[PATCH 3/4] Drivers: hv: ring_buffer: use wrap around mappings in hv_copy{from,to}_ringbuffer()

[kys]

From: Vitaly Kuznetsov <vkuzn...@redhat.com>

With wrap around mappings for ring buffers we can always use a single
memcpy() to do the job.

Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
Tested-by: Dexuan Cui <de...@microsoft.com>
---
 drivers/hv/ring_buffer.c |   24 +++---------------------
 1 files changed, 3 insertions(+), 21 deletions(-)

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 7e21c2c..08043da 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -172,18 +172,7 @@ static u32 hv_copyfrom_ringbuffer(
        void *ring_buffer = hv_get_ring_buffer(ring_info);
        u32 ring_buffer_size = hv_get_ring_buffersize(ring_info);
 
-       u32 frag_len;
-
-       /* wrap-around detected at the src */
-       if (destlen > ring_buffer_size - start_read_offset) {
-               frag_len = ring_buffer_size - start_read_offset;
-
-               memcpy(dest, ring_buffer + start_read_offset, frag_len);
-               memcpy(dest + frag_len, ring_buffer, destlen - frag_len);
-       } else
-
-               memcpy(dest, ring_buffer + start_read_offset, destlen);
-
+       memcpy(dest, ring_buffer + start_read_offset, destlen);
 
        start_read_offset += destlen;
        start_read_offset %= ring_buffer_size;
@@ -204,15 +193,8 @@ static u32 hv_copyto_ringbuffer(
 {
        void *ring_buffer = hv_get_ring_buffer(ring_info);
        u32 ring_buffer_size = hv_get_ring_buffersize(ring_info);
-       u32 frag_len;
-
-       /* wrap-around detected! */
-       if (srclen > ring_buffer_size - start_write_offset) {
-               frag_len = ring_buffer_size - start_write_offset;
-               memcpy(ring_buffer + start_write_offset, src, frag_len);
-               memcpy(ring_buffer, src + frag_len, srclen - frag_len);
-       } else
-               memcpy(ring_buffer + start_write_offset, src, srclen);
+
+       memcpy(ring_buffer + start_write_offset, src, srclen);
 
        start_write_offset += srclen;
        start_write_offset %= ring_buffer_size;
-- 
1.7.4.1