From c7c4e7ff8047e43c45628b85ac200582e9404c39 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 21 Feb 2013 17:19:04 +0000 Subject: [PATCH] IB/srp: Avoid endless SCSI error handling loop If a SCSI command times out it is passed to the SCSI error handler. The SCSI error handler will try to abort the commands that timed out. If aborting fails, a device reset will be attempted. If the device reset also fails a host reset will be attempted. If the host reset also fails the whole procedure will be repeated. srp_abort() and srp_reset_device() fail for a QP in the error state. srp_reset_host() fails after host removal has started. Hence if the SCSI error handler gets invoked after host removal has started and with the QP in the error state an endless loop will be triggered. Modify the SCSI error handling functions in ib_srp as follows: - Abort SCSI commands properly even if the QP is in the error state. - Make srp_reset_host() reset SCSI requests even after host removal has already started or if reconnecting fails. Signed-off-by: Bart Van Assche Acked-by: David Dillow Cc: # 3.8 Signed-off-by: Roland Dreier --- drivers/infiniband/ulp/srp/ib_srp.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index 263325848462..8a7eb9f98a0c 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -700,23 +700,24 @@ static int srp_reconnect_target(struct srp_target_port *target) struct Scsi_Host *shost = target->scsi_host; int i, ret; - if (target->state != SRP_TARGET_LIVE) - return -EAGAIN; - scsi_target_block(&shost->shost_gendev); srp_disconnect_target(target); /* - * Now get a new local CM ID so that we avoid confusing the - * target in case things are really fouled up. + * Now get a new local CM ID so that we avoid confusing the target in + * case things are really fouled up. Doing so also ensures that all CM + * callbacks will have finished before a new QP is allocated. */ ret = srp_new_cm_id(target); - if (ret) - goto unblock; - - ret = srp_create_target_ib(target); - if (ret) - goto unblock; + /* + * Whether or not creating a new CM ID succeeded, create a new + * QP. This guarantees that all completion callback function + * invocations have finished before request resetting starts. + */ + if (ret == 0) + ret = srp_create_target_ib(target); + else + srp_create_target_ib(target); for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) { struct srp_request *req = &target->req_ring[i]; @@ -728,9 +729,9 @@ static int srp_reconnect_target(struct srp_target_port *target) for (i = 0; i < SRP_SQ_SIZE; ++i) list_add(&target->tx_ring[i]->list, &target->free_tx); - ret = srp_connect_target(target); + if (ret == 0) + ret = srp_connect_target(target); -unblock: scsi_target_unblock(&shost->shost_gendev, ret == 0 ? SDEV_RUNNING : SDEV_TRANSPORT_OFFLINE); @@ -1739,7 +1740,7 @@ static int srp_abort(struct scsi_cmnd *scmnd) shost_printk(KERN_ERR, target->scsi_host, "SRP abort called\n"); - if (!req || target->qp_in_error || !srp_claim_req(target, req, scmnd)) + if (!req || !srp_claim_req(target, req, scmnd)) return FAILED; srp_send_tsk_mgmt(target, req->index, scmnd->device->lun, SRP_TSK_ABORT_TASK); -- 2.30.2