From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Fri, 2 Sep 2016 12:58:21 +0000 (-0700)
Subject: Drivers: hv: ring_buffer: use wrap around mappings in hv_copy{from, to}_ringbuffer()
X-Git-Tag: v4.9-rc1~149^2~32
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f24f0b495b17df33c03f3b758b1461385e9f0e50;p=platform%2Fkernel%2Flinux-amlogic.git

Drivers: hv: ring_buffer: use wrap around mappings in hv_copy{from, to}_ringbuffer()

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

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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;