linux-kernel - [PATCH] virtio_ring: Optimize duplicate judgment codes for virtqueue_add

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Date:   Mon, 20 Jun 2022 04:06:56 -0400
From:   Deming Wang <wangdeming@...pur.com>
To:     <mst@...hat.com>, <jasowang@...hat.com>
CC:     <virtualization@...ts.linux-foundation.org>,
        <linux-kernel@...r.kernel.org>, Deming Wang <wangdeming@...pur.com>
Subject: [PATCH] virtio_ring: Optimize duplicate judgment codes for virtqueue_add_split

We combine repeated judgments about indirect in one place

Signed-off-by: Deming Wang <wangdeming@...pur.com>
---
 drivers/virtio/virtio_ring.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 13a7348cedff..331fa3cf5be7 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -582,23 +582,19 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 					 total_sg * sizeof(struct vring_desc),
 					 VRING_DESC_F_INDIRECT,
 					 false);
+		vq->free_head = vq->split.desc_extra[head].next;
+		vq->split.desc_state[head].indir_desc = desc;
+	} else {
+		/* Update free pointer */
+		vq->free_head = i;
+		vq->split.desc_state[head].indir_desc = ctx;
 	}
 
 	/* We're using some buffers from the free list. */
 	vq->vq.num_free -= descs_used;
 
-	/* Update free pointer */
-	if (indirect)
-		vq->free_head = vq->split.desc_extra[head].next;
-	else
-		vq->free_head = i;
-
 	/* Store token and indirect buffer state. */
 	vq->split.desc_state[head].data = data;
-	if (indirect)
-		vq->split.desc_state[head].indir_desc = desc;
-	else
-		vq->split.desc_state[head].indir_desc = ctx;
 
 	/* Put entry in available array (but don't update avail->idx until they
 	 * do sync). */
-- 
2.27.0