Commit-ID: ef8ac06359ddf95431cf6bb04ad2b36fff562328 Gitweb: http://git.kernel.org/tip/ef8ac06359ddf95431cf6bb04ad2b36fff562328 Author: Rik van Riel <[email protected]> AuthorDate: Fri, 12 Sep 2014 09:12:14 -0400 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 19 Sep 2014 12:35:16 +0200
seqlock: Add irqsave variant of read_seqbegin_or_lock() There are cases where read_seqbegin_or_lock() needs to block irqs, because the seqlock in question nests inside a lock that is also be taken from irq context. Add read_seqbegin_or_lock_irqsave() and done_seqretry_irqrestore(), which are almost identical to read_seqbegin_or_lock() and done_seqretry(). Signed-off-by: Rik van Riel <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Al Viro <[email protected]> Cc: John Stultz <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Stephen Boyd <[email protected]> Cc: Trond Myklebust <[email protected]> Link: http://lkml.kernel.org/r/[email protected] [ Improved the readability of the code a bit. ] Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/seqlock.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index cc35963..f5df8f6 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -456,4 +456,23 @@ read_sequnlock_excl_irqrestore(seqlock_t *sl, unsigned long flags) spin_unlock_irqrestore(&sl->lock, flags); } +static inline unsigned long +read_seqbegin_or_lock_irqsave(seqlock_t *lock, int *seq) +{ + unsigned long flags = 0; + + if (!(*seq & 1)) /* Even */ + *seq = read_seqbegin(lock); + else /* Odd */ + read_seqlock_excl_irqsave(lock, flags); + + return flags; +} + +static inline void +done_seqretry_irqrestore(seqlock_t *lock, int seq, unsigned long flags) +{ + if (seq & 1) + read_sequnlock_excl_irqrestore(lock, flags); +} #endif /* __LINUX_SEQLOCK_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
