linux-kernel - [PATCH 2/2] net: macb: kill useless use of list

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Message-ID: <20171205201830.GB18445@jcartwri.amer.corp.natinst.com>
Date:   Tue, 5 Dec 2017 14:18:30 -0600
From:   Julia Cartwright <julia@...com>
To:     Julia Lawall <julia.lawall@...6.fr>
CC:     Rafal Ozieblo <rafalo@...ence.com>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <kbuild-all@...org>
Subject: [PATCH 2/2] net: macb: kill useless use of list_empty()

The list_for_each_entry() macro already handles the case where the list
is empty (by not executing the loop body).  It's not necessary to handle
this case specially, so stop doing so.

Cc: Rafal Ozieblo <rafalo@...ence.com>
Signed-off-by: Julia Cartwright <julia@...com>
---
This is an additional cleanup patch found when looking at this code.

   Julia

 drivers/net/ethernet/cadence/macb_main.c | 34 ++++++++++++--------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index e7ef104a077d..3643c6ad2322 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -2815,25 +2815,22 @@ static int gem_add_flow_filter(struct net_device *netdev,
 	spin_lock_irqsave(&bp->rx_fs_lock, flags);
 
 	/* find correct place to add in list */
-	if (list_empty(&bp->rx_fs_list.list))
-		list_add(&newfs->list, &bp->rx_fs_list.list);
-	else {
-		list_for_each_entry(item, &bp->rx_fs_list.list, list) {
-			if (item->fs.location > newfs->fs.location) {
-				list_add_tail(&newfs->list, &item->list);
-				added = true;
-				break;
-			} else if (item->fs.location == fs->location) {
-				netdev_err(netdev, "Rule not added: location %d not free!\n",
-						fs->location);
-				ret = -EBUSY;
-				goto err;
-			}
+	list_for_each_entry(item, &bp->rx_fs_list.list, list) {
+		if (item->fs.location > newfs->fs.location) {
+			list_add_tail(&newfs->list, &item->list);
+			added = true;
+			break;
+		} else if (item->fs.location == fs->location) {
+			netdev_err(netdev, "Rule not added: location %d not free!\n",
+					fs->location);
+			ret = -EBUSY;
+			goto err;
 		}
-		if (!added)
-			list_add_tail(&newfs->list, &bp->rx_fs_list.list);
 	}
 
+	if (!added)
+		list_add_tail(&newfs->list, &bp->rx_fs_list.list);
+
 	gem_prog_cmp_regs(bp, fs);
 	bp->rx_fs_list.count++;
 	/* enable filtering if NTUPLE on */
@@ -2859,11 +2856,6 @@ static int gem_del_flow_filter(struct net_device *netdev,
 
 	spin_lock_irqsave(&bp->rx_fs_lock, flags);
 
-	if (list_empty(&bp->rx_fs_list.list)) {
-		spin_unlock_irqrestore(&bp->rx_fs_lock, flags);
-		return -EINVAL;
-	}
-
 	list_for_each_entry(item, &bp->rx_fs_list.list, list) {
 		if (item->fs.location == cmd->fs.location) {
 			/* disable screener regs for the flow entry */
-- 
2.14.2