From 669f044170d8933c3d66d231b69ea97cb8447338 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 22 Nov 2016 16:17:13 -0800 Subject: 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 Reviewed-by: Sagi Grimberg Reviewed-by: Martin K. Petersen Cc: James Bottomley Cc: Christoph Hellwig Cc: Doug Ledford Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_transport_srp.c | 41 ++++++--------------------------------- 1 file changed, 6 insertions(+), 35 deletions(-) (limited to 'drivers/scsi/scsi_transport_srp.c') 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 #include #include -#include #include #include @@ -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); -- cgit v1.2.3