The patch titled
Subject: mm/nommu: share the i_mmap_rwsem
has been added to the -mm tree. Its filename is
mm-nommu-share-the-i_mmap_rwsem.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-nommu-share-the-i_mmap_rwsem.patch
echo and later at
echo http://ozlabs.org/~akpm/mmotm/broken-out/mm-nommu-share-the-i_mmap_rwsem.patch
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From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Subject: mm/nommu: share the i_mmap_rwsem
Shrinking/truncate logic can call nommu_shrink_inode_mappings() to verify
that any shared mappings of the inode in question aren't broken (dead
zone). afaict the only user being ramfs to handle the size change
attribute.
Pretty much a no-brainer to share the lock.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/nommu.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff -puN mm/nommu.c~mm-nommu-share-the-i_mmap_rwsem mm/nommu.c
--- a/mm/nommu.c~mm-nommu-share-the-i_mmap_rwsem
+++ a/mm/nommu.c
@@ -2094,14 +2094,14 @@ int nommu_shrink_inode_mappings(struct i
high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
down_write(&nommu_region_sem);
- i_mmap_lock_write(inode->i_mapping);
+ i_mmap_lock_read(inode->i_mapping);
/* search for VMAs that fall within the dead zone */
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
/* found one - only interested if it's shared out of the page
* cache */
if (vma->vm_flags & VM_SHARED) {
- i_mmap_unlock_write(inode->i_mapping);
+ i_mmap_unlock_read(inode->i_mapping);
up_write(&nommu_region_sem);
return -ETXTBSY; /* not quite true, but near enough */
}
@@ -2113,8 +2113,7 @@ int nommu_shrink_inode_mappings(struct i
* we don't check for any regions that start beyond the EOF as there
* shouldn't be any
*/
- vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap,
- 0, ULONG_MAX) {
+ vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
if (!(vma->vm_flags & VM_SHARED))
continue;
@@ -2129,7 +2128,7 @@ int nommu_shrink_inode_mappings(struct i
}
}
- i_mmap_unlock_write(inode->i_mapping);
+ i_mmap_unlock_read(inode->i_mapping);
up_write(&nommu_region_sem);
return 0;
}
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
mmfs-introduce-helpers-around-the-i_mmap_mutex.patch
mm-use-new-helper-functions-around-the-i_mmap_mutex.patch
mm-convert-i_mmap_mutex-to-rwsem.patch
mm-rmap-share-the-i_mmap_rwsem.patch
uprobes-share-the-i_mmap_rwsem.patch
mm-xip-share-the-i_mmap_rwsem.patch
mm-memory-failure-share-the-i_mmap_rwsem.patch
mm-nommu-share-the-i_mmap_rwsem.patch
ipc-semc-chance-memory-barrier-in-sem_lock-to-smp_rmb.patch
ipc-semc-chance-memory-barrier-in-sem_lock-to-smp_rmb-fix.patch
ipc-semc-chance-memory-barrier-in-sem_lock-to-smp_rmb-fix-fix.patch
ipc-semc-increase-semmsl-semmni-semopm.patch
ipc-msg-increase-msgmni-remove-scaling.patch
ipc-msg-increase-msgmni-remove-scaling-checkpatch-fixes.patch
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