From 6e40de8b6b3cfa7288bb4a1fee2c7173f53b7345 Mon Sep 17 00:00:00 2001 From: Tyrel Datwyler Date: Thu, 2 May 2019 19:50:57 -0500 Subject: scsi: ibmvscsi: redo driver work thread to use enum action states The current implemenation relies on two flags in the driver's private host structure to signal the need for a host reset or to reenable the CRQ after a LPAR migration. This patch does away with those flags and introduces a single action flag and defined enums for the supported kthread work actions. Lastly, the if/else logic is replaced with a switch statement. Signed-off-by: Tyrel Datwyler Signed-off-by: Martin K. Petersen --- drivers/scsi/ibmvscsi/ibmvscsi.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers/scsi/ibmvscsi/ibmvscsi.h') diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h index 3a7875575616..04bcbc832dc9 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.h +++ b/drivers/scsi/ibmvscsi/ibmvscsi.h @@ -88,13 +88,18 @@ struct event_pool { dma_addr_t iu_token; }; +enum ibmvscsi_host_action { + IBMVSCSI_HOST_ACTION_NONE = 0, + IBMVSCSI_HOST_ACTION_RESET, + IBMVSCSI_HOST_ACTION_REENABLE, +}; + /* all driver data associated with a host adapter */ struct ibmvscsi_host_data { struct list_head host_list; atomic_t request_limit; int client_migrated; - int reset_crq; - int reenable_crq; + enum ibmvscsi_host_action action; struct device *dev; struct event_pool pool; struct crq_queue queue; -- cgit v1.2.3 From aa343c695aa59f03f31a2f989b8c977a727e46e3 Mon Sep 17 00:00:00 2001 From: Tyrel Datwyler Date: Thu, 2 May 2019 19:50:58 -0500 Subject: scsi: ibmvscsi: fix tripping of blk_mq_run_hw_queue WARN_ON After a successful SRP login response we call scsi_unblock_requests() to kick any pending IOs. The callback to process this SRP response happens in a tasklet and therefore is in softirq context. The result of such is that when blk-mq is enabled, it is no longer safe to call scsi_unblock_requests() from this context. The result of duing so triggers the following WARN_ON splat in dmesg after a host reset or CRQ reenablement. WARNING: CPU: 0 PID: 0 at block/blk-mq.c:1375 __blk_mq_run_hw_queue+0x120/0x180 Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc8 #4 NIP [c0000000009771e0] __blk_mq_run_hw_queue+0x120/0x180 LR [c000000000977484] __blk_mq_delay_run_hw_queue+0x244/0x250 Call Trace: __blk_mq_delay_run_hw_queue+0x244/0x250 blk_mq_run_hw_queue+0x8c/0x1c0 blk_mq_run_hw_queues+0x60/0x90 scsi_run_queue+0x1e4/0x3b0 scsi_run_host_queues+0x48/0x80 login_rsp+0xb0/0x100 ibmvscsi_handle_crq+0x30c/0x3e0 ibmvscsi_task+0x54/0xe0 tasklet_action_common.isra.3+0xc4/0x1a0 __do_softirq+0x174/0x3f4 irq_exit+0xf0/0x120 __do_irq+0xb0/0x210 call_do_irq+0x14/0x24 do_IRQ+0x9c/0x130 hardware_interrupt_common+0x14c/0x150 This patch fixes the issue by introducing a new host action for unblocking the scsi requests in our seperate work thread. Signed-off-by: Tyrel Datwyler Signed-off-by: Martin K. Petersen --- drivers/scsi/ibmvscsi/ibmvscsi.c | 5 ++++- drivers/scsi/ibmvscsi/ibmvscsi.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/scsi/ibmvscsi/ibmvscsi.h') diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index 8df82c58e7b9..727c31dc11a0 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -1179,7 +1179,8 @@ static void login_rsp(struct srp_event_struct *evt_struct) be32_to_cpu(evt_struct->xfer_iu->srp.login_rsp.req_lim_delta)); /* If we had any pending I/Os, kick them */ - scsi_unblock_requests(hostdata->host); + hostdata->action = IBMVSCSI_HOST_ACTION_UNBLOCK; + wake_up(&hostdata->work_wait_q); } /** @@ -2123,6 +2124,7 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata) spin_lock_irqsave(hostdata->host->host_lock, flags); switch (hostdata->action) { case IBMVSCSI_HOST_ACTION_NONE: + case IBMVSCSI_HOST_ACTION_UNBLOCK: break; case IBMVSCSI_HOST_ACTION_RESET: spin_unlock_irqrestore(hostdata->host->host_lock, flags); @@ -2164,6 +2166,7 @@ static int __ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata) return 0; case IBMVSCSI_HOST_ACTION_RESET: case IBMVSCSI_HOST_ACTION_REENABLE: + case IBMVSCSI_HOST_ACTION_UNBLOCK: default: break; } diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h index 04bcbc832dc9..d9bf502334ba 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.h +++ b/drivers/scsi/ibmvscsi/ibmvscsi.h @@ -92,6 +92,7 @@ enum ibmvscsi_host_action { IBMVSCSI_HOST_ACTION_NONE = 0, IBMVSCSI_HOST_ACTION_RESET, IBMVSCSI_HOST_ACTION_REENABLE, + IBMVSCSI_HOST_ACTION_UNBLOCK, }; /* all driver data associated with a host adapter */ -- cgit v1.2.3