From: Davidlohr Bueso <d...@stgolabs.net> 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 <dbu...@suse.de> Acked-by: "Kirill A. Shutemov" <kir...@shutemov.name> Acked-by: Hugh Dickins <hu...@google.com> Cc: Oleg Nesterov <o...@redhat.com> Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Rik van Riel <r...@redhat.com> Cc: Srikar Dronamraju <sri...@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgor...@suse.de> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-122663 (cherry picked from commit 1acf2e040721564d579297646862b8ea3dd4511b) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- mm/nommu.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/mm/nommu.c b/mm/nommu.c index f994621e52f0..290fe3031147 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -2134,14 +2134,14 @@ 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 */ } @@ -2153,8 +2153,7 @@ 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; @@ -2169,7 +2168,7 @@ 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; } -- 2.26.2 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
