Simplify command handling by moving struct sdebug_defer into the
private SCSI command data instead of allocating it separately. The only
functional change is that aborting a SCSI command now fails and is
retried at a later time if the completion handler can't be cancelled.
See also commit 1107c7b24ee3 ("scsi: scsi_debug: Dynamically allocate
sdebug_queued_cmd"; v6.4).
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: John Garry <john.g.garry@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/scsi_debug.c | 140 +++++++-------------------------------
1 file changed, 26 insertions(+), 114 deletions(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 7a0b7402b715..1597156cb573 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -253,11 +253,6 @@ 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_QUEUED_CMD(scmd) ((void *)(scmd)->host_scribble)
-#define ASSIGN_QUEUED_CMD(scmnd, qc) { (scmnd)->host_scribble = (void *) qc; }
-
/* Zone types (zbcr05 table 25) */
enum sdebug_z_type {
ZBC_ZTYPE_CNV = 0x1,
@@ -398,16 +393,9 @@ struct sdebug_defer {
enum sdeb_defer_type defer_t;
};
-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 *scmd;
-};
-
struct sdebug_scsi_cmd {
spinlock_t lock;
+ struct sdebug_defer sd_dp;
};
static atomic_t sdebug_cmnd_count; /* number of incoming commands */
@@ -559,8 +547,6 @@ 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
@@ -5332,10 +5318,9 @@ 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)
{
- struct sdebug_queued_cmd *sqcp = container_of(sd_dp, struct sdebug_queued_cmd, sd_dp);
+ struct sdebug_scsi_cmd *sdsc = container_of(sd_dp, typeof(*sdsc), sd_dp);
+ struct scsi_cmnd *scp = (struct scsi_cmnd *)sdsc - 1;
unsigned long flags;
- struct scsi_cmnd *scp = sqcp->scmd;
- struct sdebug_scsi_cmd *sdsc;
bool aborted;
if (sdebug_statistics) {
@@ -5346,7 +5331,7 @@ static void sdebug_q_cmd_complete(struct sdebug_defer *sd_dp)
if (!scp) {
pr_err("scmd=NULL\n");
- goto out;
+ return;
}
sdsc = scsi_cmd_priv(scp);
@@ -5354,19 +5339,16 @@ static void sdebug_q_cmd_complete(struct sdebug_defer *sd_dp)
aborted = sd_dp->aborted;
if (unlikely(aborted))
sd_dp->aborted = false;
- ASSIGN_QUEUED_CMD(scp, NULL);
spin_unlock_irqrestore(&sdsc->lock, flags);
if (aborted) {
pr_info("bypassing scsi_done() due to aborted cmd, kicking-off EH\n");
blk_abort_request(scsi_cmd_to_rq(scp));
- goto out;
+ return;
}
scsi_done(scp); /* callback to mid level */
-out:
- sdebug_free_queued_cmd(sqcp);
}
/* When high resolution timer goes off this function is called. */
@@ -5648,50 +5630,32 @@ static void scsi_debug_slave_destroy(struct scsi_device *sdp)
sdp->hostdata = NULL;
}
-/* Returns true if the queued command memory should be freed by the caller. */
-static bool stop_qc_helper(struct sdebug_defer *sd_dp,
- enum sdeb_defer_type defer_t)
+/* Returns true if it is safe to complete @cmnd. */
+static bool scsi_debug_stop_cmnd(struct scsi_cmnd *cmnd)
{
+ struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmnd);
+ struct sdebug_defer *sd_dp = &sdsc->sd_dp;
+ enum sdeb_defer_type defer_t = READ_ONCE(sd_dp->defer_t);
+
+ lockdep_assert_held(&sdsc->lock);
+
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 0: /* Not active, it must have already run */
case 1: /* Was active, we've now cancelled */
default:
return true;
}
} else if (defer_t == SDEB_DEFER_WQ) {
- /* The caller must free qcmd if cancellation succeeds. */
- return cancel_work(&sd_dp->ew.work);
- } else if (defer_t == SDEB_DEFER_POLL) {
- return true;
+ /* Retry aborting later if the completion handler is running. */
+ return cancel_work(&sd_dp->ew.work) ||
+ !work_pending(&sd_dp->ew.work);
}
- return false;
-}
-
-
-static bool scsi_debug_stop_cmnd(struct scsi_cmnd *cmnd)
-{
- enum sdeb_defer_type l_defer_t;
- struct sdebug_defer *sd_dp;
- struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmnd);
- struct sdebug_queued_cmd *sqcp = TO_QUEUED_CMD(cmnd);
-
- lockdep_assert_held(&sdsc->lock);
-
- if (!sqcp)
- return false;
- sd_dp = &sqcp->sd_dp;
- l_defer_t = READ_ONCE(sd_dp->defer_t);
- ASSIGN_QUEUED_CMD(cmnd, NULL);
-
- if (stop_qc_helper(sd_dp, l_defer_t))
- sdebug_free_queued_cmd(sqcp);
-
return true;
}
@@ -5706,6 +5670,8 @@ static bool scsi_debug_abort_cmnd(struct scsi_cmnd *cmnd)
spin_lock_irqsave(&sdsc->lock, flags);
res = scsi_debug_stop_cmnd(cmnd);
+ if (res)
+ WRITE_ONCE(sdsc->sd_dp.defer_t, SDEB_DEFER_NONE);
spin_unlock_irqrestore(&sdsc->lock, flags);
return res;
@@ -5783,7 +5749,7 @@ static int scsi_debug_abort(struct scsi_cmnd *SCpnt)
return FAILED;
}
- return SUCCESS;
+ return ok ? SUCCESS : FAILED;
}
static bool scsi_debug_stop_all_queued_iter(struct request *rq, void *data)
@@ -6056,33 +6022,6 @@ 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;
-
- 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
@@ -6099,7 +6038,6 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmnd);
unsigned long flags;
u64 ns_from_boot = 0;
- struct sdebug_queued_cmd *sqcp;
struct scsi_device *sdp;
struct sdebug_defer *sd_dp;
@@ -6131,12 +6069,7 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
}
}
- sqcp = sdebug_alloc_queued_cmd(cmnd);
- if (!sqcp) {
- pr_err("%s no alloc\n", __func__);
- return SCSI_MLQUEUE_HOST_BUSY;
- }
- sd_dp = &sqcp->sd_dp;
+ sd_dp = &sdsc->sd_dp;
if (polled)
ns_from_boot = ktime_get_boottime_ns();
@@ -6184,7 +6117,6 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
if (kt <= d) { /* elapsed duration >= kt */
/* call scsi_done() from this thread */
- sdebug_free_queued_cmd(sqcp);
scsi_done(cmnd);
return 0;
}
@@ -6197,13 +6129,11 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
if (polled) {
spin_lock_irqsave(&sdsc->lock, flags);
sd_dp->cmpl_ts = ktime_add(ns_to_ktime(ns_from_boot), kt);
- ASSIGN_QUEUED_CMD(cmnd, sqcp);
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_POLL);
spin_unlock_irqrestore(&sdsc->lock, flags);
} else {
/* schedule the invocation of scsi_done() for a later time */
spin_lock_irqsave(&sdsc->lock, flags);
- ASSIGN_QUEUED_CMD(cmnd, sqcp);
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_HRT);
hrtimer_start(&sd_dp->hrt, kt, HRTIMER_MODE_REL_PINNED);
/*
@@ -6227,13 +6157,11 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
sd_dp->issuing_cpu = raw_smp_processor_id();
if (polled) {
spin_lock_irqsave(&sdsc->lock, flags);
- ASSIGN_QUEUED_CMD(cmnd, sqcp);
sd_dp->cmpl_ts = ns_to_ktime(ns_from_boot);
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_POLL);
spin_unlock_irqrestore(&sdsc->lock, flags);
} else {
spin_lock_irqsave(&sdsc->lock, flags);
- ASSIGN_QUEUED_CMD(cmnd, sqcp);
WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_WQ);
schedule_work(&sd_dp->ew.work);
spin_unlock_irqrestore(&sdsc->lock, flags);
@@ -7587,12 +7515,6 @@ 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) {
- ret = -ENOMEM;
- goto driver_unreg;
- }
-
sdebug_debugfs_root = debugfs_create_dir("scsi_debug", NULL);
if (IS_ERR_OR_NULL(sdebug_debugfs_root))
pr_info("%s: failed to create initial debugfs directory\n", __func__);
@@ -7619,8 +7541,6 @@ 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:
@@ -7636,7 +7556,6 @@ static void __exit scsi_debug_exit(void)
for (; k; k--)
sdebug_do_remove_host(true);
- kmem_cache_destroy(queued_cmd_cache);
driver_unregister(&sdebug_driverfs_driver);
bus_unregister(&pseudo_lld_bus);
root_device_unregister(pseudo_primary);
@@ -8018,7 +7937,6 @@ static bool sdebug_blk_mq_poll_iter(struct request *rq, void *opaque)
struct sdebug_defer *sd_dp;
u32 unique_tag = blk_mq_unique_tag(rq);
u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
- struct sdebug_queued_cmd *sqcp;
unsigned long flags;
int queue_num = data->queue_num;
ktime_t time;
@@ -8034,13 +7952,7 @@ static bool sdebug_blk_mq_poll_iter(struct request *rq, void *opaque)
time = ktime_get_boottime();
spin_lock_irqsave(&sdsc->lock, flags);
- sqcp = TO_QUEUED_CMD(cmd);
- if (!sqcp) {
- spin_unlock_irqrestore(&sdsc->lock, flags);
- return true;
- }
-
- sd_dp = &sqcp->sd_dp;
+ sd_dp = &sdsc->sd_dp;
if (READ_ONCE(sd_dp->defer_t) != SDEB_DEFER_POLL) {
spin_unlock_irqrestore(&sdsc->lock, flags);
return true;
@@ -8050,8 +7962,6 @@ static bool sdebug_blk_mq_poll_iter(struct request *rq, void *opaque)
spin_unlock_irqrestore(&sdsc->lock, flags);
return true;
}
-
- ASSIGN_QUEUED_CMD(cmd, NULL);
spin_unlock_irqrestore(&sdsc->lock, flags);
if (sdebug_statistics) {
@@ -8060,8 +7970,6 @@ static bool sdebug_blk_mq_poll_iter(struct request *rq, void *opaque)
atomic_inc(&sdebug_miss_cpus);
}
- sdebug_free_queued_cmd(sqcp);
-
scsi_done(cmd); /* callback to mid level */
(*data->num_entries)++;
return true;
@@ -8376,8 +8284,12 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
static int sdebug_init_cmd_priv(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
struct sdebug_scsi_cmd *sdsc = scsi_cmd_priv(cmd);
+ struct sdebug_defer *sd_dp = &sdsc->sd_dp;
spin_lock_init(&sdsc->lock);
+ 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);
return 0;
}
