From 1ca7d67cf5d5a2aef26a8d9afd789006fa098347 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 7 Oct 2013 15:51:59 -0700 Subject: 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 Signed-off-by: Peter Zijlstra Cc: Eric Dumazet Cc: Li Zefan Cc: Mathieu Desnoyers Cc: Steven Rostedt Cc: "David S. Miller" 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 --- mm/filemap_xip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index 28fe26b64f8a..d8d9fe3f685c 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 */ -- cgit v1.2.3