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authorStephen Hemminger <stephen@networkplumber.org>2017-12-01 11:01:49 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-03 10:10:02 -0500
commit0487426fedf7cf800115bac7ea391de1e2e0fa5f (patch)
treef09b1169817849c0c1d2ae71524465bf5cdef428 /drivers/hv/ring_buffer.c
parentf5a2255010b0bde6df5a9060dbc826ad14ad4c44 (diff)
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vmbus: make hv_get_ringbuffer_availbytes local
The last use of hv_get_ringbuffer_availbytes in drivers is now gone. Only used by the debug info routine so make it static. Also, add READ_ONCE() to avoid any possible issues with potentially volatile index values. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/hv/ring_buffer.c')
-rw-r--r--drivers/hv/ring_buffer.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 12eb8caa4263..50e071444a5c 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -140,6 +140,29 @@ static u32 hv_copyto_ringbuffer(
return start_write_offset;
}
+/*
+ *
+ * hv_get_ringbuffer_availbytes()
+ *
+ * Get number of bytes available to read and to write to
+ * for the specified ring buffer
+ */
+static void
+hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
+ u32 *read, u32 *write)
+{
+ u32 read_loc, write_loc, dsize;
+
+ /* Capture the read/write indices before they changed */
+ read_loc = READ_ONCE(rbi->ring_buffer->read_index);
+ write_loc = READ_ONCE(rbi->ring_buffer->write_index);
+ dsize = rbi->ring_datasize;
+
+ *write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
+ read_loc - write_loc;
+ *read = dsize - *write;
+}
+
/* Get various debug metrics for the specified ring buffer. */
void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
struct hv_ring_buffer_debug_info *debug_info)