[PATCH v8 18/18] smartpqi: enable host tagset

John Garry
2020-08-19T15:27:12Z

From: Hannes Reinecke <hare@suse.de>

Enable host tagset for smartpqi; with this we can use the request
tag to look command from the pool avoiding the list iteration in
the hot path.

Signed-off-by: Hannes Reinecke <hare@suse.de>
[jpg: Mod ctrl_info->next_io_request_slot calc]
Signed-off-by: John Garry <john.garry@huawei.com>
---
drivers/scsi/smartpqi/smartpqi_init.c | 45 ++++++++++++++++++---------
1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index bd38c8cea56e..870ed1400a9e 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -575,22 +575,33 @@ static inline void pqi_reinit_io_request(struct pqi_io_request *io_request)
}

static struct pqi_io_request *pqi_alloc_io_request(
- struct pqi_ctrl_info *ctrl_info)
+ struct pqi_ctrl_info *ctrl_info, struct scsi_cmnd *scmd)
{
struct pqi_io_request *io_request;
- u16 i = ctrl_info->next_io_request_slot; /* benignly racy */
+ unsigned int limit = PQI_RESERVED_IO_SLOTS;
+ u16 i;

- while (1) {
+ if (scmd) {
+ u32 blk_tag = blk_mq_unique_tag(scmd->request);
+
+ i = blk_mq_unique_tag_to_tag(blk_tag) + limit;
io_request = &ctrl_info->io_request_pool[i];
- if (atomic_inc_return(&io_request->refcount) == 1)
- break;
- atomic_dec(&io_request->refcount);
- i = (i + 1) % ctrl_info->max_io_slots;
+ if (WARN_ON(atomic_inc_return(&io_request->refcount) > 1)) {
+ atomic_dec(&io_request->refcount);
+ return NULL;
+ }
+ } else {
+ i = ctrl_info->next_io_request_slot; /* benignly racy */
+ while (1) {
+ io_request = &ctrl_info->io_request_pool[i];
+ if (atomic_inc_return(&io_request->refcount) == 1)
+ break;
+ atomic_dec(&io_request->refcount);
+ i = (i + 1) % limit;
+ }
+ ctrl_info->next_io_request_slot = (i + 1) % limit;
}

- /* benignly racy */
- ctrl_info->next_io_request_slot = (i + 1) % ctrl_info->max_io_slots;
-
pqi_reinit_io_request(io_request);

return io_request;
@@ -4075,7 +4086,7 @@ static int pqi_submit_raid_request_synchronous(struct pqi_ctrl_info *ctrl_info,

atomic_inc(&ctrl_info->sync_cmds_outstanding);

- io_request = pqi_alloc_io_request(ctrl_info);
+ io_request = pqi_alloc_io_request(ctrl_info, NULL);

put_unaligned_le16(io_request->index,
&(((struct pqi_raid_path_request *)request)->request_id));
@@ -5032,7 +5043,9 @@ static inline int pqi_raid_submit_scsi_cmd(struct pqi_ctrl_info *ctrl_info,
{
struct pqi_io_request *io_request;

- io_request = pqi_alloc_io_request(ctrl_info);
+ io_request = pqi_alloc_io_request(ctrl_info, scmd);
+ if (!io_request)
+ return SCSI_MLQUEUE_HOST_BUSY;

return pqi_raid_submit_scsi_cmd_with_io_request(ctrl_info, io_request,
device, scmd, queue_group);
@@ -5230,7 +5243,10 @@ static int pqi_aio_submit_io(struct pqi_ctrl_info *ctrl_info,
struct pqi_io_request *io_request;
struct pqi_aio_path_request *request;

- io_request = pqi_alloc_io_request(ctrl_info);
+ io_request = pqi_alloc_io_request(ctrl_info, scmd);
+ if (!io_request)
+ return SCSI_MLQUEUE_HOST_BUSY;
+
io_request->io_complete_callback = pqi_aio_io_complete;
io_request->scmd = scmd;
io_request->raid_bypass = raid_bypass;
@@ -5657,7 +5673,7 @@ static int pqi_lun_reset(struct pqi_ctrl_info *ctrl_info,
DECLARE_COMPLETION_ONSTACK(wait);
struct pqi_task_management_request *request;

- io_request = pqi_alloc_io_request(ctrl_info);
+ io_request = pqi_alloc_io_request(ctrl_info, NULL);
io_request->io_complete_callback = pqi_lun_reset_complete;
io_request->context = &wait;

@@ -6504,6 +6520,7 @@ static struct scsi_host_template pqi_driver_template = {
.map_queues = pqi_map_queues,
.sdev_attrs = pqi_sdev_attrs,
.shost_attrs = pqi_shost_attrs,
+ .host_tagset = 1,
};

static int pqi_register_scsi(struct pqi_ctrl_info *ctrl_info)
--
2.26.2