tree de2f029495110336d2dd2b89205db2c62710dd50
parent 6d24c8dc2e656b02807aa0506405727d34c0376c
author Al Viro <viro@ftp.linux.org.uk> 1160314335 +0100
committer Linus Torvalds <torvalds@g5.osdl.org> 1160335955 -0700

[PATCH] sparc32 rwlock fix

read_trylock() is broken on sparc32 (doesn't build and didn't work
right, actually).  Proposed fix:

 - make "writer holds lock" distinguishable from "reader tries to grab
   lock"

 - have __raw_read_trylock() try to acquire the mutex (in LSB of lock),
   terminating spin if we see that there's writer holding it.  Then do
   the rest as we do in read_lock().

Thanks to Ingo for discussion...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>