Commit 35848f68 authored by Jason Wang's avatar Jason Wang Committed by Greg Kroah-Hartman
Browse files

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: default avatarJason Wang <jasowang@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 36dd6831

drivers/hv/ring_buffer.c

+5 −5
Original line number Diff line number Diff line
@@ -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);

drivers/hv/vmbus_drv.c

+1 −1
Original line number Diff line number Diff line
@@ -434,7 +434,7 @@ 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) {

			/*

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