[PATCH RFC v2 02/24] scsi: allocate separate queue for reserved commands

John Garry
2020-03-10T16:31:54Z

From: Hannes Reinecke <hare@suse.com>

Allocate a separate 'reserved_cmd_q' for sending reserved commands.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/scsi_lib.c | 17 ++++++++++++++++-
include/scsi/scsi_host.h | 1 +
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 2967325df7a0..e809b0e30a11 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1881,6 +1881,7 @@ struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
int scsi_mq_setup_tags(struct Scsi_Host *shost)
{
unsigned int cmd_size, sgl_size;
+ int ret;

sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
scsi_mq_inline_sgl_size(shost));
@@ -1904,11 +1905,25 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
shost->tag_set.driver_data = shost;

- return blk_mq_alloc_tag_set(&shost->tag_set);
+ ret = blk_mq_alloc_tag_set(&shost->tag_set);
+ if (ret)
+ return ret;
+
+ if (shost->nr_reserved_cmds) {
+ shost->reserved_cmd_q = blk_mq_init_queue(&shost->tag_set);
+ if (IS_ERR(shost->reserved_cmd_q)) {
+ blk_mq_free_tag_set(&shost->tag_set);
+ ret = PTR_ERR(shost->reserved_cmd_q);
+ shost->reserved_cmd_q = NULL;
+ }
+ }
+ return ret;
}

void scsi_mq_destroy_tags(struct Scsi_Host *shost)
{
+ if (shost->reserved_cmd_q)
+ blk_cleanup_queue(shost->reserved_cmd_q);
blk_mq_free_tag_set(&shost->tag_set);
}

diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 3f860c8ad623..2258a4f7b4d8 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -604,6 +604,7 @@ struct Scsi_Host {
* Number of reserved commands, if any.
*/
unsigned nr_reserved_cmds;
+ struct request_queue *reserved_cmd_q;

unsigned active_mode:2;
unsigned unchecked_isa_dma:1;
--
2.17.1