Commit b125bb99 authored by Bart Van Assche's avatar Bart Van Assche Committed by Martin K. Petersen
Browse files

scsi: core: Support setting BLK_MQ_F_BLOCKING 

Prepare for adding code in ufshcd_queuecommand() that may sleep. This patch
is similar to a patch posted last year by Mike Christie. See also
https://lore.kernel.org/all/20220308003957.123312-2-michael.christie@oracle.com/



Cc: Mike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230529202640.11883-3-bvanassche@acm.org


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent c854bcdf

drivers/scsi/hosts.c

+1 −0
Original line number Diff line number Diff line
@@ -441,6 +441,7 @@ struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *sht, int priv 
	shost->cmd_per_lun = sht->cmd_per_lun;

	shost->no_write_same = sht->no_write_same;

	shost->host_tagset = sht->host_tagset;

	shost->queuecommand_may_block = sht->queuecommand_may_block;



	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)

		shost->eh_deadline = -1;

drivers/scsi/scsi_lib.c

+4 −7
Original line number Diff line number Diff line
@@ -1982,6 +1982,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) 
	tag_set->flags = BLK_MQ_F_SHOULD_MERGE;

	tag_set->flags |=

		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);

	if (shost->queuecommand_may_block)

		tag_set->flags |= BLK_MQ_F_BLOCKING;

	tag_set->driver_data = shost;

	if (shost->host_tagset)

		tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
@@ -2968,13 +2970,8 @@ scsi_host_block(struct Scsi_Host *shost) 
		}

	}



	/*

	 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so

	 * calling synchronize_rcu() once is enough.

	 */

	WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);



	synchronize_rcu();

	/* Wait for ongoing scsi_queue_rq() calls to finish. */

	blk_mq_wait_quiesce_done(&shost->tag_set);



	return 0;

}

include/scsi/scsi_host.h

+6 −0
Original line number Diff line number Diff line
@@ -458,6 +458,9 @@ struct scsi_host_template { 
	/* True if the host uses host-wide tagspace */

	unsigned host_tagset:1;



	/* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */

	unsigned queuecommand_may_block:1;



	/*

	 * Countdown for host blocking with no commands outstanding.

	 */
@@ -653,6 +656,9 @@ struct Scsi_Host { 
	/* True if the host uses host-wide tagspace */

	unsigned host_tagset:1;



	/* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */

	unsigned queuecommand_may_block:1;



	/* Host responded with short (<36 bytes) INQUIRY result */

	unsigned short_inquiry:1;