Re: [PATCH] ata: libata-eh: avoid unnecessary calls to ata_scsi_port_error_handler()

[Niklas Cassel <cassel@kernel.org>]

On Tue, Feb 24, 2026 at 11:06:38AM +0900, Damien Le Moal wrote:
> 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: Niklas Cassel <cassel@kernel.org>


> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index db87c99e4189..c872d1f9f43b 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -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);
> +extern int ata_scsi_cmd_error_handler(struct Scsi_Host *host,
> +				struct ata_port *ap, struct list_head *eh_q);

Nit: we could drop the extern while touching this line anyway.


Kind regards,
Niklas