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authorJason Wang <jasowang@redhat.com>2013-06-18 13:04:23 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-18 11:14:18 -0700
commit35848f68b07df3f917cb13fc3c134718669f569b (patch)
tree6d098733bc0126ad5e133ff23d26caba0ed919e8 /drivers/hv/ring_buffer.c
parent36dd68319c7b56a76ed450b0e470067b5d74b9b2 (diff)
downloadlinux-35848f68b07df3f917cb13fc3c134718669f569b.tar.bz2
drivers: hv: switch to use mb() instead of smp_mb()
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 <jasowang@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv/ring_buffer.c')
-rw-r--r--drivers/hv/ring_buffer.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index d6fbb5772b8d..791f45dfc85d 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -32,7 +32,7 @@
void hv_begin_read(struct hv_ring_buffer_info *rbi)
{
rbi->ring_buffer->interrupt_mask = 1;
- smp_mb();
+ mb();
}
u32 hv_end_read(struct hv_ring_buffer_info *rbi)
@@ -41,7 +41,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
u32 write;
rbi->ring_buffer->interrupt_mask = 0;
- smp_mb();
+ mb();
/*
* Now check to see if the ring buffer is still empty.
@@ -71,7 +71,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
{
- smp_mb();
+ mb();
if (rbi->ring_buffer->interrupt_mask)
return false;
@@ -442,7 +442,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
sizeof(u64));
/* Issue a full memory barrier before updating the write index */
- smp_mb();
+ mb();
/* Now, update the write location */
hv_set_next_write_location(outring_info, next_write_location);
@@ -549,7 +549,7 @@ 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);