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
 216.228.117.161 as permitted sender) receiver=protection.outlook.com;
 client-ip=216.228.117.161; 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 V2 6/7] null_blk: add param to set max disacrd sectors
Date:   Wed, 5 Oct 2022 20:18:28 -0700
Message-ID: <20221006031829.37741-7-kch@nvidia.com>
In-Reply-To: <20221006031829.37741-1-kch@nvidia.com>
References: <20221006031829.37741-1-kch@nvidia.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Oct 2022 03:19:58.6889
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 3e4c1c3a-cb2c-46ff-2477-08daa749a634
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com]
X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT092.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB6609
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

Instead of hardcoding value for the maximum discard sector to
UINT_MAX >> 9, allow user to set the value with newly added module
parameter max_discard_sectors.

To retain the backward compatibility make set default value to
UINT_MAX >> 9.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
---
 drivers/block/null_blk/main.c     | 10 +++++++++-
 drivers/block/null_blk/null_blk.h |  1 +
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 96b8aca5abda..2f787807cf63 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -216,6 +216,10 @@ static bool g_discard;
 module_param_named(discard, g_discard, bool, 0444);
 MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false");
 
+static unsigned int g_max_discard_sectors = UINT_MAX >> 9;
+module_param_named(max_discard_sectors, g_max_discard_sectors, uint, 0444);
+MODULE_PARM_DESC(max_discard_sectors, "Maximum size of a REQ_OP_DISCARD command (in 512B sectors).");
+
 static bool g_write_zeroes;
 module_param_named(write_zeroes, g_write_zeroes, bool, 0444);
 MODULE_PARM_DESC(write_zeroes, "Support write-zeores operations. Default: false");
@@ -420,6 +424,7 @@ NULLB_DEVICE_ATTR(home_node, uint, NULL);
 NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
 NULLB_DEVICE_ATTR(blocksize, uint, NULL);
 NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
+NULLB_DEVICE_ATTR(max_discard_sectors, uint, NULL);
 NULLB_DEVICE_ATTR(irqmode, uint, NULL);
 NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
 NULLB_DEVICE_ATTR(index, uint, NULL);
@@ -544,6 +549,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
 	&nullb_device_attr_queue_mode,
 	&nullb_device_attr_blocksize,
 	&nullb_device_attr_max_sectors,
+	&nullb_device_attr_max_discard_sectors,
 	&nullb_device_attr_irqmode,
 	&nullb_device_attr_hw_queue_depth,
 	&nullb_device_attr_index,
@@ -686,6 +692,7 @@ static struct nullb_device *null_alloc_dev(void)
 	dev->queue_mode = g_queue_mode;
 	dev->blocksize = g_bs;
 	dev->max_sectors = g_max_sectors;
+	dev->max_discard_sectors = g_max_discard_sectors;
 	dev->irqmode = g_irqmode;
 	dev->hw_queue_depth = g_hw_queue_depth;
 	dev->blocking = g_blocking;
@@ -1850,7 +1857,8 @@ static void null_config_discard(struct nullb *nullb)
 	}
 
 	nullb->q->limits.discard_granularity = nullb->dev->blocksize;
-	blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
+	blk_queue_max_discard_sectors(nullb->q,
+				      nullb->dev->max_discard_sectors);
 }
 
 static void null_config_write_zeroes(struct nullb *nullb)
diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
index 2c0c9c29158f..09940211326d 100644
--- a/drivers/block/null_blk/null_blk.h
+++ b/drivers/block/null_blk/null_blk.h
@@ -102,6 +102,7 @@ struct nullb_device {
 	unsigned int queue_mode; /* block interface */
 	unsigned int blocksize; /* block size */
 	unsigned int max_sectors; /* Max sectors per command */
+	unsigned int max_discard_sectors; /* Max discard sectors per command */
 	unsigned int irqmode; /* IRQ completion handler */
 	unsigned int hw_queue_depth; /* queue depth */
 	unsigned int index; /* index of the disk, only valid with a disk */
-- 
2.29.0