Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates
 216.228.117.160 as permitted sender) receiver=protection.outlook.com;
 client-ip=216.228.117.160; helo=mail.nvidia.com; pr=C
From:   Chaitanya Kulkarni <kch@nvidia.com>
To:     <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <axboe@kernel.dk>, <kch@nvidia.com>,
        <damien.lemoal@opensource.wdc.com>, <johannes.thumshirn@wdc.com>,
        <bvanassche@acm.org>, <ming.lei@redhat.com>,
        <shinichiro.kawasaki@wdc.com>, <vincent.fu@samsung.com>,
        <yukuai3@huawei.com>
Subject: [PATCH 5/6] null_blk: don't use magic numbers in the code
Date:   Tue, 4 Oct 2022 20:17:00 -0700
Message-ID: <20221005031701.79077-6-kch@nvidia.com>
In-Reply-To: <20221005031701.79077-1-kch@nvidia.com>
References: <20221005031701.79077-1-kch@nvidia.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Oct 2022 03:18:19.8869
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 6e5a69a4-9459-40d0-559e-08daa68040d3
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com]
X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT010.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4370
X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,
        RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_NONE
        autolearn=no autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Insteasd of using the hardcoded value use meaningful macro for tag
available value of -1U in get_tag() and __alloc_cmd().

While at it return early on error to get rid of the extra indentation
in __alloc_cmd().

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
---
 drivers/block/null_blk/main.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 765c1ca0edf5..eda5050d6dee 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -24,6 +24,8 @@
 #define TICKS_PER_SEC		50ULL
 #define TIMER_INTERVAL		(NSEC_PER_SEC / TICKS_PER_SEC)
 
+#define NULL_REQ_TAG_NOT_AVAILABLE (-1U)
+
 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
 static DECLARE_FAULT_ATTR(null_timeout_attr);
 static DECLARE_FAULT_ATTR(null_requeue_attr);
@@ -730,7 +732,7 @@ static unsigned int get_tag(struct nullb_queue *nq)
 	do {
 		tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
 		if (tag >= nq->queue_depth)
-			return -1U;
+			return NULL_REQ_TAG_NOT_AVAILABLE;
 	} while (test_and_set_bit_lock(tag, nq->tag_map));
 
 	return tag;
@@ -749,21 +751,19 @@ static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq, struct bio *bio)
 	unsigned int tag;
 
 	tag = get_tag(nq);
-	if (tag != -1U) {
-		cmd = &nq->cmds[tag];
-		cmd->tag = tag;
-		cmd->error = BLK_STS_OK;
-		cmd->nq = nq;
-		cmd->bio = bio;
-		if (nq->dev->irqmode == NULL_IRQ_TIMER) {
-			hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
-				     HRTIMER_MODE_REL);
-			cmd->timer.function = null_cmd_timer_expired;
-		}
-		return cmd;
+	if (tag == NULL_REQ_TAG_NOT_AVAILABLE)
+		return NULL;
+	cmd = &nq->cmds[tag];
+	cmd->tag = tag;
+	cmd->error = BLK_STS_OK;
+	cmd->nq = nq;
+	cmd->bio = bio;
+	if (nq->dev->irqmode == NULL_IRQ_TIMER) {
+		hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
+				HRTIMER_MODE_REL);
+		cmd->timer.function = null_cmd_timer_expired;
 	}
-
-	return NULL;
+	return cmd;
 }
 
 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, struct bio *bio)
-- 
2.29.0