From b3fe628da2898cf1387105026dfed551ecc25de5 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 14 Mar 2014 13:54:11 +0100 Subject: [PATCH] IB/srp: Fix a race condition between failing I/O and I/O completion Avoid that srp_terminate_io() can access req->scmnd after it has been cleared by the I/O completion code. Do this by protecting req->scmnd accesses from srp_terminate_io() via locking Signed-off-by: Bart Van Assche Acked-by: Sagi Grimberg Signed-off-by: Roland Dreier --- drivers/infiniband/ulp/srp/ib_srp.c | 33 +++++++++++++++++++---------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index a64e469db116..66a908bf3fb9 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -783,6 +783,7 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd, * srp_claim_req - Take ownership of the scmnd associated with a request. * @target: SRP target port. * @req: SRP request. + * @sdev: If not NULL, only take ownership for this SCSI device. * @scmnd: If NULL, take ownership of @req->scmnd. If not NULL, only take * ownership of @req->scmnd if it equals @scmnd. * @@ -791,16 +792,17 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd, */ static struct scsi_cmnd *srp_claim_req(struct srp_target_port *target, struct srp_request *req, + struct scsi_device *sdev, struct scsi_cmnd *scmnd) { unsigned long flags; spin_lock_irqsave(&target->lock, flags); - if (!scmnd) { + if (req->scmnd && + (!sdev || req->scmnd->device == sdev) && + (!scmnd || req->scmnd == scmnd)) { scmnd = req->scmnd; req->scmnd = NULL; - } else if (req->scmnd == scmnd) { - req->scmnd = NULL; } else { scmnd = NULL; } @@ -827,9 +829,10 @@ static void srp_free_req(struct srp_target_port *target, } static void srp_finish_req(struct srp_target_port *target, - struct srp_request *req, int result) + struct srp_request *req, struct scsi_device *sdev, + int result) { - struct scsi_cmnd *scmnd = srp_claim_req(target, req, NULL); + struct scsi_cmnd *scmnd = srp_claim_req(target, req, sdev, NULL); if (scmnd) { srp_free_req(target, req, scmnd, 0); @@ -841,11 +844,20 @@ static void srp_finish_req(struct srp_target_port *target, static void srp_terminate_io(struct srp_rport *rport) { struct srp_target_port *target = rport->lld_data; + struct Scsi_Host *shost = target->scsi_host; + struct scsi_device *sdev; int i; + /* + * Invoking srp_terminate_io() while srp_queuecommand() is running + * is not safe. Hence the warning statement below. + */ + shost_for_each_device(sdev, shost) + WARN_ON_ONCE(sdev->request_queue->request_fn_active); + for (i = 0; i < target->req_ring_size; ++i) { struct srp_request *req = &target->req_ring[i]; - srp_finish_req(target, req, DID_TRANSPORT_FAILFAST << 16); + srp_finish_req(target, req, NULL, DID_TRANSPORT_FAILFAST << 16); } } @@ -882,7 +894,7 @@ static int srp_rport_reconnect(struct srp_rport *rport) for (i = 0; i < target->req_ring_size; ++i) { struct srp_request *req = &target->req_ring[i]; - srp_finish_req(target, req, DID_RESET << 16); + srp_finish_req(target, req, NULL, DID_RESET << 16); } INIT_LIST_HEAD(&target->free_tx); @@ -1290,7 +1302,7 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp) complete(&target->tsk_mgmt_done); } else { req = &target->req_ring[rsp->tag]; - scmnd = srp_claim_req(target, req, NULL); + scmnd = srp_claim_req(target, req, NULL, NULL); if (!scmnd) { shost_printk(KERN_ERR, target->scsi_host, "Null scmnd for RSP w/tag %016llx\n", @@ -2008,7 +2020,7 @@ static int srp_abort(struct scsi_cmnd *scmnd) shost_printk(KERN_ERR, target->scsi_host, "SRP abort called\n"); - if (!req || !srp_claim_req(target, req, scmnd)) + if (!req || !srp_claim_req(target, req, NULL, scmnd)) return SUCCESS; if (srp_send_tsk_mgmt(target, req->index, scmnd->device->lun, SRP_TSK_ABORT_TASK) == 0) @@ -2039,8 +2051,7 @@ static int srp_reset_device(struct scsi_cmnd *scmnd) for (i = 0; i < target->req_ring_size; ++i) { struct srp_request *req = &target->req_ring[i]; - if (req->scmnd && req->scmnd->device == scmnd->device) - srp_finish_req(target, req, DID_RESET << 16); + srp_finish_req(target, req, scmnd->device, DID_RESET << 16); } return SUCCESS; -- 2.39.2