From 018d1dc9558e748e271cd1600c698f68cba3fb09 Mon Sep 17 00:00:00 2001 From: "Matthew R. Ochs" Date: Wed, 21 Oct 2015 15:13:21 -0500 Subject: [PATCH] cxlflash: Fix to avoid stall while waiting on TMF Borrowing the TMF waitq's spinlock causes a stall condition when waiting for the TMF to complete. To remedy, introduce our own spin lock to serialize TMF and use the appropriate wait services. Also add a timeout while waiting for a TMF completion. When a TMF times out, report back a failure such that a bigger hammer reset can occur. Signed-off-by: Matthew R. Ochs Signed-off-by: Manoj N. Kumar Reviewed-by: Brian King Reviewed-by: Tomas Henzl Signed-off-by: James Bottomley --- drivers/scsi/cxlflash/common.h | 1 + drivers/scsi/cxlflash/main.c | 55 ++++++++++++++++++++-------------- 2 files changed, 34 insertions(+), 22 deletions(-) diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h index b038ac7e76d9..7a0cb5c0dad4 100644 --- a/drivers/scsi/cxlflash/common.h +++ b/drivers/scsi/cxlflash/common.h @@ -124,6 +124,7 @@ struct cxlflash_cfg { struct list_head lluns; /* list of llun_info structs */ wait_queue_head_t tmf_waitq; + spinlock_t tmf_slock; bool tmf_active; wait_queue_head_t reset_waitq; enum cxlflash_state state; diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index 527ff85467ed..110037d6a1b6 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -249,11 +249,10 @@ static void cmd_complete(struct afu_cmd *cmd) scp->scsi_done(scp); if (cmd_is_tmf) { - spin_lock_irqsave(&cfg->tmf_waitq.lock, lock_flags); + spin_lock_irqsave(&cfg->tmf_slock, lock_flags); cfg->tmf_active = false; wake_up_all_locked(&cfg->tmf_waitq); - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, - lock_flags); + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); } } else complete(&cmd->cevent); @@ -420,6 +419,7 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) struct device *dev = &cfg->dev->dev; ulong lock_flags; int rc = 0; + ulong to; cmd = cmd_checkout(afu); if (unlikely(!cmd)) { @@ -428,15 +428,15 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) goto out; } - /* If a Task Management Function is active, do not send one more. - */ - spin_lock_irqsave(&cfg->tmf_waitq.lock, lock_flags); + /* When Task Management Function is active do not send another */ + spin_lock_irqsave(&cfg->tmf_slock, lock_flags); if (cfg->tmf_active) - wait_event_interruptible_locked_irq(cfg->tmf_waitq, - !cfg->tmf_active); + wait_event_interruptible_lock_irq(cfg->tmf_waitq, + !cfg->tmf_active, + cfg->tmf_slock); cfg->tmf_active = true; cmd->cmd_tmf = true; - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); cmd->rcb.ctx_id = afu->ctx_hndl; cmd->rcb.port_sel = port_sel; @@ -457,15 +457,24 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) rc = send_cmd(afu, cmd); if (unlikely(rc)) { cmd_checkin(cmd); - spin_lock_irqsave(&cfg->tmf_waitq.lock, lock_flags); + spin_lock_irqsave(&cfg->tmf_slock, lock_flags); cfg->tmf_active = false; - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); goto out; } - spin_lock_irqsave(&cfg->tmf_waitq.lock, lock_flags); - wait_event_interruptible_locked_irq(cfg->tmf_waitq, !cfg->tmf_active); - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); + spin_lock_irqsave(&cfg->tmf_slock, lock_flags); + to = msecs_to_jiffies(5000); + to = wait_event_interruptible_lock_irq_timeout(cfg->tmf_waitq, + !cfg->tmf_active, + cfg->tmf_slock, + to); + if (!to) { + cfg->tmf_active = false; + dev_err(dev, "%s: TMF timed out!\n", __func__); + rc = -1; + } + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); out: return rc; } @@ -512,16 +521,17 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) get_unaligned_be32(&((u32 *)scp->cmnd)[2]), get_unaligned_be32(&((u32 *)scp->cmnd)[3])); - /* If a Task Management Function is active, wait for it to complete + /* + * If a Task Management Function is active, wait for it to complete * before continuing with regular commands. */ - spin_lock_irqsave(&cfg->tmf_waitq.lock, lock_flags); + spin_lock_irqsave(&cfg->tmf_slock, lock_flags); if (cfg->tmf_active) { - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); rc = SCSI_MLQUEUE_HOST_BUSY; goto out; } - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); switch (cfg->state) { case STATE_RESET: @@ -713,11 +723,12 @@ static void cxlflash_remove(struct pci_dev *pdev) /* If a Task Management Function is active, wait for it to complete * before continuing with remove. */ - spin_lock_irqsave(&cfg->tmf_waitq.lock, lock_flags); + spin_lock_irqsave(&cfg->tmf_slock, lock_flags); if (cfg->tmf_active) - wait_event_interruptible_locked_irq(cfg->tmf_waitq, - !cfg->tmf_active); - spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); + wait_event_interruptible_lock_irq(cfg->tmf_waitq, + !cfg->tmf_active, + cfg->tmf_slock); + spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags); cfg->state = STATE_FAILTERM; cxlflash_stop_term_user_contexts(cfg); -- 2.39.5