From: Douglas Gilbert <dgilbert@interlog.com>
Date: Wed, 10 Jan 2018 16:57:31 -0500
Subject: [PATCH] scsi: scsi_debug: delay stress fix
Git-commit: 10bde980ac18da7859591f3a30ddac881f83a2cf
Patch-mainline: v4.16-rc1
References: bsc#1118139
Introduce a state enum into sdebug_defer objects to indicate which, if
any, defer method has been used with the associated command. Also add 2
bools to indicate which of the defer methods has been initialized. Those
objects are re-used but the initialization only needs to be done
once. This simplifies command cancellation handling.
Now the delay associated with a deferred response of a command cannot be
changed (once started) by changing the delay (and ndelay) parameters in
sysfs. Command aborts and driver shutdown are still honoured immediately
when received.
[mkp: applied by hand]
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/scsi_debug.c | 72 ++++++++++++++++++++++++++++++-----------------
1 file changed, 46 insertions(+), 26 deletions(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index b8f83c4e2c81..a5986dae9020 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -267,12 +267,18 @@ struct sdebug_host_info {
#define to_sdebug_host(d) \
container_of(d, struct sdebug_host_info, dev)
+enum sdeb_defer_type {SDEB_DEFER_NONE = 0, SDEB_DEFER_HRT = 1,
+ SDEB_DEFER_WQ = 2};
+
struct sdebug_defer {
struct hrtimer hrt;
struct execute_work ew;
int sqa_idx; /* index of sdebug_queue array */
int qc_idx; /* index of sdebug_queued_cmd array within sqa_idx */
int issuing_cpu;
+ bool init_hrt;
+ bool init_wq;
+ enum sdeb_defer_type defer_t;
};
struct sdebug_queued_cmd {
@@ -3748,6 +3754,7 @@ static void sdebug_q_cmd_complete(struct sdebug_defer *sd_dp)
struct scsi_cmnd *scp;
struct sdebug_dev_info *devip;
+ sd_dp->defer_t = SDEB_DEFER_NONE;
qc_idx = sd_dp->qc_idx;
sqp = sdebug_q_arr + sd_dp->sqa_idx;
if (sdebug_statistics) {
@@ -3932,13 +3939,14 @@ static void scsi_debug_slave_destroy(struct scsi_device *sdp)
}
}
-static void stop_qc_helper(struct sdebug_defer *sd_dp)
+static void stop_qc_helper(struct sdebug_defer *sd_dp,
+ enum sdeb_defer_type defer_t)
{
if (!sd_dp)
return;
- if ((sdebug_jdelay > 0) || (sdebug_ndelay > 0))
+ if (defer_t == SDEB_DEFER_HRT)
hrtimer_cancel(&sd_dp->hrt);
- else if (sdebug_jdelay < 0)
+ else if (defer_t == SDEB_DEFER_WQ)
cancel_work_sync(&sd_dp->ew.work);
}
@@ -3948,6 +3956,7 @@ static bool stop_queued_cmnd(struct scsi_cmnd *cmnd)
{
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_dev_info *devip;
@@ -3971,8 +3980,13 @@ static bool stop_queued_cmnd(struct scsi_cmnd *cmnd)
atomic_dec(&devip->num_in_q);
sqcp->a_cmnd = NULL;
sd_dp = sqcp->sd_dp;
+ if (sd_dp) {
+ l_defer_t = sd_dp->defer_t;
+ 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);
+ stop_qc_helper(sd_dp, l_defer_t);
clear_bit(k, sqp->in_use_bm);
return true;
}
@@ -3987,6 +4001,7 @@ static void stop_all_queued(void)
{
unsigned long iflags;
int j, k;
+ enum sdeb_defer_type l_defer_t;
struct sdebug_queue *sqp;
struct sdebug_queued_cmd *sqcp;
struct sdebug_dev_info *devip;
@@ -4005,8 +4020,13 @@ static void stop_all_queued(void)
atomic_dec(&devip->num_in_q);
sqcp->a_cmnd = NULL;
sd_dp = sqcp->sd_dp;
+ if (sd_dp) {
+ l_defer_t = sd_dp->defer_t;
+ 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);
+ stop_qc_helper(sd_dp, l_defer_t);
clear_bit(k, sqp->in_use_bm);
spin_lock_irqsave(&sqp->qc_lock, iflags);
}
@@ -4258,7 +4278,7 @@ static void setup_inject(struct sdebug_queue *sqp,
* SCSI_MLQUEUE_HOST_BUSY if temporarily out of resources.
*/
static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
- int scsi_result, int delta_jiff)
+ int scsi_result, int delta_jiff, int ndelay)
{
unsigned long iflags;
int k, num_in_q, qdepth, inject;
@@ -4336,17 +4356,20 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
if (unlikely(sdebug_every_nth && sdebug_any_injecting_opt))
setup_inject(sqp, sqcp);
- if (delta_jiff > 0 || sdebug_ndelay > 0) {
+ if (sd_dp == NULL) {
+ sd_dp = kzalloc(sizeof(*sd_dp), GFP_ATOMIC);
+ if (sd_dp == NULL)
+ return SCSI_MLQUEUE_HOST_BUSY;
+ }
+ if (delta_jiff > 0 || ndelay > 0) {
ktime_t kt;
if (delta_jiff > 0) {
kt = ns_to_ktime((u64)delta_jiff * (NSEC_PER_SEC / HZ));
} else
- kt = sdebug_ndelay;
- if (NULL == sd_dp) {
- sd_dp = kzalloc(sizeof(*sd_dp), GFP_ATOMIC);
- if (NULL == sd_dp)
- return SCSI_MLQUEUE_HOST_BUSY;
+ kt = ndelay;
+ 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);
@@ -4356,12 +4379,11 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
}
if (sdebug_statistics)
sd_dp->issuing_cpu = raw_smp_processor_id();
+ sd_dp->defer_t = SDEB_DEFER_HRT;
hrtimer_start(&sd_dp->hrt, kt, HRTIMER_MODE_REL_PINNED);
} else { /* jdelay < 0, use work queue */
- if (NULL == sd_dp) {
- sd_dp = kzalloc(sizeof(*sqcp->sd_dp), GFP_ATOMIC);
- if (NULL == sd_dp)
- return SCSI_MLQUEUE_HOST_BUSY;
+ 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;
@@ -4369,6 +4391,7 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
}
if (sdebug_statistics)
sd_dp->issuing_cpu = raw_smp_processor_id();
+ sd_dp->defer_t = SDEB_DEFER_WQ;
schedule_work(&sd_dp->ew.work);
}
if (unlikely((SDEBUG_OPT_Q_NOISE & sdebug_opts) &&
@@ -4615,9 +4638,6 @@ static ssize_t delay_store(struct device_driver *ddp, const char *buf,
}
}
if (res > 0) {
- /* make sure sdebug_defer instances get
- * re-allocated for new delay variant */
- free_all_queued();
sdebug_jdelay = jdelay;
sdebug_ndelay = 0;
}
@@ -4658,9 +4678,6 @@ static ssize_t ndelay_store(struct device_driver *ddp, const char *buf,
}
}
if (res > 0) {
- /* make sure sdebug_defer instances get
- * re-allocated for new delay variant */
- free_all_queued();
sdebug_ndelay = ndelay;
sdebug_jdelay = ndelay ? JDELAY_OVERRIDDEN
: DEF_JDELAY;
@@ -5702,12 +5719,15 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
errsts = r_pfp(scp, devip);
fini:
- return schedule_resp(scp, devip, errsts,
- ((F_DELAY_OVERR & flags) ? 0 : sdebug_jdelay));
+ if (F_DELAY_OVERR & flags)
+ return schedule_resp(scp, devip, errsts, 0, 0);
+ else
+ return schedule_resp(scp, devip, errsts, sdebug_jdelay,
+ sdebug_ndelay);
check_cond:
- return schedule_resp(scp, devip, check_condition_result, 0);
+ return schedule_resp(scp, devip, check_condition_result, 0, 0);
err_out:
- return schedule_resp(scp, NULL, DID_NO_CONNECT << 16, 0);
+ return schedule_resp(scp, NULL, DID_NO_CONNECT << 16, 0, 0);
}
static struct scsi_host_template sdebug_driver_template = {
--
2.12.3