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[v14,12/19] scsi: scsi_debug: Add the preserves_write_order module parameter

Message ID 20231023215638.3405959-13-bvanassche@acm.org
State New
Headers show
Series Improve write performance for zoned UFS devices​ | expand

Commit Message

Bart Van Assche Oct. 23, 2023, 9:54 p.m. UTC 
Zone write locking is not used for zoned devices if the block driver
reports that it preserves the order of write commands. Make it easier to
test not using zone write locking by adding support for setting the
driver_preserves_write_order flag.

Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_debug.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Bart Van Assche Oct. 24, 2023, 5:25 p.m. UTC | #1 
On 10/23/23 17:13, Damien Le Moal wrote:
> On 10/24/23 06:54, Bart Van Assche wrote:
>>   static int scsi_debug_slave_alloc(struct scsi_device *sdp)
>>   {
>> +	struct request_queue *q = sdp->request_queue;
>> +
>>   	if (sdebug_verbose)
>>   		pr_info("slave_alloc <%u %u %u %llu>\n",
>>   		       sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
>> +	if (sdeb_preserves_write_order)
>> +		q->limits.driver_preserves_write_order = true;
> 
> Nit: this could simply be:
> 
> 	q->limits.driver_preserves_write_order = sdeb_preserves_write_order;
> 
>>   	return 0;
>>   }

I will make this change.

> Otherwise, looks OK to me.
> 
> Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

Thanks for the review!

Bart.
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Patch

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 9c0af50501f9..1ea4925d2c2f 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -832,6 +832,7 @@  static int dix_reads;
 static int dif_errors;
 
 /* ZBC global data */
+static bool sdeb_preserves_write_order;
 static bool sdeb_zbc_in_use;	/* true for host-aware and host-managed disks */
 static int sdeb_zbc_zone_cap_mb;
 static int sdeb_zbc_zone_size_mb;
@@ -5138,9 +5139,13 @@  static struct sdebug_dev_info *find_build_dev_info(struct scsi_device *sdev)
 
 static int scsi_debug_slave_alloc(struct scsi_device *sdp)
 {
+	struct request_queue *q = sdp->request_queue;
+
 	if (sdebug_verbose)
 		pr_info("slave_alloc <%u %u %u %llu>\n",
 		       sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
+	if (sdeb_preserves_write_order)
+		q->limits.driver_preserves_write_order = true;
 	return 0;
 }
 
@@ -5755,6 +5760,8 @@  module_param_named(statistics, sdebug_statistics, bool, S_IRUGO | S_IWUSR);
 module_param_named(strict, sdebug_strict, bool, S_IRUGO | S_IWUSR);
 module_param_named(submit_queues, submit_queues, int, S_IRUGO);
 module_param_named(poll_queues, poll_queues, int, S_IRUGO);
+module_param_named(preserves_write_order, sdeb_preserves_write_order, bool,
+		   S_IRUGO);
 module_param_named(tur_ms_to_ready, sdeb_tur_ms_to_ready, int, S_IRUGO);
 module_param_named(unmap_alignment, sdebug_unmap_alignment, int, S_IRUGO);
 module_param_named(unmap_granularity, sdebug_unmap_granularity, int, S_IRUGO);
@@ -5812,6 +5819,8 @@  MODULE_PARM_DESC(ndelay, "response delay in nanoseconds (def=0 -> ignore)");
 MODULE_PARM_DESC(no_lun_0, "no LU number 0 (def=0 -> have lun 0)");
 MODULE_PARM_DESC(no_rwlock, "don't protect user data reads+writes (def=0)");
 MODULE_PARM_DESC(no_uld, "stop ULD (e.g. sd driver) attaching (def=0))");
+MODULE_PARM_DESC(preserves_write_order,
+		 "Whether or not to inform the block layer that this driver preserves the order of WRITE commands (def=0)");
 MODULE_PARM_DESC(num_parts, "number of partitions(def=0)");
 MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)");
 MODULE_PARM_DESC(opt_blks, "optimal transfer length in blocks (def=1024)");