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authorBart Van Assche <bart.vanassche@sandisk.com>2016-11-23 03:17:13 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2016-11-29 19:21:27 +0300
commit669f044170d8933c3d66d231b69ea97cb8447338 (patch)
tree7dfa2438e08cab47446b431a1e5990e58ef439f9 /drivers/scsi/scsi_transport_srp.c
parent27c3d76821a5f563cd3d760bfa7c8deb43f8d874 (diff)
downloadlinux-669f044170d8933c3d66d231b69ea97cb8447338.tar.xz
scsi: srp_transport: Move queuecommand() wait code to SCSI core
Additionally, rename srp_wait_for_queuecommand() into scsi_wait_for_queuecommand() and add a comment about the queuecommand() call from scsi_send_eh_cmnd(). Note: this patch changes scsi_internal_device_block from a function that did not sleep into a function that may sleep. This is fine for all callers of this function: * scsi_internal_device_block() is called from the mpt3sas device while that driver holds the ioc->dm_cmds.mutex. This means that the mpt3sas driver calls this function from thread context. * scsi_target_block() is called by __iscsi_block_session() from kernel thread context and with IRQs enabled. * The SRP transport code also calls scsi_target_block() from kernel thread context while sleeping is allowed. * The snic driver also calls scsi_target_block() from a context from which sleeping is allowed. The scsi_target_block() call namely occurs immediately after a scsi_flush_work() call. [mkp: s/shost/sdev/] Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Cc: James Bottomley <jejb@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Doug Ledford <dledford@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi_transport_srp.c')
-rw-r--r--drivers/scsi/scsi_transport_srp.c41
1 files changed, 6 insertions, 35 deletions
diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index 02cfc6b1ee5a..b87a78673f65 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -24,7 +24,6 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>
-#include <linux/delay.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
@@ -393,36 +392,6 @@ 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);
@@ -432,14 +401,17 @@ static void __rport_fail_io_fast(struct srp_rport *rport)
if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
return;
+ /*
+ * Call scsi_target_block() to wait for ongoing shost->queuecommand()
+ * calls before invoking i->f->terminate_rport_io().
+ */
+ scsi_target_block(rport->dev.parent);
scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
/* Involve the LLD if possible to terminate all I/O on the rport. */
i = to_srp_internal(shost->transportt);
- if (i->f->terminate_rport_io) {
- srp_wait_for_queuecommand(shost);
+ if (i->f->terminate_rport_io)
i->f->terminate_rport_io(rport);
- }
}
/**
@@ -567,7 +539,6 @@ int srp_reconnect_rport(struct srp_rport *rport)
if (res)
goto out;
scsi_target_block(&shost->shost_gendev);
- 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);