On Tue, Mar 6, 2018 at 11:47 PM, Jason Yan <yanai...@huawei.com> wrote:
> When ata device doing EH, some commands still attached with tasks are not
> passed to libata when abort failed or recover failed, so libata did not
> handle these commands. After these commands done, sas task is freed, but
> ata qc is not freed. This will cause ata qc leak and trigger a warning
> like below:
>
> WARNING: CPU: 0 PID: 28512 at drivers/ata/libata-eh.c:4037
> ata_eh_finish+0xb4/0xcc
> CPU: 0 PID: 28512 Comm: kworker/u32:2 Tainted: G     W  OE 4.14.0#1
> ......
> Call trace:
> [<ffff0000088b7bd0>] ata_eh_finish+0xb4/0xcc
> [<ffff0000088b8420>] ata_do_eh+0xc4/0xd8
> [<ffff0000088b8478>] ata_std_error_handler+0x44/0x8c
> [<ffff0000088b8068>] ata_scsi_port_error_handler+0x480/0x694
> [<ffff000008875fc4>] async_sas_ata_eh+0x4c/0x80
> [<ffff0000080f6be8>] async_run_entry_fn+0x4c/0x170
> [<ffff0000080ebd70>] process_one_work+0x144/0x390
> [<ffff0000080ec100>] worker_thread+0x144/0x418
> [<ffff0000080f2c98>] kthread+0x10c/0x138
> [<ffff0000080855dc>] ret_from_fork+0x10/0x18
>
> If ata qc leaked too many, ata tag allocation will fail and io blocked
> for ever.
>
> As suggested by Dan Williams, defer ata device commands to libata and
> merge sas_eh_finish_cmd() with sas_eh_defer_cmd(). libata will handle
> ata qcs correctly after this.
>
> Signed-off-by: Jason Yan <yanai...@huawei.com>
> CC: Xiaofei Tan <tanxiao...@huawei.com>
> CC: John Garry <john.ga...@huawei.com>
> CC: Dan Williams <dan.j.willi...@intel.com>
> ---
>  drivers/scsi/libsas/sas_scsi_host.c | 30 ++++++++++--------------------
>  1 file changed, 10 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/scsi/libsas/sas_scsi_host.c 
> b/drivers/scsi/libsas/sas_scsi_host.c
> index 6de9681ace82..fd76436b289c 100644
> --- a/drivers/scsi/libsas/sas_scsi_host.c
> +++ b/drivers/scsi/libsas/sas_scsi_host.c
> @@ -223,6 +223,7 @@ int sas_queuecommand(struct Scsi_Host *host, struct 
> scsi_cmnd *cmd)
>  static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
>  {
>         struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host);
> +       struct domain_device *dev = cmd_to_domain_dev(cmd);
>         struct sas_task *task = TO_SAS_TASK(cmd);
>
>         /* At this point, we only get called following an actual abort
> @@ -231,6 +232,11 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
>          */
>         sas_end_task(cmd, task);

This patch looks good, just need a comment here about why it is ok to
short circuit this routine in the dev_is_sata() case.

>
> +       if (dev_is_sata(dev)) {
> +               list_move_tail(&cmd->eh_entry, &sas_ha->eh_ata_q);
> +               return;
> +       }
> +

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