Messages in this thread | | | Date | Tue, 28 Jan 2014 13:53:16 +0200 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH] mm: readahead: fix do_readahead for no readpage(s) |
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On Tue, Jan 28, 2014 at 11:14:19AM +0000, Mark Rutland wrote: > Commit 63d0f0a3c7e1 (mm/readahead.c:do_readhead(): don't check for > ->readpage) unintentionally made do_readahead return 0 for all valid > files regardless of whether readahead was supported, rather than the > expected -EINVAL. This gets forwarded on to userspace, and results in > sys_readahead appearing to succeed in cases that don't make sense (e.g. > when called on pipes or sockets). This issue is detected by the LTP > readahead01 testcase. > > As the exact return value of force_page_cache_readahead is currently > never used, we can simplify it to return only 0 or -EINVAL (when > readpage or readpages is missing). With that in place we can simply > forward on the return value of force_page_cache_readahead in > do_readahead. > > This patch performs said change, restoring the expected semantics. > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
-- Kirill A. Shutemov
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