGE_IOCTLS);
-}
-#endif
-
-static const struct file_operations userfaultfd_fops = {
-#ifdef CONFIG_PROC_FS
-	.show_fdinfo	= userfaultfd_show_fdinfo,
-#endif
-	.release	= userfaultfd_release,
-	.poll		= userfaultfd_poll,
-	.read_iter	= userfaultfd_read_iter,
-	.unlocked_ioctl = userfaultfd_ioctl,
-	.compat_ioctl	= compat_ptr_ioctl,
-	.llseek		= noop_llseek,
-};
-
-static void init_once_userfaultfd_ctx(void *mem)
-{
-	struct userfaultfd_ctx *ctx = (struct userfaultfd_ctx *) mem;
-
-	init_waitqueue_head(&ctx->fault_pending_wqh);
-	init_waitqueue_head(&ctx->fault_wqh);
-	init_waitqueue_head(&ctx->event_wqh);
-	init_waitqueue_head(&ctx->fd_wqh);
-	seqcount_spinlock_init(&ctx->refile_seq, &ctx->fault_pending_wqh.lock);
-}
-
-static int new_userfaultfd(int flags)
-{
-	struct userfaultfd_ctx *ctx __free(kfree) = NULL;
-
-	VM_WARN_ON_ONCE(!current->mm);
-
-	/* Check the UFFD_* constants for consistency.  */
-	BUILD_BUG_ON(UFFD_USER_MODE_ONLY & UFFD_SHARED_FCNTL_FLAGS);
-
-	if (flags & ~(UFFD_SHARED_FCNTL_FLAGS | UFFD_USER_MODE_ONLY))
-		return -EINVAL;
-
-	ctx = kmem_cache_alloc(userfaultfd_ctx_cachep, GFP_KERNEL);
-	if (!ctx)
-		return -ENOMEM;
-
-	refcount_set(&ctx->refcount, 1);
-	ctx->flags = flags;
-	ctx->features = 0;
-	ctx->released = false;
-	init_rwsem(&ctx->map_changing_lock);
-	atomic_set(&ctx->mmap_changing, 0);
-	ctx->mm = current->mm;
-
-	FD_PREPARE(fdf, flags & UFFD_SHARED_FCNTL_FLAGS,
-		   anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
-					     O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS),
-					     NULL));
-	if (fdf.err)
-		return fdf.err;
-
-	/* prevent the mm struct to be freed */
-	mmgrab(ctx->mm);
-	fd_prepare_file(fdf)->f_mode |= FMODE_NOWAIT;
-	retain_and_null_ptr(ctx);
-	return fd_publish(fdf);
-}
-
-static inline bool userfaultfd_syscall_allowed(int flags)
-{
-	/* Userspace-only page faults are always allowed */
-	if (flags & UFFD_USER_MODE_ONLY)
-		return true;
-
-	/*
-	 * The user is requesting a userfaultfd which can handle kernel faults.
-	 * Privileged users are always allowed to do this.
-	 */
-	if (capable(CAP_SYS_PTRACE))
-		return true;
-
-	/* Otherwise, access to kernel fault handling is sysctl controlled. */
-	return sysctl_unprivileged_userfaultfd;
-}
-
-SYSCALL_DEFINE1(userfaultfd, int, flags)
-{
-	if (!userfaultfd_syscall_allowed(flags))
-		return -EPERM;
-
-	return new_userfaultfd(flags);
-}
-
-static long userfaultfd_dev_ioctl(struct file *file, unsigned int cmd, unsigned long flags)
-{
-	if (cmd != USERFAULTFD_IOC_NEW)
-		return -EINVAL;
-
-	return new_userfaultfd(flags);
-}
-
-static const struct file_operations userfaultfd_dev_fops = {
-	.unlocked_ioctl = userfaultfd_dev_ioctl,
-	.compat_ioctl = userfaultfd_dev_ioctl,
-	.owner = THIS_MODULE,
-	.llseek = noop_llseek,
-};
-
-static struct miscdevice userfaultfd_misc = {
-	.minor = MISC_DYNAMIC_MINOR,
-	.name = "userfaultfd",
-	.fops = &userfaultfd_dev_fops
-};
-
-static int __init userfaultfd_init(void)
-{
-	int ret;
-
-	ret = misc_register(&userfaultfd_misc);
-	if (ret)
-		return ret;
-
-	userfaultfd_ctx_cachep = kmem_cache_create("userfaultfd_ctx_cache",
-						sizeof(struct userfaultfd_ctx),
-						0,
-						SLAB_HWCACHE_ALIGN|SLAB_PANIC,
-						init_once_userfaultfd_ctx);
-#ifdef CONFIG_SYSCTL
-	register_sysctl_init("vm", vm_userfaultfd_table);
-#endif
-	return 0;
-}
-__initcall(userfaultfd_init);
author	Mark Brown <broonie@kernel.org>	2026-05-29 17:54:35 +0100
committer	Mark Brown <broonie@kernel.org>	2026-05-29 17:54:35 +0100
commit	76dc299c2ef007e68114b956abec0bc21777b2d9 (patch)
tree	bdb5e5d56848cfefd24dceeab438743c0804b8e9 /fs
parent	686a7ac3f6b13a5800282ddd81d80d71f29f75d6 (diff)
parent	404fb4f38e8f38469dfff4df0205c9d18eeb1f57 (diff)
download	linux-next-history-76dc299c2ef007e68114b956abec0bc21777b2d9.tar.gz