From: Jason Wang Date: Tue, 18 Jun 2013 05:04:23 +0000 (+0800) Subject: drivers: hv: switch to use mb() instead of smp_mb() X-Git-Tag: v3.4.92~64 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4f9e14fad5e381e075f942677e9c1ae70e0f186e;p=thirdparty%2Fkernel%2Fstable.git drivers: hv: switch to use mb() instead of smp_mb() commit 35848f68b07df3f917cb13fc3c134718669f569b upstream. Even if guest were compiled without SMP support, it could not assume that host wasn't. So switch to use mb() instead of smp_mb() to force memory barriers for UP guest. Signed-off-by: Jason Wang Cc: Haiyang Zhang Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: - Drop changes to functions that don't exist here - hv_ringbuffer_write() has only a write memory barrier] Signed-off-by: Ben Hutchings [hq: Backported to 3.4: - Add the change in hv_ringbuffer_read] Signed-off-by: Qiang Huang Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 8af25a097d75a..d01edf3c7b286 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -383,7 +383,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, sizeof(u64)); /* Make sure we flush all writes before updating the writeIndex */ - smp_wmb(); + wmb(); /* Now, update the write location */ hv_set_next_write_location(outring_info, next_write_location); @@ -485,7 +485,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, /* Make sure all reads are done before we update the read index since */ /* the writer may start writing to the read area once the read index */ /*is updated */ - smp_mb(); + mb(); /* Update the read index */ hv_set_next_read_location(inring_info, next_read_location); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index a220e5746d67d..10619b34bd318 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -466,7 +466,7 @@ static void vmbus_on_msg_dpc(unsigned long data) * will not deliver any more messages since there is * no empty slot */ - smp_mb(); + mb(); if (msg->header.message_flags.msg_pending) { /*