vmbus: remove conditional locking of vmbus_write

All current usage of vmbus write uses the acquire_lock flag, therefore
having it be optional is unnecessary. This also fixes a sparse warning
since sparse doesn't like when a function has conditional locking.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/channel.c

@@ -651,7 +651,6 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
 	u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 	struct kvec bufferlist[3];
 	u64 aligned_data = 0;
-	bool lock = channel->acquire_ring_lock;
 	int num_vecs = ((bufferlen != 0) ? 3 : 1);
 
 
@@ -670,7 +669,7 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
 	bufferlist[2].iov_base = &aligned_data;
 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 
-	return hv_ringbuffer_write(channel, bufferlist, num_vecs, lock);
+	return hv_ringbuffer_write(channel, bufferlist, num_vecs);
 }
 EXPORT_SYMBOL(vmbus_sendpacket_ctl);
 
@@ -716,12 +715,10 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
 	u32 packetlen_aligned;
 	struct kvec bufferlist[3];
 	u64 aligned_data = 0;
-	bool lock = channel->acquire_ring_lock;
 
 	if (pagecount > MAX_PAGE_BUFFER_COUNT)
 		return -EINVAL;
 
-
 	/*
 	 * Adjust the size down since vmbus_channel_packet_page_buffer is the
 	 * largest size we support
@@ -753,7 +750,7 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
 	bufferlist[2].iov_base = &aligned_data;
 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 
-	return hv_ringbuffer_write(channel, bufferlist, 3, lock);
+	return hv_ringbuffer_write(channel, bufferlist, 3);
 }
 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl);
 
@@ -789,7 +786,6 @@ int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 	u32 packetlen_aligned;
 	struct kvec bufferlist[3];
 	u64 aligned_data = 0;
-	bool lock = channel->acquire_ring_lock;
 
 	packetlen = desc_size + bufferlen;
 	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
@@ -809,7 +805,7 @@ int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 	bufferlist[2].iov_base = &aligned_data;
 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 
-	return hv_ringbuffer_write(channel, bufferlist, 3, lock);
+	return hv_ringbuffer_write(channel, bufferlist, 3);
 }
 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 
@@ -827,7 +823,6 @@ int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 	u32 packetlen_aligned;
 	struct kvec bufferlist[3];
 	u64 aligned_data = 0;
-	bool lock = channel->acquire_ring_lock;
 	u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 					 multi_pagebuffer->len);
 
@@ -866,7 +861,7 @@ int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 	bufferlist[2].iov_base = &aligned_data;
 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 
-	return hv_ringbuffer_write(channel, bufferlist, 3, lock);
+	return hv_ringbuffer_write(channel, bufferlist, 3);
 }
 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 

drivers/hv/channel_mgmt.c

@@ -332,7 +332,6 @@ static struct vmbus_channel *alloc_channel(void)
 	if (!channel)
 		return NULL;
 
-	channel->acquire_ring_lock = true;
 	spin_lock_init(&channel->inbound_lock);
 	spin_lock_init(&channel->lock);
 

drivers/hv/hyperv_vmbus.h

@@ -283,8 +283,7 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
 void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
 
 int hv_ringbuffer_write(struct vmbus_channel *channel,
-			struct kvec *kv_list,
-			u32 kv_count, bool lock);
+			struct kvec *kv_list, u32 kv_count);
 
 int hv_ringbuffer_read(struct vmbus_channel *channel,
 		       void *buffer, u32 buflen, u32 *buffer_actual_len,

drivers/hv/ring_buffer.c

@@ -284,7 +284,7 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info)
 
 /* Write to the ring buffer. */
 int hv_ringbuffer_write(struct vmbus_channel *channel,
-			struct kvec *kv_list, u32 kv_count, bool lock)
+			struct kvec *kv_list, u32 kv_count)
 {
 	int i = 0;
 	u32 bytes_avail_towrite;
@@ -304,8 +304,7 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
 
 	totalbytes_towrite += sizeof(u64);
 
-	if (lock)
-		spin_lock_irqsave(&outring_info->ring_lock, flags);
+	spin_lock_irqsave(&outring_info->ring_lock, flags);
 
 	bytes_avail_towrite = hv_get_bytes_to_write(outring_info);
 
@@ -315,8 +314,7 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
 	 * is empty since the read index == write index.
 	 */
 	if (bytes_avail_towrite <= totalbytes_towrite) {
-		if (lock)
-			spin_unlock_irqrestore(&outring_info->ring_lock, flags);
+		spin_unlock_irqrestore(&outring_info->ring_lock, flags);
 		return -EAGAIN;
 	}
 
@@ -347,8 +345,7 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
 	hv_set_next_write_location(outring_info, next_write_location);
 
 
-	if (lock)
-		spin_unlock_irqrestore(&outring_info->ring_lock, flags);
+	spin_unlock_irqrestore(&outring_info->ring_lock, flags);
 
 	hv_signal_on_write(old_write, channel);
 

include/linux/hyperv.h

@@ -845,16 +845,6 @@ struct vmbus_channel {
 	 * link up channels based on their CPU affinity.
 	 */
 	struct list_head percpu_list;
-	/*
-	 * 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.
-	 */
-	bool acquire_ring_lock;
 	/*
 	 * For performance critical channels (storage, networking
 	 * etc,), Hyper-V has a mechanism to enhance the throughput
@@ -895,11 +885,6 @@ struct vmbus_channel {
 
 };
 
-static inline void set_channel_lock_state(struct vmbus_channel *c, bool state)
-{
-	c->acquire_ring_lock = state;
-}
-
 static inline bool is_hvsock_channel(const struct vmbus_channel *c)
 {
 	return !!(c->offermsg.offer.chn_flags &