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authorJohn Stultz <john.stultz@linaro.org>2013-10-07 15:51:59 -0700
committerIngo Molnar <mingo@kernel.org>2013-11-06 12:40:26 +0100
commit1ca7d67cf5d5a2aef26a8d9afd789006fa098347 (patch)
tree8f4f7d1f189d7a08983ab5ef522330f08f337459 /mm/filemap_xip.c
parent827da44c61419f29ae3be198c342e2147f1a10cb (diff)
downloadlinux-1ca7d67cf5d5a2aef26a8d9afd789006fa098347.tar.gz
seqcount: Add lockdep functionality to seqcount/seqlock structures
Currently seqlocks and seqcounts don't support lockdep. After running across a seqcount related deadlock in the timekeeping code, I used a less-refined and more focused variant of this patch to narrow down the cause of the issue. This is a first-pass attempt to properly enable lockdep functionality on seqlocks and seqcounts. Since seqcounts are used in the vdso gettimeofday code, I've provided non-lockdep accessors for those needs. I've also handled one case where there were nested seqlock writers and there may be more edge cases. Comments and feedback would be appreciated! Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/1381186321-4906-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/filemap_xip.c')
-rw-r--r--mm/filemap_xip.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 28fe26b64f8..d8d9fe3f685 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -26,7 +26,7 @@
* of ZERO_PAGE(), such as /dev/zero
*/
static DEFINE_MUTEX(xip_sparse_mutex);
-static seqcount_t xip_sparse_seq = SEQCNT_ZERO;
+static seqcount_t xip_sparse_seq = SEQCNT_ZERO(xip_sparse_seq);
static struct page *__xip_sparse_page;
/* called under xip_sparse_mutex */