tree f588998ccde75f23e1044f5fc636d134d9718c05
parent cf5b0208fda4602d0ef383a86e942fb3dcb8852b
author John Ogness <john.ogness@linutronix.de> 1614766521 +0100
committer Petr Mladek <pmladek@suse.com> 1615200195 +0100

printk: use seqcount_latch for clear_seq

kmsg_dump_rewind_nolock() locklessly reads @clear_seq. However,
this is not done atomically. Since @clear_seq is 64-bit, this
cannot be an atomic operation for all platforms. Therefore, use
a seqcount_latch to allow readers to always read a consistent
value.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-9-john.ogness@linutronix.de