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scsi: scsi_debug: mq_poll support

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Add support of the mq_poll interface to scsi_debug.  This feature
requires shared host tag support in kernel and driver.

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Link: https://lore.kernel.org/r/20210215074048.19424-4-kashyap.desai@broadcom.com
Cc: dgilbert@interlog.com
Cc: linux-block@vger.kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Kashyap Desai 2021-02-15 13:10:46 +05:30 committed by Martin K. Petersen
parent 9e4bec5b2a
commit c4b57d89ba
1 changed files with 130 additions and 0 deletions
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130
drivers/scsi/scsi_debug.c
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@ -829,6 +829,7 @@ static int sdeb_zbc_max_open = DEF_ZBC_MAX_OPEN_ZONES;
static int sdeb_zbc_nr_conv = DEF_ZBC_NR_CONV_ZONES;
static int submit_queues = DEF_SUBMIT_QUEUES; /* > 1 for multi-queue (mq) */
static int poll_queues; /* iouring iopoll interface.*/
static struct sdebug_queue *sdebug_q_arr; /* ptr to array of submit queues */
static DEFINE_RWLOCK(atomic_rw);
@ -5432,6 +5433,14 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
cmnd->host_scribble = (unsigned char *)sqcp;
sd_dp = sqcp->sd_dp;
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
/* Do not complete IO from default completion path.
* Let it to be on queue.
* Completion should happen from mq_poll interface.
*/
if ((sqp - sdebug_q_arr) >= (submit_queues - poll_queues))
return 0;
if (!sd_dp) {
sd_dp = kzalloc(sizeof(*sd_dp), GFP_ATOMIC);
if (!sd_dp) {
@ -5615,6 +5624,7 @@ module_param_named(sector_size, sdebug_sector_size, int, S_IRUGO);
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(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);
@ -5677,6 +5687,7 @@ MODULE_PARM_DESC(opt_xferlen_exp, "optimal transfer length granularity exponent
MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)");
MODULE_PARM_DESC(per_host_store, "If set, next positive add_host will get new store (def=0)");
MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)");
MODULE_PARM_DESC(poll_queues, "support for iouring iopoll queues (1 to max(submit_queues - 1)");
MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])");
MODULE_PARM_DESC(random, "If set, uniformly randomize command duration between 0 and delay_in_ns");
MODULE_PARM_DESC(removable, "claim to have removable media (def=0)");
@ -7202,6 +7213,104 @@ static int resp_not_ready(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
return check_condition_result;
}
static int sdebug_map_queues(struct Scsi_Host *shost)
{
int i, qoff;
if (shost->nr_hw_queues == 1)
return 0;
for (i = 0, qoff = 0; i < HCTX_MAX_TYPES; i++) {
struct blk_mq_queue_map *map = &shost->tag_set.map[i];
map->nr_queues = 0;
if (i == HCTX_TYPE_DEFAULT)
map->nr_queues = submit_queues - poll_queues;
else if (i == HCTX_TYPE_POLL)
map->nr_queues = poll_queues;
if (!map->nr_queues) {
BUG_ON(i == HCTX_TYPE_DEFAULT);
continue;
}
map->queue_offset = qoff;
blk_mq_map_queues(map);
qoff += map->nr_queues;
}
return 0;
}
static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
{
int qc_idx;
int retiring = 0;
unsigned long iflags;
struct sdebug_queue *sqp;
struct sdebug_queued_cmd *sqcp;
struct scsi_cmnd *scp;
struct sdebug_dev_info *devip;
int num_entries = 0;
sqp = sdebug_q_arr + queue_num;
do {
spin_lock_irqsave(&sqp->qc_lock, iflags);
qc_idx = find_first_bit(sqp->in_use_bm, sdebug_max_queue);
if (unlikely((qc_idx < 0) || (qc_idx >= sdebug_max_queue)))
goto out;
sqcp = &sqp->qc_arr[qc_idx];
scp = sqcp->a_cmnd;
if (unlikely(scp == NULL)) {
pr_err("scp is NULL, queue_num=%d, qc_idx=%d from %s\n",
queue_num, qc_idx, __func__);
goto out;
}
devip = (struct sdebug_dev_info *)scp->device->hostdata;
if (likely(devip))
atomic_dec(&devip->num_in_q);
else
pr_err("devip=NULL from %s\n", __func__);
if (unlikely(atomic_read(&retired_max_queue) > 0))
retiring = 1;
sqcp->a_cmnd = NULL;
if (unlikely(!test_and_clear_bit(qc_idx, sqp->in_use_bm))) {
pr_err("Unexpected completion sqp %p queue_num=%d qc_idx=%d from %s\n",
sqp, queue_num, qc_idx, __func__);
goto out;
}
if (unlikely(retiring)) { /* user has reduced max_queue */
int k, retval;
retval = atomic_read(&retired_max_queue);
if (qc_idx >= retval) {
pr_err("index %d too large\n", retval);
goto out;
}
k = find_last_bit(sqp->in_use_bm, retval);
if ((k < sdebug_max_queue) || (k == retval))
atomic_set(&retired_max_queue, 0);
else
atomic_set(&retired_max_queue, k + 1);
}
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
scp->scsi_done(scp); /* callback to mid level */
num_entries++;
} while (1);
out:
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
return num_entries;
}
static int scsi_debug_queuecommand(struct Scsi_Host *shost,
struct scsi_cmnd *scp)
{
@ -7381,6 +7490,8 @@ static struct scsi_host_template sdebug_driver_template = {
.ioctl = scsi_debug_ioctl,
.queuecommand = scsi_debug_queuecommand,
.change_queue_depth = sdebug_change_qdepth,
.map_queues = sdebug_map_queues,
.mq_poll = sdebug_blk_mq_poll,
.eh_abort_handler = scsi_debug_abort,
.eh_device_reset_handler = scsi_debug_device_reset,
.eh_target_reset_handler = scsi_debug_target_reset,
@ -7428,6 +7539,25 @@ static int sdebug_driver_probe(struct device *dev)
if (sdebug_host_max_queue)
hpnt->host_tagset = 1;
/* poll queues are possible for nr_hw_queues > 1 */
if (hpnt->nr_hw_queues == 1 || (poll_queues < 1)) {
pr_warn("%s: trim poll_queues to 0. poll_q/nr_hw = (%d/%d)\n",
my_name, poll_queues, hpnt->nr_hw_queues);
poll_queues = 0;
}
/*
* Poll queues don't need interrupts, but we need at least one I/O queue
* left over for non-polled I/O.
* If condition not met, trim poll_queues to 1 (just for simplicity).
*/
if (poll_queues >= submit_queues) {
pr_warn("%s: trim poll_queues to 1\n", my_name);
poll_queues = 1;
}
if (poll_queues)
hpnt->nr_maps = 3;
sdbg_host->shost = hpnt;
*((struct sdebug_host_info **)hpnt->hostdata) = sdbg_host;
if ((hpnt->this_id >= 0) && (sdebug_num_tgts > hpnt->this_id))