From: Tejun Heo Date: Mon, 15 May 2006 11:58:05 +0000 (+0900) Subject: [PATCH] libata-eh-fw: implement new EH scheduling via error completion X-Git-Url: http://drtracing.org/?a=commitdiff_plain;ds=sidebyside;h=f686bcb8078ac7505ec88818886c2c72639f4fc5;p=deliverable%2Flinux.git [PATCH] libata-eh-fw: implement new EH scheduling via error completion There are several ways a qc can get schedule for EH in new EH. This patch implements one of them - completing a qc with ATA_QCFLAG_FAILED set or with non-zero qc->err_mask. ALL such qc's are examined by EH. New EH schedules a qc for EH from completion iff ->error_handler is implemented, qc is marked as failed or qc->err_mask is non-zero and the command is not an internal command (internal cmd is handled via ->post_internal_cmd). The EH scheduling itself is performed by asking SCSI midlayer to schedule EH for the specified scmd. For drivers implementing old-EH, nothing changes. As this change makes ata_qc_complete() rather large, it's not inlined anymore and __ata_qc_complete() is exported to other parts of libata for later use. Signed-off-by: Tejun Heo --- diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 1c34c1427aa3..1f5c3270992a 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -4123,6 +4123,66 @@ void __ata_qc_complete(struct ata_queued_cmd *qc) qc->complete_fn(qc); } +/** + * ata_qc_complete - Complete an active ATA command + * @qc: Command to complete + * @err_mask: ATA Status register contents + * + * Indicate to the mid and upper layers that an ATA + * command has completed, with either an ok or not-ok status. + * + * LOCKING: + * spin_lock_irqsave(host_set lock) + */ +void ata_qc_complete(struct ata_queued_cmd *qc) +{ + struct ata_port *ap = qc->ap; + + /* XXX: New EH and old EH use different mechanisms to + * synchronize EH with regular execution path. + * + * In new EH, a failed qc is marked with ATA_QCFLAG_FAILED. + * Normal execution path is responsible for not accessing a + * failed qc. libata core enforces the rule by returning NULL + * from ata_qc_from_tag() for failed qcs. + * + * Old EH depends on ata_qc_complete() nullifying completion + * requests if ATA_QCFLAG_EH_SCHEDULED is set. Old EH does + * not synchronize with interrupt handler. Only PIO task is + * taken care of. + */ + if (ap->ops->error_handler) { + WARN_ON(ap->flags & ATA_FLAG_FROZEN); + + if (unlikely(qc->err_mask)) + qc->flags |= ATA_QCFLAG_FAILED; + + if (unlikely(qc->flags & ATA_QCFLAG_FAILED)) { + if (!ata_tag_internal(qc->tag)) { + /* always fill result TF for failed qc */ + ap->ops->tf_read(ap, &qc->result_tf); + ata_qc_schedule_eh(qc); + return; + } + } + + /* read result TF if requested */ + if (qc->flags & ATA_QCFLAG_RESULT_TF) + ap->ops->tf_read(ap, &qc->result_tf); + + __ata_qc_complete(qc); + } else { + if (qc->flags & ATA_QCFLAG_EH_SCHEDULED) + return; + + /* read result TF if failed or requested */ + if (qc->err_mask || qc->flags & ATA_QCFLAG_RESULT_TF) + ap->ops->tf_read(ap, &qc->result_tf); + + __ata_qc_complete(qc); + } +} + static inline int ata_should_dma_map(struct ata_queued_cmd *qc) { struct ata_port *ap = qc->ap; @@ -5245,7 +5305,7 @@ EXPORT_SYMBOL_GPL(ata_device_add); EXPORT_SYMBOL_GPL(ata_host_set_remove); EXPORT_SYMBOL_GPL(ata_sg_init); EXPORT_SYMBOL_GPL(ata_sg_init_one); -EXPORT_SYMBOL_GPL(__ata_qc_complete); +EXPORT_SYMBOL_GPL(ata_qc_complete); EXPORT_SYMBOL_GPL(ata_qc_issue_prot); EXPORT_SYMBOL_GPL(ata_tf_load); EXPORT_SYMBOL_GPL(ata_tf_read); diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c index 959a1cdffac2..471846fe4b73 100644 --- a/drivers/scsi/libata-eh.c +++ b/drivers/scsi/libata-eh.c @@ -210,6 +210,33 @@ void ata_eng_timeout(struct ata_port *ap) DPRINTK("EXIT\n"); } +/** + * ata_qc_schedule_eh - schedule qc for error handling + * @qc: command to schedule error handling for + * + * Schedule error handling for @qc. EH will kick in as soon as + * other commands are drained. + * + * LOCKING: + * spin_lock_irqsave(host_set lock) + */ +void ata_qc_schedule_eh(struct ata_queued_cmd *qc) +{ + struct ata_port *ap = qc->ap; + + WARN_ON(!ap->ops->error_handler); + + qc->flags |= ATA_QCFLAG_FAILED; + qc->ap->flags |= ATA_FLAG_EH_PENDING; + + /* The following will fail if timeout has already expired. + * ata_scsi_error() takes care of such scmds on EH entry. + * Note that ATA_QCFLAG_FAILED is unconditionally set after + * this function completes. + */ + scsi_req_abort_cmd(qc->scsicmd); +} + static void ata_eh_scsidone(struct scsi_cmnd *scmd) { /* nada */ diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h index c9ff83bbcfae..52622b7f8a9e 100644 --- a/drivers/scsi/libata.h +++ b/drivers/scsi/libata.h @@ -57,6 +57,7 @@ extern int ata_do_reset(struct ata_port *ap, ata_reset_fn_t reset, unsigned int *classes); extern void ata_qc_free(struct ata_queued_cmd *qc); extern void ata_qc_issue(struct ata_queued_cmd *qc); +extern void __ata_qc_complete(struct ata_queued_cmd *qc); extern int ata_check_atapi_dma(struct ata_queued_cmd *qc); extern void ata_dev_select(struct ata_port *ap, unsigned int device, unsigned int wait, unsigned int can_sleep); @@ -101,5 +102,6 @@ extern void ata_scsi_rbuf_fill(struct ata_scsi_args *args, /* libata-eh.c */ extern enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd); extern void ata_scsi_error(struct Scsi_Host *host); +extern void ata_qc_schedule_eh(struct ata_queued_cmd *qc); #endif /* __LIBATA_H__ */ diff --git a/include/linux/libata.h b/include/linux/libata.h index bfcefdca0616..6023f324e68e 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -605,7 +605,7 @@ extern void ata_bmdma_start (struct ata_queued_cmd *qc); extern void ata_bmdma_stop(struct ata_queued_cmd *qc); extern u8 ata_bmdma_status(struct ata_port *ap); extern void ata_bmdma_irq_clear(struct ata_port *ap); -extern void __ata_qc_complete(struct ata_queued_cmd *qc); +extern void ata_qc_complete(struct ata_queued_cmd *qc); extern void ata_scsi_simulate(struct ata_device *dev, struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)); extern int ata_std_bios_param(struct scsi_device *sdev, @@ -882,31 +882,6 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc) qc->result_tf.feature = 0; } -/** - * ata_qc_complete - Complete an active ATA command - * @qc: Command to complete - * @err_mask: ATA Status register contents - * - * Indicate to the mid and upper layers that an ATA - * command has completed, with either an ok or not-ok status. - * - * LOCKING: - * spin_lock_irqsave(host_set lock) - */ -static inline void ata_qc_complete(struct ata_queued_cmd *qc) -{ - struct ata_port *ap = qc->ap; - - if (unlikely(qc->flags & ATA_QCFLAG_EH_SCHEDULED)) - return; - - /* read result TF if failed or requested */ - if (qc->err_mask || qc->flags & ATA_QCFLAG_RESULT_TF) - ap->ops->tf_read(ap, &qc->result_tf); - - __ata_qc_complete(qc); -} - /** * ata_irq_on - Enable interrupts on a port. * @ap: Port on which interrupts are enabled.