rwsem: fully separate code paths to wake writers vs readers
authorMichel Lespinasse <walken@google.com>
Tue, 10 Aug 2010 00:21:15 +0000 (17:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 10 Aug 2010 03:45:10 +0000 (20:45 -0700)
commit345af7bf3304410634c21ada4664fda83d4d9a16
tree1fd8b49ef79796e561cce19794af371099f5e7ca
parent7721fea3d0fd93fb4d000eb737b444369358d6d3
rwsem: fully separate code paths to wake writers vs readers

This is in preparation for later changes in the series.

In __rwsem_do_wake(), the first queued waiter is checked first in order to
determine whether it's a writer or a reader.  The code paths diverge at
this point.  The code that checks and increments the rwsem active count is
duplicated on both sides - the point is that later changes in the series
will be able to independently modify both sides.

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Mike Waychison <mikew@google.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Ying Han <yinghan@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/rwsem.c