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ata: libata-eh: avoid unnecessary calls to ata_scsi_port_error_handler()

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When handling SCSI command timeouts, if we had no actual command
timeouts (either because the command was a deferred qc or the completion
path won the race with ata_scsi_cmd_error_handler()), we do not need to
go through a port error handling, as there was in fact no errors at all.

Modify ata_scsi_cmd_error_handler() to return the number of commands
that timed out and use this return value in ata_scsi_error() to call
ata_scsi_port_error_handler() only if we had command timeouts, or if
the port EH has already been scheduled due to failed commands.
Otherwise, simply call scsi_eh_flush_done_q() to finish the completed
commands without running the full port error handling.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
This commit is contained in:
Damien Le Moal
2026-02-24 11:06:38 +09:00
committed by Niklas Cassel
parent db1d3cfaf3
commit 46a9d97069
2 changed files with 21 additions and 10 deletions
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28
drivers/ata/libata-eh.c
View File

@@ -560,21 +560,27 @@ void ata_scsi_error(struct Scsi_Host *host)
{
struct ata_port *ap = ata_shost_to_port(host);
unsigned long flags;
int nr_timedout;
LIST_HEAD(eh_work_q);
spin_lock_irqsave(host->host_lock, flags);
list_splice_init(&host->eh_cmd_q, &eh_work_q);
spin_unlock_irqrestore(host->host_lock, flags);
ata_scsi_cmd_error_handler(host, ap, &eh_work_q);
/*
* First check what errors we got with ata_scsi_cmd_error_handler().
* If we had no command timeouts and EH is not scheduled for this port,
* meaning that we do not have any failed command, then there is no
* need to go through the full port error handling. We only need to
* flush the completed commands we have.
*/
nr_timedout = ata_scsi_cmd_error_handler(host, ap, &eh_work_q);
if (nr_timedout || ata_port_eh_scheduled(ap))
ata_scsi_port_error_handler(host, ap);
else
scsi_eh_flush_done_q(&ap->eh_done_q);
/* If we timed raced normal completion and there is nothing to
recover nr_timedout == 0 why exactly are we doing error recovery ? */
ata_scsi_port_error_handler(host, ap);
/* finish or retry handled scmd's and clean up */
WARN_ON(!list_empty(&eh_work_q));
}
/**
@@ -586,9 +592,11 @@ void ata_scsi_error(struct Scsi_Host *host)
* process the given list of commands and return those finished to the
* ap->eh_done_q. This function is the first part of the libata error
* handler which processes a given list of failed commands.
*
* Return the number of commands that timed out.
*/
void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
struct list_head *eh_work_q)
int ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
struct list_head *eh_work_q)
{
int i;
unsigned long flags;
@@ -678,6 +686,8 @@ void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
ap->eh_tries = ATA_EH_MAX_TRIES;
spin_unlock_irqrestore(ap->lock, flags);
return nr_timedout;
}
EXPORT_SYMBOL(ata_scsi_cmd_error_handler);

3
include/linux/libata.h
View File

@@ -1225,7 +1225,8 @@ extern int ata_ncq_prio_enable(struct ata_port *ap, struct scsi_device *sdev,
extern struct ata_device *ata_dev_pair(struct ata_device *adev);
int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev);
extern void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap);
extern void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap, struct list_head *eh_q);
int ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
struct list_head *eh_q);
/*
* SATA specific code - drivers/ata/libata-sata.c