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| author |   K. Y. Srinivasan <kys@microsoft.com> | 2016-01-27 22:29:45 -0800 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-07 21:34:12 -0800 |
| commit | fe760e4d64fe5c17c39e86c410d41f6587ee88bc (patch) | |
| tree | e25710bde0e1e4da9a127a3e6c449c08696c1940 /drivers/hv/ring_buffer.c | |
| parent | Drivers: hv: vmbus: Eliminate the spin lock on the read path (diff) | |
| download | linux-dev-fe760e4d64fe5c17c39e86c410d41f6587ee88bc.tar.xz linux-dev-fe760e4d64fe5c17c39e86c410d41f6587ee88bc.zip | |
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>
Diffstat (limited to 'drivers/hv/ring_buffer.c')
| -rw-r--r-- | drivers/hv/ring_buffer.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 1145f3b8e4e0..5613e2b5cff7 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -314,7 +314,7 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) /* 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 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, 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 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, * 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 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, 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; |