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[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 <htejun@gmail.com>
This commit is contained in:
Tejun Heo 2006-05-15 20:58:05 +09:00
parent f69499f42c
commit f686bcb807
4 changed files with 91 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
drivers/scsi/libata-core.c
View File

@ -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);

27
drivers/scsi/libata-eh.c
View File

@ -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 */

2
drivers/scsi/libata.h
View File

@ -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__ */

27
include/linux/libata.h
View File

@ -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.