From: Davidlohr Bueso Date: Tue, 30 Jun 2015 21:58:39 +0000 (-0700) Subject: ipc,msg: provide barrier pairings for lockless receive X-Git-Tag: omap-for-v4.2/fixes-rc1^2~53^2~29 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff35e5ef86fea1fa84eb7fdc939d0b1e3f1222bf;p=pandora-kernel.git ipc,msg: provide barrier pairings for lockless receive We currently use a full barrier on the sender side to to avoid receiver tasks disappearing on us while still performing on the sender side wakeup. We lack however, the proper CPU-CPU interactions pairing on the receiver side which busy-waits for the message. Similarly, we do not need a full smp_mb, and can relax the semantics for the writer and reader sides of the message. This is safe as we are only ordering loads and stores to r_msg. And in both smp_wmb and smp_rmb, there are no stores after the calls _anyway_. This obviously applies for pipelined_send and expunge_all, for EIRDM when destroying a queue. Signed-off-by: Davidlohr Bueso Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed