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>

5 files changed, 9 insertions, 34 deletions

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 18cc1c78260d..81a80c82f1bd 100644
--- a/drivers/hv/channel.c
+++ b/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);
 
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index b2bb5aafaa2f..f33465d78a02 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/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);
 
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 558a798c407c..6a9b54677218 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/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,
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 1b70e034ef92..1a1e70a45146 100644
--- a/drivers/hv/ring_buffer.c
+++ b/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);
 
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index e5aac5c051f7..466374dbc98f 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -846,16 +846,6 @@ struct vmbus_channel {
          */
         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
          * at the expense of latency:
@@ -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 &