tmpfs: enable NOSEC optimization

Hugh Dickins · torvalds · commit 2f6e38f3cd17 · 2012-05-29T16:22:22.000-07:00
Let tmpfs into the NOSEC optimization (avoiding file_remove_suid()
overhead on most common writes): set MS_NOSEC on its superblocks.

Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Cc: Andi Kleen &lt;andi@firstfloor.org&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
diff --git a/mm/shmem.c b/mm/shmem.c
@@ -2373,6 +2373,7 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent)
 		}
 	}
 	sb->s_export_op = &shmem_export_ops;
+	sb->s_flags |= MS_NOSEC;
 #else
 	sb->s_flags |= MS_NOUSER;
 #endif

Original file line number	Diff line number	Diff line change
`@@ -2373,6 +2373,7 @@ int shmem_fill_super(struct super_block sb, void data, int silent)`
`2373`	`2373`	`}`
`2374`	`2374`	`}`
`2375`	`2375`	`sb->s_export_op = &shmem_export_ops;`
	`2376`	`+ sb->s_flags \|= MS_NOSEC;`
`2376`	`2377`	`#else`
`2377`	`2378`	`sb->s_flags \|= MS_NOUSER;`
`2378`	`2379`	`#endif`