[PATCH 26/64] fs: use mm locking wrappers
From: Davidlohr Bueso
Date: Sun Feb 04 2018 - 20:41:39 EST
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Also fixup some previous userfaultfd changes.
No change in semantics.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
fs/aio.c | 4 ++--
fs/userfaultfd.c | 26 ++++++++++++++------------
include/linux/userfaultfd_k.h | 5 +++--
mm/madvise.c | 4 ++--
4 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 31774b75c372..98affcf36b97 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -512,7 +512,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ctx->mmap_size = nr_pages * PAGE_SIZE;
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
- if (down_write_killable(&mm->mmap_sem)) {
+ if (mm_write_lock_killable(mm, &mmrange)) {
ctx->mmap_size = 0;
aio_free_ring(ctx);
return -EINTR;
@@ -521,7 +521,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
PROT_READ | PROT_WRITE,
MAP_SHARED, 0, &unused, NULL, &mmrange);
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
if (IS_ERR((void *)ctx->mmap_base)) {
ctx->mmap_size = 0;
aio_free_ring(ctx);
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 883fbffb284e..805bdc7ecf2d 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -482,7 +482,7 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason)
vmf->address,
vmf->flags, reason,
vmf->lockrange);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, vmf->lockrange);
if (likely(must_wait && !READ_ONCE(ctx->released) &&
(return_to_userland ? !signal_pending(current) :
@@ -536,7 +536,7 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason)
* and there's no need to retake the mmap_sem
* in such case.
*/
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, vmf->lockrange);
ret = VM_FAULT_NOPAGE;
}
}
@@ -629,13 +629,14 @@ static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
if (release_new_ctx) {
struct vm_area_struct *vma;
struct mm_struct *mm = release_new_ctx->mm;
+ DEFINE_RANGE_LOCK_FULL(mmrange);
/* the various vma->vm_userfaultfd_ctx still points to it */
- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
for (vma = mm->mmap; vma; vma = vma->vm_next)
if (vma->vm_userfaultfd_ctx.ctx == release_new_ctx)
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
userfaultfd_ctx_put(release_new_ctx);
}
@@ -765,7 +766,8 @@ void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
}
bool userfaultfd_remove(struct vm_area_struct *vma,
- unsigned long start, unsigned long end)
+ unsigned long start, unsigned long end,
+ struct range_lock *mmrange)
{
struct mm_struct *mm = vma->vm_mm;
struct userfaultfd_ctx *ctx;
@@ -776,7 +778,7 @@ bool userfaultfd_remove(struct vm_area_struct *vma,
return true;
userfaultfd_ctx_get(ctx);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, mmrange);
msg_init(&ewq.msg);
@@ -870,7 +872,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
* it's critical that released is set to true (above), before
* taking the mmap_sem for writing.
*/
- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
prev = NULL;
for (vma = mm->mmap; vma; vma = vma->vm_next) {
cond_resched();
@@ -893,7 +895,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
vma->vm_flags = new_flags;
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
}
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
mmput(mm);
wakeup:
/*
@@ -1321,7 +1323,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
if (!mmget_not_zero(mm))
goto out;
- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
vma = find_vma_prev(mm, start, &prev);
if (!vma)
goto out_unlock;
@@ -1450,7 +1452,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
out_unlock:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
mmput(mm);
if (!ret) {
/*
@@ -1496,7 +1498,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
if (!mmget_not_zero(mm))
goto out;
- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
vma = find_vma_prev(mm, start, &prev);
if (!vma)
goto out_unlock;
@@ -1609,7 +1611,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
out_unlock:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
mmput(mm);
out:
return ret;
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index f2f3b68ba910..35164358245f 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -64,7 +64,7 @@ extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
extern bool userfaultfd_remove(struct vm_area_struct *vma,
unsigned long start,
- unsigned long end);
+ unsigned long end, struct range_lock *mmrange);
extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
unsigned long start, unsigned long end,
@@ -120,7 +120,8 @@ static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
static inline bool userfaultfd_remove(struct vm_area_struct *vma,
unsigned long start,
- unsigned long end)
+ unsigned long end,
+ struct range_lock *mmrange)
{
return true;
}
diff --git a/mm/madvise.c b/mm/madvise.c
index de8fb035955c..9ba23187445b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -529,7 +529,7 @@ static long madvise_dontneed_free(struct vm_area_struct *vma,
if (!can_madv_dontneed_vma(vma))
return -EINVAL;
- if (!userfaultfd_remove(vma, start, end)) {
+ if (!userfaultfd_remove(vma, start, end, mmrange)) {
*prev = NULL; /* mmap_sem has been dropped, prev is stale */
mm_read_lock(current->mm, mmrange);
@@ -613,7 +613,7 @@ static long madvise_remove(struct vm_area_struct *vma,
* mmap_sem.
*/
get_file(f);
- if (userfaultfd_remove(vma, start, end)) {
+ if (userfaultfd_remove(vma, start, end, mmrange)) {
/* mmap_sem was not released by userfaultfd_remove() */
mm_read_unlock(current->mm, mmrange);
}
--
2.13.6