Drivers: hv: vmbus: Give control over how the ring access is serialized
On the channel send side, many of the VMBUS
device drivers explicity serialize access to the
outgoing ring buffer. Give more control to the
VMBUS device drivers in terms how to serialize
accesss to the outgoing ring buffer.
The default behavior will be to aquire the
ring lock to preserve the current behavior.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 1145f3b..5613e2b 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -314,7 +314,7 @@
/* Write to the ring buffer. */
int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
- struct kvec *kv_list, u32 kv_count, bool *signal)
+ struct kvec *kv_list, u32 kv_count, bool *signal, bool lock)
{
int i = 0;
u32 bytes_avail_towrite;
@@ -324,14 +324,15 @@
u32 next_write_location;
u32 old_write;
u64 prev_indices = 0;
- unsigned long flags;
+ unsigned long flags = 0;
for (i = 0; i < kv_count; i++)
totalbytes_towrite += kv_list[i].iov_len;
totalbytes_towrite += sizeof(u64);
- spin_lock_irqsave(&outring_info->ring_lock, flags);
+ if (lock)
+ spin_lock_irqsave(&outring_info->ring_lock, flags);
hv_get_ringbuffer_availbytes(outring_info,
&bytes_avail_toread,
@@ -343,7 +344,8 @@
* is empty since the read index == write index.
*/
if (bytes_avail_towrite <= totalbytes_towrite) {
- spin_unlock_irqrestore(&outring_info->ring_lock, flags);
+ if (lock)
+ spin_unlock_irqrestore(&outring_info->ring_lock, flags);
return -EAGAIN;
}
@@ -374,7 +376,8 @@
hv_set_next_write_location(outring_info, next_write_location);
- spin_unlock_irqrestore(&outring_info->ring_lock, flags);
+ if (lock)
+ spin_unlock_irqrestore(&outring_info->ring_lock, flags);
*signal = hv_need_to_signal(old_write, outring_info);
return 0;