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scsi: ibmvfc: Define per-queue state/list locks
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Define per-queue locks for protecting queue state and event pool sent/free
lists. The evt list lock is initially redundant but it allows the driver to
be modified in the follow-up patches to relax the queue locking around
submissions and completions.

Link: https://lore.kernel.org/r/20210106201835.1053593-4-tyreld@linux.ibm.com
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Tyrel Datwyler authored and Martin K. Petersen committed Jan 8, 2021
1 parent e4b26f3 commit 57e80e0
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Showing 2 changed files with 80 additions and 20 deletions.
93 changes: 74 additions & 19 deletions drivers/scsi/ibmvscsi/ibmvfc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -176,8 +176,9 @@ static void ibmvfc_trc_start(struct ibmvfc_event *evt)
struct ibmvfc_mad_common *mad = &evt->iu.mad_common;
struct ibmvfc_fcp_cmd_iu *iu = ibmvfc_get_fcp_iu(vhost, vfc_cmd);
struct ibmvfc_trace_entry *entry;
int index = atomic_inc_return(&vhost->trace_index) & IBMVFC_TRACE_INDEX_MASK;

entry = &vhost->trace[vhost->trace_index++];
entry = &vhost->trace[index];
entry->evt = evt;
entry->time = jiffies;
entry->fmt = evt->crq.format;
Expand Down Expand Up @@ -211,8 +212,10 @@ static void ibmvfc_trc_end(struct ibmvfc_event *evt)
struct ibmvfc_mad_common *mad = &evt->xfer_iu->mad_common;
struct ibmvfc_fcp_cmd_iu *iu = ibmvfc_get_fcp_iu(vhost, vfc_cmd);
struct ibmvfc_fcp_rsp *rsp = ibmvfc_get_fcp_rsp(vhost, vfc_cmd);
struct ibmvfc_trace_entry *entry = &vhost->trace[vhost->trace_index++];
struct ibmvfc_trace_entry *entry;
int index = atomic_inc_return(&vhost->trace_index) & IBMVFC_TRACE_INDEX_MASK;

entry = &vhost->trace[index];
entry->evt = evt;
entry->time = jiffies;
entry->fmt = evt->crq.format;
Expand Down Expand Up @@ -805,6 +808,7 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));

spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock(vhost->crq.q_lock);
vhost->state = IBMVFC_NO_CRQ;
vhost->logged_in = 0;

Expand All @@ -821,6 +825,7 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
dev_warn(vhost->dev, "Partner adapter not ready\n");
else if (rc != 0)
dev_warn(vhost->dev, "Couldn't register crq (rc=%d)\n", rc);
spin_unlock(vhost->crq.q_lock);
spin_unlock_irqrestore(vhost->host->host_lock, flags);

return rc;
Expand Down Expand Up @@ -853,10 +858,16 @@ static int ibmvfc_valid_event(struct ibmvfc_event_pool *pool,
static void ibmvfc_free_event(struct ibmvfc_event *evt)
{
struct ibmvfc_event_pool *pool = &evt->queue->evt_pool;
unsigned long flags;

BUG_ON(!ibmvfc_valid_event(pool, evt));
BUG_ON(atomic_inc_return(&evt->free) != 1);

spin_lock_irqsave(&evt->queue->l_lock, flags);
list_add_tail(&evt->queue_list, &evt->queue->free);
if (evt->eh_comp)
complete(evt->eh_comp);
spin_unlock_irqrestore(&evt->queue->l_lock, flags);
}

/**
Expand All @@ -875,12 +886,27 @@ static void ibmvfc_scsi_eh_done(struct ibmvfc_event *evt)
cmnd->scsi_done(cmnd);
}

if (evt->eh_comp)
complete(evt->eh_comp);

ibmvfc_free_event(evt);
}

/**
* ibmvfc_complete_purge - Complete failed command list
* @purge_list: list head of failed commands
*
* This function runs completions on commands to fail as a result of a
* host reset or platform migration. Caller must hold host_lock.
**/
static void ibmvfc_complete_purge(struct list_head *purge_list)
{
struct ibmvfc_event *evt, *pos;

list_for_each_entry_safe(evt, pos, purge_list, queue_list) {
list_del(&evt->queue_list);
ibmvfc_trc_end(evt);
evt->done(evt);
}
}

/**
* ibmvfc_fail_request - Fail request with specified error code
* @evt: ibmvfc event struct
Expand All @@ -897,10 +923,7 @@ static void ibmvfc_fail_request(struct ibmvfc_event *evt, int error_code)
} else
evt->xfer_iu->mad_common.status = cpu_to_be16(IBMVFC_MAD_DRIVER_FAILED);

list_del(&evt->queue_list);
del_timer(&evt->timer);
ibmvfc_trc_end(evt);
evt->done(evt);
}

/**
Expand All @@ -914,10 +937,14 @@ static void ibmvfc_fail_request(struct ibmvfc_event *evt, int error_code)
static void ibmvfc_purge_requests(struct ibmvfc_host *vhost, int error_code)
{
struct ibmvfc_event *evt, *pos;
unsigned long flags;

ibmvfc_dbg(vhost, "Purging all requests\n");
spin_lock_irqsave(&vhost->crq.l_lock, flags);
list_for_each_entry_safe(evt, pos, &vhost->crq.sent, queue_list)
ibmvfc_fail_request(evt, error_code);
list_splice_init(&vhost->crq.sent, &vhost->purge);
spin_unlock_irqrestore(&vhost->crq.l_lock, flags);
}

/**
Expand Down Expand Up @@ -1314,6 +1341,7 @@ static int ibmvfc_init_event_pool(struct ibmvfc_host *vhost,

INIT_LIST_HEAD(&queue->sent);
INIT_LIST_HEAD(&queue->free);
spin_lock_init(&queue->l_lock);

for (i = 0; i < pool->size; ++i) {
struct ibmvfc_event *evt = &pool->events[i];
Expand Down Expand Up @@ -1368,11 +1396,14 @@ static void ibmvfc_free_event_pool(struct ibmvfc_host *vhost,
static struct ibmvfc_event *ibmvfc_get_event(struct ibmvfc_queue *queue)
{
struct ibmvfc_event *evt;
unsigned long flags;

spin_lock_irqsave(&queue->l_lock, flags);
BUG_ON(list_empty(&queue->free));
evt = list_entry(queue->free.next, struct ibmvfc_event, queue_list);
atomic_set(&evt->free, 0);
list_del(&evt->queue_list);
spin_unlock_irqrestore(&queue->l_lock, flags);
return evt;
}

Expand Down Expand Up @@ -1506,6 +1537,7 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
struct ibmvfc_host *vhost, unsigned long timeout)
{
__be64 *crq_as_u64 = (__be64 *) &evt->crq;
unsigned long flags;
int rc;

/* Copy the IU into the transfer area */
Expand All @@ -1517,19 +1549,22 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
else
BUG();

list_add_tail(&evt->queue_list, &evt->queue->sent);
timer_setup(&evt->timer, ibmvfc_timeout, 0);

if (timeout) {
evt->timer.expires = jiffies + (timeout * HZ);
add_timer(&evt->timer);
}

spin_lock_irqsave(&evt->queue->l_lock, flags);
list_add_tail(&evt->queue_list, &evt->queue->sent);

mb();

if ((rc = ibmvfc_send_crq(vhost, be64_to_cpu(crq_as_u64[0]),
be64_to_cpu(crq_as_u64[1])))) {
list_del(&evt->queue_list);
spin_unlock_irqrestore(&evt->queue->l_lock, flags);
del_timer(&evt->timer);

/* If send_crq returns H_CLOSED, return SCSI_MLQUEUE_HOST_BUSY.
Expand All @@ -1554,8 +1589,10 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
evt->xfer_iu->mad_common.status = cpu_to_be16(IBMVFC_MAD_CRQ_ERROR);

evt->done(evt);
} else
} else {
spin_unlock_irqrestore(&evt->queue->l_lock, flags);
ibmvfc_trc_start(evt);
}

return 0;
}
Expand Down Expand Up @@ -1663,9 +1700,6 @@ static void ibmvfc_scsi_done(struct ibmvfc_event *evt)
cmnd->scsi_done(cmnd);
}

if (evt->eh_comp)
complete(evt->eh_comp);

ibmvfc_free_event(evt);
}

Expand Down Expand Up @@ -2219,28 +2253,28 @@ static int ibmvfc_wait_for_ops(struct ibmvfc_host *vhost, void *device,
ENTER;
do {
wait = 0;
spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock_irqsave(&vhost->crq.l_lock, flags);
list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
if (match(evt, device)) {
evt->eh_comp = &comp;
wait++;
}
}
spin_unlock_irqrestore(vhost->host->host_lock, flags);
spin_unlock_irqrestore(&vhost->crq.l_lock, flags);

if (wait) {
timeout = wait_for_completion_timeout(&comp, timeout);

if (!timeout) {
wait = 0;
spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock_irqsave(&vhost->crq.l_lock, flags);
list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
if (match(evt, device)) {
evt->eh_comp = NULL;
wait++;
}
}
spin_unlock_irqrestore(vhost->host->host_lock, flags);
spin_unlock_irqrestore(&vhost->crq.l_lock, flags);
if (wait)
dev_err(vhost->dev, "Timed out waiting for aborted commands\n");
LEAVE;
Expand Down Expand Up @@ -2277,14 +2311,16 @@ static int ibmvfc_cancel_all(struct scsi_device *sdev, int type)
u16 status;

ENTER;
spin_lock_irqsave(vhost->host->host_lock, flags);
found_evt = NULL;
spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock(&vhost->crq.l_lock);
list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
if (evt->cmnd && evt->cmnd->device == sdev) {
found_evt = evt;
break;
}
}
spin_unlock(&vhost->crq.l_lock);

if (!found_evt) {
if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
Expand Down Expand Up @@ -2414,14 +2450,16 @@ static int ibmvfc_abort_task_set(struct scsi_device *sdev)
unsigned long flags, timeout = IBMVFC_ABORT_TIMEOUT;
int rsp_code = 0;

spin_lock_irqsave(vhost->host->host_lock, flags);
found_evt = NULL;
spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock(&vhost->crq.l_lock);
list_for_each_entry(evt, &vhost->crq.sent, queue_list) {
if (evt->cmnd && evt->cmnd->device == sdev) {
found_evt = evt;
break;
}
}
spin_unlock(&vhost->crq.l_lock);

if (!found_evt) {
if (vhost->log_level > IBMVFC_DEFAULT_LOG_LEVEL)
Expand Down Expand Up @@ -2935,7 +2973,9 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost)
}

del_timer(&evt->timer);
spin_lock(&evt->queue->l_lock);
list_del(&evt->queue_list);
spin_unlock(&evt->queue->l_lock);
ibmvfc_trc_end(evt);
evt->done(evt);
}
Expand Down Expand Up @@ -3328,6 +3368,7 @@ static void ibmvfc_tasklet(void *data)
int done = 0;

spin_lock_irqsave(vhost->host->host_lock, flags);
spin_lock(vhost->crq.q_lock);
while (!done) {
/* Pull all the valid messages off the async CRQ */
while ((async = ibmvfc_next_async_crq(vhost)) != NULL) {
Expand Down Expand Up @@ -3358,6 +3399,7 @@ static void ibmvfc_tasklet(void *data)
done = 1;
}

spin_unlock(vhost->crq.q_lock);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
}

Expand Down Expand Up @@ -4734,6 +4776,7 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
struct ibmvfc_target *tgt;
unsigned long flags;
struct fc_rport *rport;
LIST_HEAD(purge);
int rc;

ibmvfc_log_ae(vhost, vhost->events_to_log);
Expand All @@ -4746,6 +4789,8 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
break;
case IBMVFC_HOST_ACTION_RESET:
vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
list_splice_init(&vhost->purge, &purge);
ibmvfc_complete_purge(&purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
rc = ibmvfc_reset_crq(vhost);
spin_lock_irqsave(vhost->host->host_lock, flags);
Expand All @@ -4759,6 +4804,8 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
break;
case IBMVFC_HOST_ACTION_REENABLE:
vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
list_splice_init(&vhost->purge, &purge);
ibmvfc_complete_purge(&purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
rc = ibmvfc_reenable_crq_queue(vhost);
spin_lock_irqsave(vhost->host->host_lock, flags);
Expand Down Expand Up @@ -4936,6 +4983,9 @@ static int ibmvfc_alloc_queue(struct ibmvfc_host *vhost,
size_t fmt_size;

ENTER;
spin_lock_init(&queue->_lock);
queue->q_lock = &queue->_lock;

switch (fmt) {
case IBMVFC_CRQ_FMT:
fmt_size = sizeof(*queue->msgs.crq);
Expand Down Expand Up @@ -5098,6 +5148,7 @@ static int ibmvfc_alloc_mem(struct ibmvfc_host *vhost)

vhost->trace = kcalloc(IBMVFC_NUM_TRACE_ENTRIES,
sizeof(struct ibmvfc_trace_entry), GFP_KERNEL);
atomic_set(&vhost->trace_index, -1);

if (!vhost->trace)
goto free_disc_buffer;
Expand Down Expand Up @@ -5214,6 +5265,7 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)

vhost = shost_priv(shost);
INIT_LIST_HEAD(&vhost->targets);
INIT_LIST_HEAD(&vhost->purge);
sprintf(vhost->name, IBMVFC_NAME);
vhost->host = shost;
vhost->dev = dev;
Expand Down Expand Up @@ -5298,6 +5350,7 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
static int ibmvfc_remove(struct vio_dev *vdev)
{
struct ibmvfc_host *vhost = dev_get_drvdata(&vdev->dev);
LIST_HEAD(purge);
unsigned long flags;

ENTER;
Expand All @@ -5315,6 +5368,8 @@ static int ibmvfc_remove(struct vio_dev *vdev)

spin_lock_irqsave(vhost->host->host_lock, flags);
ibmvfc_purge_requests(vhost, DID_ERROR);
list_splice_init(&vhost->purge, &purge);
ibmvfc_complete_purge(&purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
ibmvfc_free_event_pool(vhost, &vhost->crq);

Expand Down
7 changes: 6 additions & 1 deletion drivers/scsi/ibmvscsi/ibmvfc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -768,10 +768,13 @@ struct ibmvfc_queue {
dma_addr_t msg_token;
enum ibmvfc_msg_fmt fmt;
int size, cur;
spinlock_t _lock;
spinlock_t *q_lock;

struct ibmvfc_event_pool evt_pool;
struct list_head sent;
struct list_head free;
spinlock_t l_lock;
};

enum ibmvfc_host_action {
Expand Down Expand Up @@ -808,11 +811,13 @@ struct ibmvfc_host {
enum ibmvfc_host_action action;
#define IBMVFC_NUM_TRACE_INDEX_BITS 8
#define IBMVFC_NUM_TRACE_ENTRIES (1 << IBMVFC_NUM_TRACE_INDEX_BITS)
#define IBMVFC_TRACE_INDEX_MASK (IBMVFC_NUM_TRACE_ENTRIES - 1)
#define IBMVFC_TRACE_SIZE (sizeof(struct ibmvfc_trace_entry) * IBMVFC_NUM_TRACE_ENTRIES)
struct ibmvfc_trace_entry *trace;
u32 trace_index:IBMVFC_NUM_TRACE_INDEX_BITS;
atomic_t trace_index;
int num_targets;
struct list_head targets;
struct list_head purge;
struct device *dev;
struct dma_pool *sg_pool;
mempool_t *tgt_pool;
Expand Down

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