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scsi_transport_srp: Introduce srp_wait_for_queuecommand()

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Introduce the helper function srp_wait_for_queuecommand().
Move the definition of scsi_request_fn_active(). Add a comment
above srp_wait_for_queuecommand() that support for scsi-mq needs
to be added.

This patch does not change any functionality. A second call to
srp_wait_for_queuecommand() will be introduced in the next patch.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: James Bottomley <JBottomley@Odin.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.13
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Bart Van Assche 2015-05-18 13:22:19 +02:00 committed by Doug Ledford
parent e26081808e
commit be34c62ddf
1 changed files with 31 additions and 23 deletions
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54
drivers/scsi/scsi_transport_srp.c
View file

@ -396,6 +396,36 @@ static void srp_reconnect_work(struct work_struct *work)
}
}
/**
* scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
* @shost: SCSI host for which to count the number of scsi_request_fn() callers.
*
* To do: add support for scsi-mq in this function.
*/
static int scsi_request_fn_active(struct Scsi_Host *shost)
{
struct scsi_device *sdev;
struct request_queue *q;
int request_fn_active = 0;
shost_for_each_device(sdev, shost) {
q = sdev->request_queue;
spin_lock_irq(q->queue_lock);
request_fn_active += q->request_fn_active;
spin_unlock_irq(q->queue_lock);
}
return request_fn_active;
}
/* Wait until ongoing shost->hostt->queuecommand() calls have finished. */
static void srp_wait_for_queuecommand(struct Scsi_Host *shost)
{
while (scsi_request_fn_active(shost))
msleep(20);
}
static void __rport_fail_io_fast(struct srp_rport *rport)
{
struct Scsi_Host *shost = rport_to_shost(rport);
@ -503,27 +533,6 @@ void srp_start_tl_fail_timers(struct srp_rport *rport)
}
EXPORT_SYMBOL(srp_start_tl_fail_timers);
/**
* scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
* @shost: SCSI host for which to count the number of scsi_request_fn() callers.
*/
static int scsi_request_fn_active(struct Scsi_Host *shost)
{
struct scsi_device *sdev;
struct request_queue *q;
int request_fn_active = 0;
shost_for_each_device(sdev, shost) {
q = sdev->request_queue;
spin_lock_irq(q->queue_lock);
request_fn_active += q->request_fn_active;
spin_unlock_irq(q->queue_lock);
}
return request_fn_active;
}
/**
* srp_reconnect_rport() - reconnect to an SRP target port
* @rport: SRP target port.
@ -559,8 +568,7 @@ int srp_reconnect_rport(struct srp_rport *rport)
if (res)
goto out;
scsi_target_block(&shost->shost_gendev);
while (scsi_request_fn_active(shost))
msleep(20);
srp_wait_for_queuecommand(shost);
res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
pr_debug("%s (state %d): transport.reconnect() returned %d\n",
dev_name(&shost->shost_gendev), rport->state, res);