RTC: assure proper memory ordering with respect to RTC_DEV_BUSY flag
authorJiri Kosina <jkosina@suse.cz>
Wed, 5 Dec 2007 07:45:05 +0000 (23:45 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 5 Dec 2007 17:21:18 +0000 (09:21 -0800)
commit372a302e9a892229206aafca0352584a745bc5f3
tree14cf4e06735d8dd9284e843f36a5abcfcc4cc476
parent5cd17569fd0eeca510735e63a6061291e3971bf6
RTC: assure proper memory ordering with respect to RTC_DEV_BUSY flag

We must make sure that the RTC_DEV_BUSY flag has proper lock semantics,
i.e.  that the RTC_DEV_BUSY stores clearing the flag don't get reordered
before the preceeding stores and loads and vice versa.

Spotted by Nick Piggin.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/interface.c
drivers/rtc/rtc-dev.c