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>
---
mm/nommu.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/mm/nommu.c b/mm/nommu.c
index 52a5765..cd519e1 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;
}
--
1.8.4.5
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