diff options
| author | Hugh Dickins <hughd@google.com> | 2017-02-22 15:41:42 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 16:41:27 -0800 |
| commit | f8005451d75f4879a93b12c14b162dd60f81ec56 (patch) | |
| tree | 59ea91b6fd31565cdcd424249172bfea1852c0d0 | |
| parent | 1663f26df3df7df3720306ca67f5ea8296d68fa1 (diff) | |
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@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/shmem.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 3a7587a0314d..7d52cd4b504d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2175,10 +2175,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode 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 |