Commit 8d12f882 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Greg Kroah-Hartman
Browse files

vmbus: replace modulus operation with subtraction 



Takes less clock cycles to check for ring wrap and subtract than to
do a modulus instruction.

Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e4165a0f

drivers/hv/ring_buffer.c

+6 −3
Original line number Diff line number Diff line
@@ -112,7 +112,8 @@ hv_get_next_readlocation_withoffset(const struct hv_ring_buffer_info *ring_info, 
	u32 next = ring_info->ring_buffer->read_index;



	next += offset;

	next %= ring_info->ring_datasize;

	if (next >= ring_info->ring_datasize)

		next -= ring_info->ring_datasize;



	return next;

}
@@ -156,7 +157,8 @@ static u32 hv_copyfrom_ringbuffer( 
	memcpy(dest, ring_buffer + start_read_offset, destlen);



	start_read_offset += destlen;

	start_read_offset %= ring_buffer_size;

	if (start_read_offset >= ring_buffer_size)

		start_read_offset -= ring_buffer_size;



	return start_read_offset;

}
@@ -178,7 +180,8 @@ static u32 hv_copyto_ringbuffer( 
	memcpy(ring_buffer + start_write_offset, src, srclen);



	start_write_offset += srclen;

	start_write_offset %= ring_buffer_size;

	if (start_write_offset >= ring_buffer_size)

		start_write_offset -= ring_buffer_size;



	return start_write_offset;

}

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