Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1200442

[PATCH 05/13] Drivers: hv_vmbus: Fix signal to host condition

Show all headers | View raw

From: Christopher Oo <t-chriso@microsoft.com>

Fixes a bug where previously hv_ringbuffer_read would pass in the old
number of bytes available to read instead of the expected old read index
when calculating when to signal to the host that the ringbuffer is empty.
Since the previous write size is already saved, also changes the
hv_need_to_signal_on_read to use the previously read value rather than
recalculating it.

Signed-off-by: Christopher Oo <t-chriso@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/ring_buffer.c |   14 +++-----------
 1 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 6361d12..70a1a9a 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -103,10 +103,9 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
  *    there is room for the producer to send the pending packet.
  */
 
-static bool hv_need_to_signal_on_read(u32 old_rd,
-					 struct hv_ring_buffer_info *rbi)
+static bool hv_need_to_signal_on_read(u32 prev_write_sz,
+				      struct hv_ring_buffer_info *rbi)
 {
-	u32 prev_write_sz;
 	u32 cur_write_sz;
 	u32 r_size;
 	u32 write_loc = rbi->ring_buffer->write_index;
@@ -123,10 +122,6 @@ static bool hv_need_to_signal_on_read(u32 old_rd,
 	cur_write_sz = write_loc >= read_loc ? r_size - (write_loc - read_loc) :
 			read_loc - write_loc;
 
-	prev_write_sz = write_loc >= old_rd ? r_size - (write_loc - old_rd) :
-			old_rd - write_loc;
-
-
 	if ((prev_write_sz < pending_sz) && (cur_write_sz >= pending_sz))
 		return true;
 
@@ -517,7 +512,6 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
 	u32 next_read_location = 0;
 	u64 prev_indices = 0;
 	unsigned long flags;
-	u32 old_read;
 
 	if (buflen <= 0)
 		return -EINVAL;
@@ -528,8 +522,6 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
 				&bytes_avail_toread,
 				&bytes_avail_towrite);
 
-	old_read = bytes_avail_toread;
-
 	/* Make sure there is something to read */
 	if (bytes_avail_toread < buflen) {
 		spin_unlock_irqrestore(&inring_info->ring_lock, flags);
@@ -560,7 +552,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
 
 	spin_unlock_irqrestore(&inring_info->ring_lock, flags);
 
-	*signal = hv_need_to_signal_on_read(old_read, inring_info);
+	*signal = hv_need_to_signal_on_read(bytes_avail_towrite, inring_info);
 
 	return 0;
 }
-- 
1.7.4.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 00/13] Drivers: hv: vmbus: Miscellaneous fixes  "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:30 +0200
  [PATCH 08/13] Drivers: hv: vmbus: add a sysfs attr to show the binding of channel/VP "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:30 +0200
  RE: [PATCH 00/13] Drivers: hv: vmbus: Miscellaneous fixes  KY Srinivasan <kys@microsoft.com> - 2015-08-05 08:30 +0200
  [PATCH 13/13] Drivers: hv: vmbus: use cpu_hotplug_enable/disable "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:30 +0200
  [PATCH 11/13] cpu-hotplug: convert cpu_hotplug_disabled to a counter "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:30 +0200
  [PATCH 05/13] Drivers: hv_vmbus: Fix signal to host condition "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:40 +0200
  [PATCH 07/13] Drivers: hv: vmbus: Implement a clocksource based on the TSC page "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:40 +0200
  [PATCH 12/13] cpu-hotplug: export cpu_hotplug_enable/cpu_hotplug_disable "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:40 +0200
  [PATCH 01/13] drivers:hv: Modify hv_vmbus to search for all MMIO ranges available. "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:40 +0200
    [PATCH 03/13] Drivers: hv: vmbus: Improve the CPU affiliation for channels "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 08:40 +0200
    [PATCH 09/13] tools: hv: add a python script lsvmbus to list VMBus devices "K. Y. Srinivasan" <kys@microsoft.com> - 2015-08-05 09:00 +0200

csiph-web