The patch titled
Subject: tmpfs: change shmem_mapping() to test shmem_aops
has been added to the -mm tree. Its filename is
tmpfs-change-shmem_mapping-to-test-shmem_aops.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/tmpfs-change-shmem_mapping-to-test-shmem_aops.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/tmpfs-change-shmem_mapping-to-test-shmem_aops.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: tmpfs: change shmem_mapping() to test shmem_aops
Callers of shmem_mapping() are interested in whether the mapping is swap
backed - except for uprobes, which is interested in whether it should use
shmem_read_mapping_page(). All these callers are better served by a
shmem_mapping() which checks for shmem_aops, than the current version
which goes through several indirections to find where the inode lives -
and has the surprising effect that a private mmap of /dev/zero satisfies
both vma_is_anonymous() and shmem_mapping(), when that device node is on
devtmpfs. I don't think anything in the tree suffers from that surprise,
but it caught me out, and is better fixed.
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1612052148530.13021@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff -puN mm/shmem.c~tmpfs-change-shmem_mapping-to-test-shmem_aops mm/shmem.c
--- a/mm/shmem.c~tmpfs-change-shmem_mapping-to-test-shmem_aops
+++ a/mm/shmem.c
@@ -2168,10 +2168,7 @@ static struct inode *shmem_get_inode(str
bool shmem_mapping(struct address_space *mapping)
{
- if (!mapping->host)
- return false;
-
- return mapping->host->i_sb->s_op == &shmem_ops;
+ return mapping->a_ops == &shmem_aops;
}
#ifdef CONFIG_TMPFS
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
tmpfs-change-shmem_mapping-to-test-shmem_aops.patch
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