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| author | Davidlohr Bueso <dave@stgolabs.net> | 2014-12-12 16:54:39 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-13 12:42:46 -0800 |
| commit | 1acf2e040721564d579297646862b8ea3dd4511b (patch) | |
| tree | c51ec6206f123b9d09caed4878d4958314d497db /mm/nommu.c | |
| parent | d28eb9c861f41aa2af4cfcc5eeeddff42b13d31e (diff) | |
| download | lwn-1acf2e040721564d579297646862b8ea3dd4511b.tar.gz lwn-1acf2e040721564d579297646862b8ea3dd4511b.zip | |
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@suse.de>
Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/nommu.c')
| -rw-r--r-- | mm/nommu.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/mm/nommu.c b/mm/nommu.c index 52a576553581..cd519e1cd8a7 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -2094,14 +2094,14 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size, 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 inode *inode, size_t size, * 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 inode *inode, size_t size, } } - i_mmap_unlock_write(inode->i_mapping); + i_mmap_unlock_read(inode->i_mapping); up_write(&nommu_region_sem); return 0; } |