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Drivers: hv: vmbus: Use READ_ONCE() to read variables that are volatile

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Use the READ_ONCE macro to access variabes that can change asynchronously.
This is the recommended mechanism for dealing with "unsafe" compiler
optimizations.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2016-04-02 17:59:47 -07:00 committed by Greg Kroah-Hartman
parent a6341f0000
commit d45faaeedb
1 changed files with 3 additions and 3 deletions
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6
drivers/hv/ring_buffer.c
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@ -69,7 +69,7 @@ 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)
{
mb();
if (rbi->ring_buffer->interrupt_mask)
if (READ_ONCE(rbi->ring_buffer->interrupt_mask))
return false;
/* check interrupt_mask before read_index */
@ -78,7 +78,7 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
* This is the only case we need to signal when the
* ring transitions from being empty to non-empty.
*/
if (old_write == rbi->ring_buffer->read_index)
if (old_write == READ_ONCE(rbi->ring_buffer->read_index))
return true;
return false;
@ -117,7 +117,7 @@ static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
*/
mb();
pending_sz = rbi->ring_buffer->pending_send_sz;
pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz);
/* If the other end is not blocked on write don't bother. */
if (pending_sz == 0)
return false;