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| author | Stephen Hemminger <stephen@networkplumber.org> | 2017-12-01 11:01:49 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-03 10:10:02 -0500 |
| commit | 0487426fedf7cf800115bac7ea391de1e2e0fa5f (patch) | |
| tree | f09b1169817849c0c1d2ae71524465bf5cdef428 /drivers/hv/ring_buffer.c | |
| parent | f5a2255010b0bde6df5a9060dbc826ad14ad4c44 (diff) | |
| download | linux-0487426fedf7cf800115bac7ea391de1e2e0fa5f.tar.gz linux-0487426fedf7cf800115bac7ea391de1e2e0fa5f.tar.bz2 linux-0487426fedf7cf800115bac7ea391de1e2e0fa5f.zip | |
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.c | 23 |
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) |