netdev - [PATCH net-next] virtio-net: drop rq->max and rq->num

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1389854724-48411-1-git-send-email-jasowang@redhat.com>
Date:	Thu, 16 Jan 2014 14:45:24 +0800
From:	Jason Wang <jasowang@...hat.com>
To:	davem@...emloft.net, virtualization@...ts.linux-foundation.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Jason Wang <jasowang@...hat.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	"Michael S. Tsirkin" <mst@...hat.com>
Subject: [PATCH net-next] virtio-net: drop rq->max and rq->num

It looks like there's no need for those two fields:

- Unless there's a failure for the first refill try, rq->max should be always
  equal to the vring size.
- rq->num is only used to determine the condition that we need to do the refill,
  we could check vq->num_free instead.
- rq->num was required to be increased or decreased explicitly after each
  get/put which results a bad API.

So this patch removes them both to make the code simpler.

Cc: Rusty Russell <rusty@...tcorp.com.au>
Cc: Michael S. Tsirkin <mst@...hat.com>
Signed-off-by: Jason Wang <jasowang@...hat.com>
Acked-by: Rusty Russell <rusty@...tcorp.com.au>
---
 drivers/net/virtio_net.c |   16 +++-------------
 1 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7b17240..9bd70aa 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -72,9 +72,6 @@ struct receive_queue {
 
 	struct napi_struct napi;
 
-	/* Number of input buffers, and max we've ever had. */
-	unsigned int num, max;
-
 	/* Chain pages by the private ptr. */
 	struct page *pages;
 
@@ -360,7 +357,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 		}
 
 		page = virt_to_head_page(buf);
-		--rq->num;
 
 		num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
 		if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
@@ -406,7 +402,6 @@ err_skb:
 		}
 		page = virt_to_head_page(buf);
 		put_page(page);
-		--rq->num;
 	}
 err_buf:
 	dev->stats.rx_dropped++;
@@ -628,10 +623,7 @@ static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
 		oom = err == -ENOMEM;
 		if (err)
 			break;
-		++rq->num;
 	} while (rq->vq->num_free);
-	if (unlikely(rq->num > rq->max))
-		rq->max = rq->num;
 	if (unlikely(!virtqueue_kick(rq->vq)))
 		return false;
 	return !oom;
@@ -699,11 +691,10 @@ again:
 	while (received < budget &&
 	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
 		receive_buf(rq, buf, len);
-		--rq->num;
 		received++;
 	}
 
-	if (rq->num < rq->max / 2) {
+	if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
 		if (!try_fill_recv(rq, GFP_ATOMIC))
 			schedule_delayed_work(&vi->refill, 0);
 	}
@@ -1398,9 +1389,7 @@ static void free_unused_bufs(struct virtnet_info *vi)
 				give_pages(&vi->rq[i], buf);
 			else
 				dev_kfree_skb(buf);
-			--vi->rq[i].num;
 		}
-		BUG_ON(vi->rq[i].num != 0);
 	}
 }
 
@@ -1671,7 +1660,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 		try_fill_recv(&vi->rq[i], GFP_KERNEL);
 
 		/* If we didn't even get one input buffer, we're useless. */
-		if (vi->rq[i].num == 0) {
+		if (vi->rq[i].vq->num_free ==
+		    virtqueue_get_vring_size(vi->rq[i].vq)) {
 			free_unused_bufs(vi);
 			err = -ENOMEM;
 			goto free_recv_bufs;
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html