[PATCH v3 06/11] scsi: scsi_debug: Dynamically allocate sdebug_queued_cmd

From: John Garry
Date: Mon Mar 27 2023 - 03:44:31 EST

Eventually we will drop the sdebug_queue struct as it is not really
required, so start with making the sdebug_queued_cmd dynamically allocated
for the lifetime of the scsi_cmnd in the driver.

As an interim measure, make sdebug_queued_cmd.sd_dp a pointer to struct
sdebug_defer. Also keep a value of the index allocated in
sdebug_queued_cmd.qc_arr in struct sdebug_queued_cmd.

To deal with an races in accessing the scsi cmnd allocated struct
sdebug_queued_cmd, add a spinlock for the scsi command in its priv area.
Races may be between scheduling a command for completion, aborting a
command, and the command actually completing and freeing the struct
sdebug_queued_cmd.

Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
drivers/scsi/scsi_debug.c | 427 ++++++++++++++++++++++----------------
1 file changed, 253 insertions(+), 174 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index f53f3e78aaa1..7dd2dd6cbd6c 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -250,6 +250,11 @@ static const char *sdebug_version_date = "20210520";

#define SDEB_XA_NOT_IN_USE XA_MARK_1

+static struct kmem_cache *queued_cmd_cache;
+
+#define TO_QEUEUED_CMD(scmd) ((void *)(scmd)->host_scribble)
+#define ASSIGN_QEUEUED_CMD(scmnd, qc) { (scmnd)->host_scribble = (void *) qc; }
+
/* Zone types (zbcr05 table 25) */
enum sdebug_z_type {
ZBC_ZTYPE_CNV = 0x1,
@@ -337,12 +342,8 @@ struct sdebug_defer {
struct execute_work ew;
ktime_t cmpl_ts;/* time since boot to complete this cmd */
int sqa_idx; /* index of sdebug_queue array */
- int qc_idx; /* index of sdebug_queued_cmd array within sqa_idx */
int hc_idx; /* hostwide tag index */
int issuing_cpu;
- bool init_hrt;
- bool init_wq;
- bool init_poll;
bool aborted; /* true when blk_abort_request() already called */
enum sdeb_defer_type defer_t;
};
@@ -351,12 +352,16 @@ struct sdebug_queued_cmd {
/* corresponding bit set in in_use_bm[] in owning struct sdebug_queue
* instance indicates this slot is in use.
*/
- struct sdebug_defer *sd_dp;
- struct scsi_cmnd *a_cmnd;
+ struct sdebug_defer sd_dp;
+ struct scsi_cmnd *scmd;
+};
+
+struct sdebug_scsi_cmd {
+ spinlock_t lock;
};

struct sdebug_queue {
- struct sdebug_queued_cmd qc_arr[SDEBUG_CANQUEUE];
+ struct sdebug_queued_cmd *qc_arr[SDEBUG_CANQUEUE];
unsigned long in_use_bm[SDEBUG_CANQUEUE_WORDS];
spinlock_t qc_lock;
};
@@ -508,6 +513,8 @@ static int sdebug_add_store(void);
static void sdebug_erase_store(int idx, struct sdeb_store_info *sip);
static void sdebug_erase_all_stores(bool apart_from_first);

+static void sdebug_free_queued_cmd(struct sdebug_queued_cmd *sqcp);
+
/*
* The following are overflow arrays for cdbs that "hit" the same index in
* the opcode_info_arr array. The most time sensitive (or commonly used) cdb
@@ -4919,46 +4926,48 @@ static u32 get_tag(struct scsi_cmnd *cmnd)
/* Queued (deferred) command completions converge here. */
static void sdebug_q_cmd_complete(struct sdebug_defer *sd_dp)
{
- bool aborted = sd_dp->aborted;
+ struct sdebug_queued_cmd *sqcp = container_of(sd_dp, struct sdebug_queued_cmd, sd_dp);
int qc_idx;
int retiring = 0;
- unsigned long iflags;
+ unsigned long flags, iflags;
+ struct scsi_cmnd *scp = sqcp->scmd;
+ struct sdebug_scsi_cmd *sdsc;
+ bool aborted;
struct sdebug_queue *sqp;
- struct sdebug_queued_cmd *sqcp;
- struct scsi_cmnd *scp;

- if (unlikely(aborted))
- sd_dp->aborted = false;
- qc_idx = sd_dp->qc_idx;
- sqp = sdebug_q_arr + sd_dp->sqa_idx;
+ qc_idx = sd_dp->sqa_idx;
if (sdebug_statistics) {
atomic_inc(&sdebug_completions);
if (raw_smp_processor_id() != sd_dp->issuing_cpu)
atomic_inc(&sdebug_miss_cpus);
}
+ if (!scp) {
+ pr_err("scmd=NULL\n");
+ goto out;
+ }
if (unlikely((qc_idx < 0) || (qc_idx >= SDEBUG_CANQUEUE))) {
pr_err("wild qc_idx=%d\n", qc_idx);
- return;
+ goto out;
}
+
+ sdsc = scsi_cmd_priv(scp);
+ sqp = get_queue(scp);
spin_lock_irqsave(&sqp->qc_lock, iflags);
- WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_NONE);
- sqcp = &sqp->qc_arr[qc_idx];
- scp = sqcp->a_cmnd;
- if (unlikely(scp == NULL)) {
- spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- pr_err("scp is NULL, sqa_idx=%d, qc_idx=%d, hc_idx=%d\n",
- sd_dp->sqa_idx, qc_idx, sd_dp->hc_idx);
- return;
- }
+ spin_lock_irqsave(&sdsc->lock, flags);
+ aborted = sd_dp->aborted;
+ if (unlikely(aborted))
+ sd_dp->aborted = false;
+ ASSIGN_QEUEUED_CMD(scp, NULL);

if (unlikely(atomic_read(&retired_max_queue) > 0))
retiring = 1;

- sqcp->a_cmnd = NULL;
+ sqp->qc_arr[qc_idx] = NULL;
if (unlikely(!test_and_clear_bit(qc_idx, sqp->in_use_bm))) {
+ spin_unlock_irqrestore(&sdsc->lock, flags);
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- pr_err("Unexpected completion\n");
- return;
+ pr_err("Unexpected completion qc_idx=%d\n", qc_idx);
+ goto out;
}

if (unlikely(retiring)) { /* user has reduced max_queue */
@@ -4966,9 +4975,10 @@ static void sdebug_q_cmd_complete(struct sdebug_defer *sd_dp)

retval = atomic_read(&retired_max_queue);
if (qc_idx >= retval) {
+ spin_unlock_irqrestore(&sdsc->lock, flags);
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
pr_err("index %d too large\n", retval);
- return;
+ goto out;
}
k = find_last_bit(sqp->in_use_bm, retval);
if ((k < sdebug_max_queue) || (k == retval))
@@ -4976,14 +4986,19 @@ static void sdebug_q_cmd_complete(struct sdebug_defer *sd_dp)
else
atomic_set(&retired_max_queue, k + 1);
}
+
+ spin_unlock_irqrestore(&sdsc->lock, flags);
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- if (unlikely(aborted)) {
- if (sdebug_verbose)
- pr_info("bypassing scsi_done() due to aborted cmd, kicking-off EH\n");
+
+ if (aborted) {
+ pr_info("bypassing scsi_done() due to aborted cmd, kicking-off EH\n");
blk_abort_request(scsi_cmd_to_rq(scp));
- return;
+ goto out;
}
+
scsi_done(scp); /* callback to mid level */
+out:
+ sdebug_free_queued_cmd(sqcp);
}

/* When high resolution timer goes off this function is called. */
@@ -5233,115 +5248,126 @@ static void scsi_debug_slave_destroy(struct scsi_device *sdp)
}
}

-static void stop_qc_helper(struct sdebug_defer *sd_dp,
+/* Returns true if we require the queued memory to be freed by the caller. */
+static bool stop_qc_helper(struct sdebug_defer *sd_dp,
enum sdeb_defer_type defer_t)
{
- if (!sd_dp)
- return;
- if (defer_t == SDEB_DEFER_HRT)
- hrtimer_cancel(&sd_dp->hrt);
- else if (defer_t == SDEB_DEFER_WQ)
- cancel_work_sync(&sd_dp->ew.work);
+ if (defer_t == SDEB_DEFER_HRT) {
+ int res = hrtimer_try_to_cancel(&sd_dp->hrt);
+
+ switch (res) {
+ case 0: /* Not active, it must have already run */
+ case -1: /* -1 It's executing the CB */
+ return false;
+ case 1: /* Was active, we've now cancelled */
+ default:
+ return true;
+ }
+ } else if (defer_t == SDEB_DEFER_WQ) {
+ /* Cancel if pending */
+ if (cancel_work_sync(&sd_dp->ew.work))
+ return true;
+ /* Was not pending, so it must have run */
+ return false;
+ } else if (defer_t == SDEB_DEFER_POLL) {
+ return true;
+ }
+
+ return false;
}

-/* If @cmnd found deletes its timer or work queue and returns true; else
- returns false */
-static bool stop_queued_cmnd(struct scsi_cmnd *cmnd)
+
+static bool scsi_debug_stop_cmnd(struct scsi_cmnd *cmnd, int *sqa_idx)
{
- unsigned long iflags;
- int j, k, qmax, r_qmax;
enum sdeb_defer_type l_defer_t;
- struct sdebug_queue *sqp;
struct sdebug_queued_cmd *sqcp;
struct sdebug_defer *sd_dp;
+ struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmnd);

- for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp) {
+ lockdep_assert_held(&sdsc->lock);
+
+ sqcp = TO_QEUEUED_CMD(cmnd);
+ if (!sqcp)
+ return false;
+ sd_dp = &sqcp->sd_dp;
+ if (sqa_idx)
+ *sqa_idx = sd_dp->sqa_idx;
+ l_defer_t = READ_ONCE(sd_dp->defer_t);
+ ASSIGN_QEUEUED_CMD(cmnd, NULL);
+
+ if (stop_qc_helper(sd_dp, l_defer_t))
+ sdebug_free_queued_cmd(sqcp);
+
+ return true;
+}
+
+/*
+ * Called from scsi_debug_abort() only, which is for timed-out cmd.
+ */
+static bool scsi_debug_abort_cmnd(struct scsi_cmnd *cmnd)
+{
+ struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmnd);
+ struct sdebug_queue *sqp = get_queue(cmnd);
+ unsigned long flags, iflags;
+ int k = -1;
+ bool res;
+
+ spin_lock_irqsave(&sdsc->lock, flags);
+ res = scsi_debug_stop_cmnd(cmnd, &k);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
+
+ if (k >= 0) {
spin_lock_irqsave(&sqp->qc_lock, iflags);
- qmax = sdebug_max_queue;
- r_qmax = atomic_read(&retired_max_queue);
- if (r_qmax > qmax)
- qmax = r_qmax;
- for (k = 0; k < qmax; ++k) {
- if (test_bit(k, sqp->in_use_bm)) {
- sqcp = &sqp->qc_arr[k];
- if (cmnd != sqcp->a_cmnd)
- continue;
- /* found */
- sqcp->a_cmnd = NULL;
- sd_dp = sqcp->sd_dp;
- if (sd_dp) {
- l_defer_t = READ_ONCE(sd_dp->defer_t);
- WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_NONE);
- } else
- l_defer_t = SDEB_DEFER_NONE;
- spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- stop_qc_helper(sd_dp, l_defer_t);
- clear_bit(k, sqp->in_use_bm);
- return true;
- }
- }
+ clear_bit(k, sqp->in_use_bm);
+ sqp->qc_arr[k] = NULL;
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
}
- return false;
+
+ return res;
}

/* Deletes (stops) timers or work queues of all queued commands */
static void stop_all_queued(void)
{
- unsigned long iflags;
+ unsigned long iflags, flags;
int j, k;
- enum sdeb_defer_type l_defer_t;
struct sdebug_queue *sqp;
- struct sdebug_queued_cmd *sqcp;
- struct sdebug_defer *sd_dp;

for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp) {
spin_lock_irqsave(&sqp->qc_lock, iflags);
for (k = 0; k < SDEBUG_CANQUEUE; ++k) {
if (test_bit(k, sqp->in_use_bm)) {
- sqcp = &sqp->qc_arr[k];
- if (sqcp->a_cmnd == NULL)
+ struct sdebug_queued_cmd *sqcp = sqp->qc_arr[k];
+ struct sdebug_scsi_cmd *sdsc;
+ struct scsi_cmnd *scmd;
+
+ if (!sqcp)
continue;
- sqcp->a_cmnd = NULL;
- sd_dp = sqcp->sd_dp;
- if (sd_dp) {
- l_defer_t = READ_ONCE(sd_dp->defer_t);
- WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_NONE);
- } else
- l_defer_t = SDEB_DEFER_NONE;
- spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- stop_qc_helper(sd_dp, l_defer_t);
+ scmd = sqcp->scmd;
+ if (!scmd)
+ continue;
+ sdsc = scsi_cmd_priv(scmd);
+ spin_lock_irqsave(&sdsc->lock, flags);
+ if (TO_QEUEUED_CMD(scmd) != sqcp) {
+ spin_unlock_irqrestore(&sdsc->lock, flags);
+ continue;
+ }
+ scsi_debug_stop_cmnd(scmd, NULL);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
+ sqp->qc_arr[k] = NULL;
clear_bit(k, sqp->in_use_bm);
- spin_lock_irqsave(&sqp->qc_lock, iflags);
}
}
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
}
}

-/* Free queued command memory on heap */
-static void free_all_queued(void)
-{
- int j, k;
- struct sdebug_queue *sqp;
- struct sdebug_queued_cmd *sqcp;
-
- for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp) {
- for (k = 0; k < SDEBUG_CANQUEUE; ++k) {
- sqcp = &sqp->qc_arr[k];
- kfree(sqcp->sd_dp);
- sqcp->sd_dp = NULL;
- }
- }
-}
-
static int scsi_debug_abort(struct scsi_cmnd *SCpnt)
{
- bool ok;
+ bool ok = scsi_debug_abort_cmnd(SCpnt);

++num_aborts;

- ok = stop_queued_cmnd(SCpnt);
if (SDEBUG_OPT_ALL_NOISE & sdebug_opts)
sdev_printk(KERN_INFO, SCpnt->device,
"%s: command%s found\n", __func__,
@@ -5543,6 +5569,34 @@ static bool inject_on_this_cmd(void)

#define INCLUSIVE_TIMING_MAX_NS 1000000 /* 1 millisecond */

+
+void sdebug_free_queued_cmd(struct sdebug_queued_cmd *sqcp)
+{
+ if (sqcp)
+ kmem_cache_free(queued_cmd_cache, sqcp);
+}
+
+static struct sdebug_queued_cmd *sdebug_alloc_queued_cmd(struct scsi_cmnd *scmd)
+{
+ struct sdebug_queued_cmd *sqcp;
+ struct sdebug_defer *sd_dp;
+
+ sqcp = kmem_cache_zalloc(queued_cmd_cache, GFP_ATOMIC);
+ if (!sqcp)
+ return NULL;
+
+ sd_dp = &sqcp->sd_dp;
+
+ hrtimer_init(&sd_dp->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
+ sd_dp->hrt.function = sdebug_q_cmd_hrt_complete;
+ INIT_WORK(&sd_dp->ew.work, sdebug_q_cmd_wq_complete);
+
+ sqcp->scmd = scmd;
+ sd_dp->sqa_idx = -1;
+
+ return sqcp;
+}
+
/* Complete the processing of the thread that queued a SCSI command to this
* driver. It either completes the command by calling cmnd_done() or
* schedules a hr timer or work queue then returns 0. Returns
@@ -5554,15 +5608,16 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
struct sdebug_dev_info *),
int delta_jiff, int ndelay)
{
- bool new_sd_dp;
- bool polled = scsi_cmd_to_rq(cmnd)->cmd_flags & REQ_POLLED;
- int k;
- unsigned long iflags;
+ struct request *rq = scsi_cmd_to_rq(cmnd);
+ bool polled = rq->cmd_flags & REQ_POLLED;
+ struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmnd);
+ unsigned long iflags, flags;
u64 ns_from_boot = 0;
struct sdebug_queue *sqp;
struct sdebug_queued_cmd *sqcp;
struct scsi_device *sdp;
struct sdebug_defer *sd_dp;
+ int k;

if (unlikely(devip == NULL)) {
if (scsi_result == 0)
@@ -5606,22 +5661,17 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
goto respond_in_thread;
}
set_bit(k, sqp->in_use_bm);
- sqcp = &sqp->qc_arr[k];
- sqcp->a_cmnd = cmnd;
- cmnd->host_scribble = (unsigned char *)sqcp;
- sd_dp = sqcp->sd_dp;
- spin_unlock_irqrestore(&sqp->qc_lock, iflags);

- if (!sd_dp) {
- sd_dp = kzalloc(sizeof(*sd_dp), GFP_ATOMIC);
- if (!sd_dp) {
- clear_bit(k, sqp->in_use_bm);
- return SCSI_MLQUEUE_HOST_BUSY;
- }
- new_sd_dp = true;
- } else {
- new_sd_dp = false;
+ sqcp = sdebug_alloc_queued_cmd(cmnd);
+ if (!sqcp) {
+ clear_bit(k, sqp->in_use_bm);
+ spin_unlock_irqrestore(&sqp->qc_lock, iflags);
+ return SCSI_MLQUEUE_HOST_BUSY;
}
+ sd_dp = &sqcp->sd_dp;
+ sd_dp->sqa_idx = k;
+ sqp->qc_arr[k] = sqcp;
+ spin_unlock_irqrestore(&sqp->qc_lock, iflags);

/* Set the hostwide tag */
if (sdebug_host_max_queue)
@@ -5673,12 +5723,11 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,

if (kt <= d) { /* elapsed duration >= kt */
spin_lock_irqsave(&sqp->qc_lock, iflags);
- sqcp->a_cmnd = NULL;
+ sqp->qc_arr[k] = NULL;
clear_bit(k, sqp->in_use_bm);
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- if (new_sd_dp)
- kfree(sd_dp);
/* call scsi_done() from this thread */
+ sdebug_free_queued_cmd(sqcp);
scsi_done(cmnd);
return 0;
}
@@ -5686,33 +5735,28 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
kt -= d;
}
}
+ if (sdebug_statistics)
+ sd_dp->issuing_cpu = raw_smp_processor_id();
if (polled) {
+ spin_lock_irqsave(&sdsc->lock, flags);
sd_dp->cmpl_ts = ktime_add(ns_to_ktime(ns_from_boot), kt);
- spin_lock_irqsave(&sqp->qc_lock, iflags);
- if (!sd_dp->init_poll) {
- sd_dp->init_poll = true;
- sqcp->sd_dp = sd_dp;
- sd_dp->sqa_idx = sqp - sdebug_q_arr;
- sd_dp->qc_idx = k;
- }
+ ASSIGN_QEUEUED_CMD(cmnd, sqcp);
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_POLL);
- spin_unlock_irqrestore(&sqp->qc_lock, iflags);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
} else {
- if (!sd_dp->init_hrt) {
- sd_dp->init_hrt = true;
- sqcp->sd_dp = sd_dp;
- hrtimer_init(&sd_dp->hrt, CLOCK_MONOTONIC,
- HRTIMER_MODE_REL_PINNED);
- sd_dp->hrt.function = sdebug_q_cmd_hrt_complete;
- sd_dp->sqa_idx = sqp - sdebug_q_arr;
- sd_dp->qc_idx = k;
- }
- WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_HRT);
/* schedule the invocation of scsi_done() for a later time */
+ spin_lock_irqsave(&sdsc->lock, flags);
+ ASSIGN_QEUEUED_CMD(cmnd, sqcp);
+ WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_HRT);
hrtimer_start(&sd_dp->hrt, kt, HRTIMER_MODE_REL_PINNED);
+ /*
+ * The completion handler will try to grab sqcp->lock,
+ * so there is no chance that the completion handler
+ * will call scsi_done() until we release the lock
+ * here (so ok to keep referencing sdsc).
+ */
+ spin_unlock_irqrestore(&sdsc->lock, flags);
}
- if (sdebug_statistics)
- sd_dp->issuing_cpu = raw_smp_processor_id();
} else { /* jdelay < 0, use work queue */
if (unlikely((sdebug_opts & SDEBUG_OPT_CMD_ABORT) &&
atomic_read(&sdeb_inject_pending))) {
@@ -5722,30 +5766,21 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
blk_mq_unique_tag_to_tag(get_tag(cmnd)));
}

+ if (sdebug_statistics)
+ sd_dp->issuing_cpu = raw_smp_processor_id();
if (polled) {
+ spin_lock_irqsave(&sdsc->lock, flags);
+ ASSIGN_QEUEUED_CMD(cmnd, sqcp);
sd_dp->cmpl_ts = ns_to_ktime(ns_from_boot);
- spin_lock_irqsave(&sqp->qc_lock, iflags);
- if (!sd_dp->init_poll) {
- sd_dp->init_poll = true;
- sqcp->sd_dp = sd_dp;
- sd_dp->sqa_idx = sqp - sdebug_q_arr;
- sd_dp->qc_idx = k;
- }
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_POLL);
- spin_unlock_irqrestore(&sqp->qc_lock, iflags);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
} else {
- if (!sd_dp->init_wq) {
- sd_dp->init_wq = true;
- sqcp->sd_dp = sd_dp;
- sd_dp->sqa_idx = sqp - sdebug_q_arr;
- sd_dp->qc_idx = k;
- INIT_WORK(&sd_dp->ew.work, sdebug_q_cmd_wq_complete);
- }
+ spin_lock_irqsave(&sdsc->lock, flags);
+ ASSIGN_QEUEUED_CMD(cmnd, sqcp);
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_WQ);
schedule_work(&sd_dp->ew.work);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
}
- if (sdebug_statistics)
- sd_dp->issuing_cpu = raw_smp_processor_id();
}

return 0;
@@ -7066,6 +7101,10 @@ static int __init scsi_debug_init(void)
hosts_to_add = sdebug_add_host;
sdebug_add_host = 0;

+ queued_cmd_cache = KMEM_CACHE(sdebug_queued_cmd, SLAB_HWCACHE_ALIGN);
+ if (!queued_cmd_cache)
+ goto driver_unreg;
+
for (k = 0; k < hosts_to_add; k++) {
if (want_store && k == 0) {
ret = sdebug_add_host_helper(idx);
@@ -7088,6 +7127,8 @@ static int __init scsi_debug_init(void)

return 0;

+driver_unreg:
+ driver_unregister(&sdebug_driverfs_driver);
bus_unreg:
bus_unregister(&pseudo_lld_bus);
dev_unreg:
@@ -7103,10 +7144,9 @@ static void __exit scsi_debug_exit(void)
{
int k = sdebug_num_hosts;

- stop_all_queued();
for (; k; k--)
sdebug_do_remove_host(true);
- free_all_queued();
+ kmem_cache_destroy(queued_cmd_cache);
driver_unregister(&sdebug_driverfs_driver);
bus_unregister(&pseudo_lld_bus);
root_device_unregister(pseudo_primary);
@@ -7493,6 +7533,8 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
goto unlock;

for (first = true; first || qc_idx + 1 < sdebug_max_queue; ) {
+ unsigned long flags;
+ struct sdebug_scsi_cmd *sdsc;
if (first) {
first = false;
if (!test_bit(qc_idx, sqp->in_use_bm))
@@ -7503,37 +7545,60 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
if (qc_idx >= sdebug_max_queue)
break;

- sqcp = &sqp->qc_arr[qc_idx];
- sd_dp = sqcp->sd_dp;
- if (unlikely(!sd_dp))
- continue;
- scp = sqcp->a_cmnd;
+ sqcp = sqp->qc_arr[qc_idx];
+ if (!sqcp) {
+ pr_err("sqcp is NULL, queue_num=%d, qc_idx=%u from %s\n",
+ queue_num, qc_idx, __func__);
+ break;
+ }
+ sd_dp = &sqcp->sd_dp;
+
+ scp = sqcp->scmd;
if (unlikely(scp == NULL)) {
pr_err("scp is NULL, queue_num=%d, qc_idx=%u from %s\n",
queue_num, qc_idx, __func__);
break;
}
+ sdsc = scsi_cmd_priv(scp);
+ spin_lock_irqsave(&sdsc->lock, flags);
if (READ_ONCE(sd_dp->defer_t) == SDEB_DEFER_POLL) {
- if (kt_from_boot < sd_dp->cmpl_ts)
+ struct sdebug_queued_cmd *_sqcp = TO_QEUEUED_CMD(scp);
+
+ if (_sqcp != sqcp) {
+ pr_err("inconsistent queued cmd tag=%#x\n",
+ blk_mq_unique_tag(scsi_cmd_to_rq(scp)));
+ spin_unlock_irqrestore(&sdsc->lock, flags);
continue;
+ }
+
+ if (kt_from_boot < sd_dp->cmpl_ts) {
+ spin_unlock_irqrestore(&sdsc->lock, flags);
+ continue;
+ }

- } else /* ignoring non REQ_POLLED requests */
+ } else /* ignoring non REQ_POLLED requests */ {
+ spin_unlock_irqrestore(&sdsc->lock, flags);
continue;
+ }
if (unlikely(atomic_read(&retired_max_queue) > 0))
retiring = true;

- sqcp->a_cmnd = NULL;
if (unlikely(!test_and_clear_bit(qc_idx, sqp->in_use_bm))) {
+ spin_unlock_irqrestore(&sdsc->lock, flags);
pr_err("Unexpected completion sqp %p queue_num=%d qc_idx=%u from %s\n",
sqp, queue_num, qc_idx, __func__);
+ sdebug_free_queued_cmd(sqcp);
break;
}
+ sqp->qc_arr[qc_idx] = NULL;
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);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
+ sdebug_free_queued_cmd(sqcp);
break;
}
k = find_last_bit(sqp->in_use_bm, retval);
@@ -7542,7 +7607,7 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
else
atomic_set(&retired_max_queue, k + 1);
}
- WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_NONE);
+ spin_unlock_irqrestore(&sdsc->lock, flags);
spin_unlock_irqrestore(&sqp->qc_lock, iflags);

if (sdebug_statistics) {
@@ -7551,6 +7616,8 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
atomic_inc(&sdebug_miss_cpus);
}

+ sdebug_free_queued_cmd(sqcp);
+
scsi_done(scp); /* callback to mid level */
num_entries++;
spin_lock_irqsave(&sqp->qc_lock, iflags);
@@ -7733,6 +7800,16 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
return schedule_resp(scp, NULL, DID_NO_CONNECT << 16, NULL, 0, 0);
}

+static int sdebug_init_cmd_priv(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
+{
+ struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmd);
+
+ spin_lock_init(&sdsc->lock);
+
+ return 0;
+}
+
+
static struct scsi_host_template sdebug_driver_template = {
.show_info = scsi_debug_show_info,
.write_info = scsi_debug_write_info,
@@ -7760,6 +7837,8 @@ static struct scsi_host_template sdebug_driver_template = {
.max_segment_size = -1U,
.module = THIS_MODULE,
.track_queue_depth = 1,
+ .cmd_size = sizeof(struct sdebug_scsi_cmd),
+ .init_cmd_priv = sdebug_init_cmd_priv,
};

static int sdebug_driver_probe(struct device *dev)
--
2.35.3