On Mon, 2015-08-10 at 12:09 -0500, Matthew R. Ochs wrote: > Introduce support for enhanced I/O error handling.
This needs more description of what you're doing. What's the overall approach? There seems to be a new limbo queue thats created stall things while the device is in error state. That should be described here. > Signed-off-by: Matthew R. Ochs <[email protected]> > Signed-off-by: Manoj N. Kumar <[email protected]> > --- > drivers/scsi/cxlflash/Kconfig | 2 +- > drivers/scsi/cxlflash/common.h | 11 ++- > drivers/scsi/cxlflash/main.c | 166 > ++++++++++++++++++++++++++++++++++++++--- > drivers/scsi/cxlflash/main.h | 4 + > 4 files changed, 170 insertions(+), 13 deletions(-) > > diff --git a/drivers/scsi/cxlflash/Kconfig b/drivers/scsi/cxlflash/Kconfig > index c707508..c052104 100644 > --- a/drivers/scsi/cxlflash/Kconfig > +++ b/drivers/scsi/cxlflash/Kconfig > @@ -4,7 +4,7 @@ > > config CXLFLASH > tristate "Support for IBM CAPI Flash" > - depends on PCI && SCSI && CXL > + depends on PCI && SCSI && CXL && EEH > default m > help > Allows CAPI Accelerated IO to Flash > diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h > index fe86bfe..7e663f4 100644 > --- a/drivers/scsi/cxlflash/common.h > +++ b/drivers/scsi/cxlflash/common.h > @@ -76,6 +76,12 @@ enum cxlflash_init_state { > INIT_STATE_SCSI > }; > > +enum cxlflash_state { > + STATE_NORMAL, /* Normal running state, everything good */ > + STATE_LIMBO, /* Limbo running state, trying to reset/recover */ > + STATE_FAILTERM /* Failed/terminating state, error out users/threads */ > +}; > + > /* > * Each context has its own set of resource handles that is visible > * only from that context. > @@ -91,8 +97,6 @@ struct cxlflash_cfg { > > ulong cxlflash_regs_pci; > > - wait_queue_head_t eeh_waitq; > - > struct work_struct work_q; > enum cxlflash_init_state init_state; > enum cxlflash_lr_state lr_state; > @@ -105,7 +109,8 @@ struct cxlflash_cfg { > > wait_queue_head_t tmf_waitq; > bool tmf_active; > - u8 err_recovery_active:1; > + wait_queue_head_t limbo_waitq; > + enum cxlflash_state state; > }; > > struct afu_cmd { > diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c > index 76a7286..18359d4 100644 > --- a/drivers/scsi/cxlflash/main.c > +++ b/drivers/scsi/cxlflash/main.c > @@ -380,6 +380,18 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, > struct scsi_cmnd *scp) > } > spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); > > + switch (cfg->state) { > + case STATE_LIMBO: > + pr_debug_ratelimited("%s: device in limbo!\n", __func__); > + rc = SCSI_MLQUEUE_HOST_BUSY; So if the client gets BUSY, it should retry until it suceeds or gets a terminal failure? > + goto out; > + case STATE_FAILTERM: > + pr_debug_ratelimited("%s: device has failed!\n", __func__); > + goto error; error is only used here, so there is no need for a goto. > + default: > + break; > + } > + > cmd = cxlflash_cmd_checkout(afu); > if (unlikely(!cmd)) { > pr_err("%s: could not get a free command\n", __func__); > @@ -428,6 +440,10 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, > struct scsi_cmnd *scp) > > out: > return rc; > +error: > + scp->result = (DID_NO_CONNECT << 16); > + scp->scsi_done(scp); > + return 0; 0 is success. That doesn't seem right for an error. > } > > /** > @@ -455,9 +471,21 @@ static int cxlflash_eh_device_reset_handler(struct > scsi_cmnd *scp) > get_unaligned_be32(&((u32 *)scp->cmnd)[2]), > get_unaligned_be32(&((u32 *)scp->cmnd)[3])); > > - rcr = send_tmf(afu, scp, TMF_LUN_RESET); > - if (unlikely(rcr)) > + switch (cfg->state) { > + case STATE_NORMAL: > + rcr = send_tmf(afu, scp, TMF_LUN_RESET); > + if (unlikely(rcr)) > + rc = FAILED; > + break; > + case STATE_LIMBO: > + wait_event(cfg->limbo_waitq, cfg->state != STATE_LIMBO); So we wait here till we are our of limbo? > + if (cfg->state == STATE_NORMAL) > + break; > + /* fall through */ > + default: > rc = FAILED; > + break; > + } > > pr_debug("%s: returning rc=%d\n", __func__, rc); > return rc; > @@ -487,11 +515,27 @@ static int cxlflash_eh_host_reset_handler(struct > scsi_cmnd *scp) > get_unaligned_be32(&((u32 *)scp->cmnd)[2]), > get_unaligned_be32(&((u32 *)scp->cmnd)[3])); > > - rcr = cxlflash_afu_reset(cfg); > - if (rcr == 0) > - rc = SUCCESS; > - else > + switch (cfg->state) { > + case STATE_NORMAL: > + cfg->state = STATE_LIMBO; > + scsi_block_requests(cfg->host); > + > + rcr = cxlflash_afu_reset(cfg); > + if (!rcr) > + rc = FAILED; This is some sort of recovery once we get back into normal state? Can you comment what you're doing here? > + cfg->state = STATE_NORMAL; > + wake_up_all(&cfg->limbo_waitq); > + scsi_unblock_requests(cfg->host); Now we actually go to normal? > + break; > + case STATE_LIMBO: > + wait_event(cfg->limbo_waitq, cfg->state != STATE_LIMBO); Wait here till we are out of limbo? What happens if that never occurs? > + if (cfg->state == STATE_NORMAL) > + break; > + /* fall through */ > + default: > rc = FAILED; > + break; > + } > > pr_debug("%s: returning rc=%d\n", __func__, rc); > return rc; > @@ -642,7 +686,7 @@ static void cxlflash_wait_for_pci_err_recovery(struct > cxlflash_cfg *cfg) > struct pci_dev *pdev = cfg->dev; > > if (pci_channel_offline(pdev)) > - wait_event_timeout(cfg->eeh_waitq, > + wait_event_timeout(cfg->limbo_waitq, > !pci_channel_offline(pdev), > CXLFLASH_PCI_ERROR_RECOVERY_TIMEOUT); > } > @@ -825,6 +869,8 @@ static void cxlflash_remove(struct pci_dev *pdev) > !cfg->tmf_active); > spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags); > > + cfg->state = STATE_FAILTERM; > + > switch (cfg->init_state) { > case INIT_STATE_SCSI: > scsi_remove_host(cfg->host); > @@ -1879,6 +1925,8 @@ static int init_afu(struct cxlflash_cfg *cfg) > struct afu *afu = cfg->afu; > struct device *dev = &cfg->dev->dev; > > + cxl_perst_reloads_same_image(cfg->cxl_afu, true); > + > rc = init_mc(cfg); > if (rc) { > dev_err(dev, "%s: call to init_mc failed, rc=%d!\n", > @@ -2021,6 +2069,12 @@ void cxlflash_wait_resp(struct afu *afu, struct > afu_cmd *cmd) > * the sync. This design point requires calling threads to not be on > interrupt > * context due to the possibility of sleeping during concurrent sync > operations. > * > + * AFU sync operations are only necessary and allowed when the device is > + * operating normally. When not operating normally, sync requests can occur > as > + * part of cleaning up resources associated with an adapter prior to removal. > + * In this scenario, these requests are simply ignored (safe due to the AFU > + * going away). > + * What about if we are in limbo state and it comes back? > * Return: > * 0 on success > * -1 on failure > @@ -2028,11 +2082,17 @@ void cxlflash_wait_resp(struct afu *afu, struct > afu_cmd *cmd) > int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t ctx_hndl_u, > res_hndl_t res_hndl_u, u8 mode) > { > + struct cxlflash_cfg *cfg = afu->parent; > struct afu_cmd *cmd = NULL; > int rc = 0; > int retry_cnt = 0; > static DEFINE_MUTEX(sync_active); > > + if (cfg->state != STATE_NORMAL) { > + pr_debug("%s: Sync not required! (%u)\n", __func__, cfg->state); > + return 0; > + } > + > mutex_lock(&sync_active); > retry: > cmd = cxlflash_cmd_checkout(afu); > @@ -2122,6 +2182,11 @@ static void cxlflash_worker_thread(struct work_struct > *work) > int port; > ulong lock_flags; > > + /* Avoid MMIO if the device has failed */ > + > + if (cfg->state != STATE_NORMAL) > + return; > + > spin_lock_irqsave(cfg->host->host_lock, lock_flags); > > if (cfg->lr_state == LINK_RESET_REQUIRED) { > @@ -2200,10 +2265,9 @@ static int cxlflash_probe(struct pci_dev *pdev, > cfg->dev = pdev; > cfg->dev_id = (struct pci_device_id *)dev_id; > cfg->mcctx = NULL; > - cfg->err_recovery_active = 0; > > init_waitqueue_head(&cfg->tmf_waitq); > - init_waitqueue_head(&cfg->eeh_waitq); > + init_waitqueue_head(&cfg->limbo_waitq); > > INIT_WORK(&cfg->work_q, cxlflash_worker_thread); > cfg->lr_state = LINK_RESET_INVALID; > @@ -2259,6 +2323,89 @@ out_remove: > goto out; > } > > +/** > + * cxlflash_pci_error_detected() - called when a PCI error is detected > + * @pdev: PCI device struct. > + * @state: PCI channel state. > + * > + * Return: PCI_ERS_RESULT_NEED_RESET or PCI_ERS_RESULT_DISCONNECT > + */ > +static pci_ers_result_t cxlflash_pci_error_detected(struct pci_dev *pdev, > + pci_channel_state_t state) > +{ > + struct cxlflash_cfg *cfg = pci_get_drvdata(pdev); > + > + pr_debug("%s: pdev=%p state=%u\n", __func__, pdev, state); > + > + switch (state) { > + case pci_channel_io_frozen: > + cfg->state = STATE_LIMBO; > + > + /* Turn off legacy I/O */ > + scsi_block_requests(cfg->host); > + > + term_mc(cfg, UNDO_START); > + stop_afu(cfg); > + > + return PCI_ERS_RESULT_NEED_RESET; > + case pci_channel_io_perm_failure: > + cfg->state = STATE_FAILTERM; > + wake_up_all(&cfg->limbo_waitq); > + scsi_unblock_requests(cfg->host); > + return PCI_ERS_RESULT_DISCONNECT; > + default: > + break; > + } > + return PCI_ERS_RESULT_NEED_RESET; > +} > + > +/** > + * cxlflash_pci_slot_reset() - called when PCI slot has been reset > + * @pdev: PCI device struct. > + * > + * This routine is called by the pci error recovery code after the PCI > + * slot has been reset, just before we should resume normal operations. > + * > + * Return: PCI_ERS_RESULT_RECOVERED or PCI_ERS_RESULT_DISCONNECT > + */ > +static pci_ers_result_t cxlflash_pci_slot_reset(struct pci_dev *pdev) > +{ > + int rc = 0; > + struct cxlflash_cfg *cfg = pci_get_drvdata(pdev); > + struct device *dev = &cfg->dev->dev; > + > + pr_debug("%s: pdev=%p\n", __func__, pdev); > + > + rc = init_afu(cfg); > + if (unlikely(rc)) { > + dev_err(dev, "%s: EEH recovery failed! (%d)\n", __func__, rc); > + return PCI_ERS_RESULT_DISCONNECT; > + } > + > + return PCI_ERS_RESULT_RECOVERED; > +} > + > +/** > + * cxlflash_pci_resume() - called when normal operation can resume > + * @pdev: PCI device struct > + */ > +static void cxlflash_pci_resume(struct pci_dev *pdev) > +{ > + struct cxlflash_cfg *cfg = pci_get_drvdata(pdev); > + > + pr_debug("%s: pdev=%p\n", __func__, pdev); > + > + cfg->state = STATE_NORMAL; > + wake_up_all(&cfg->limbo_waitq); > + scsi_unblock_requests(cfg->host); > +} > + > +static const struct pci_error_handlers cxlflash_err_handler = { > + .error_detected = cxlflash_pci_error_detected, > + .slot_reset = cxlflash_pci_slot_reset, > + .resume = cxlflash_pci_resume, > +}; > + > /* > * PCI device structure > */ > @@ -2267,6 +2414,7 @@ static struct pci_driver cxlflash_driver = { > .id_table = cxlflash_pci_table, > .probe = cxlflash_probe, > .remove = cxlflash_remove, > + .err_handler = &cxlflash_err_handler, > }; > > /** > diff --git a/drivers/scsi/cxlflash/main.h b/drivers/scsi/cxlflash/main.h > index 7f890cc..7232536 100644 > --- a/drivers/scsi/cxlflash/main.h > +++ b/drivers/scsi/cxlflash/main.h > @@ -101,4 +101,8 @@ struct asyc_intr_info { > #define LINK_RESET 0x02 > }; > > +#ifndef CONFIG_CXL_EEH > +#define cxl_perst_reloads_same_image(_a, _b) do { } while (0) > +#endif > + > #endif /* _CXLFLASH_MAIN_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
