Hello Hannes,
sry that I only now reply to the other patches of the series.
On Wed, Mar 01, 2017 at 10:15:17AM +0100, Hannes Reinecke wrote:
> To detect if a failed command has been retried we must not
> clear scmd->eh_eflags when EH finishes.
> The flag should be persistent throughout the lifetime
> of the command.
>
> Reviewed-by: Johannes Thumshirn <jthumsh...@suse.de>
> Signed-off-by: Hannes Reinecke <h...@suse.de>
> ---
> Documentation/scsi/scsi_eh.txt | 14 +++++++-------
> drivers/scsi/libsas/sas_scsi_host.c | 2 --
> drivers/scsi/scsi_error.c | 4 ++--
> include/scsi/scsi_eh.h | 1 +
> 4 files changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/scsi/scsi_eh.txt b/Documentation/scsi/scsi_eh.txt
> index 37eca00..4edb9c1c 100644
> --- a/Documentation/scsi/scsi_eh.txt
> +++ b/Documentation/scsi/scsi_eh.txt
> @@ -105,11 +105,14 @@ function
>
> 2. If the host supports asynchronous completion (as indicated by the
> no_async_abort setting in the host template) scsi_abort_command()
> - is invoked to schedule an asynchrous abort. If that fails
> - Step #3 is taken.
> + is invoked to schedule an asynchrous abort.
> + Asynchronous abort are not invoked for commands which the
> + SCSI_EH_ABORT_SCHEDULED flag is set (this indicates that the command
> + already had been aborted once, and this is a retry which failed),
> + or when the EH deadline is expired. In these case Step #3 is taken.
>
> - 2. scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD) is invoked for the
> - command. See [1-3] for more information.
> + 3. scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD) is invoked for the
> + command. See [1-4] for more information.
>
> [1-3] Asynchronous command aborts
>
> @@ -263,7 +266,6 @@ scmd->allowed.
>
> 3. scmd recovered
> ACTION: scsi_eh_finish_cmd() is invoked to EH-finish scmd
> - - clear scmd->eh_eflags
> - scsi_setup_cmd_retry()
> - move from local eh_work_q to local eh_done_q
> LOCKING: none
> @@ -456,8 +458,6 @@ except for #1 must be implemented by
> eh_strategy_handler().
>
> - shost->host_failed is zero.
>
> - - Each scmd's eh_eflags field is cleared.
> -
> - Each scmd is in such a state that scsi_setup_cmd_retry() on the
> scmd doesn't make any difference.
>
> diff --git a/drivers/scsi/libsas/sas_scsi_host.c
> b/drivers/scsi/libsas/sas_scsi_host.c
> index ee6b39a..87e5079 100644
> --- a/drivers/scsi/libsas/sas_scsi_host.c
> +++ b/drivers/scsi/libsas/sas_scsi_host.c
> @@ -613,8 +613,6 @@ static void sas_eh_handle_sas_errors(struct Scsi_Host
> *shost, struct list_head *
> SAS_DPRINTK("trying to find task 0x%p\n", task);
> res = sas_scsi_find_task(task);
>
> - cmd->eh_eflags = 0;
> -
> switch (res) {
> case TASK_IS_DONE:
> SAS_DPRINTK("%s: task 0x%p is done\n", __func__,
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index cec439c..e1ca3b8 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -189,7 +189,6 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host
> *shost)
> /*
> * Retry after abort failed, escalate to next level.
> */
> - scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;
> SCSI_LOG_ERROR_RECOVERY(3,
> scmd_printk(KERN_INFO, scmd,
> "previous abort failed\n"));
> @@ -933,6 +932,7 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct
> scsi_eh_save *ses,
> ses->result = scmd->result;
> ses->underflow = scmd->underflow;
> ses->prot_op = scmd->prot_op;
> + ses->eh_eflags = scmd->eh_eflags;
>
> scmd->prot_op = SCSI_PROT_NORMAL;
> scmd->eh_eflags = 0;
> @@ -996,6 +996,7 @@ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct
> scsi_eh_save *ses)
> scmd->result = ses->result;
> scmd->underflow = ses->underflow;
> scmd->prot_op = ses->prot_op;
> + scmd->eh_eflags = ses->eh_eflags;
> }
> EXPORT_SYMBOL(scsi_eh_restore_cmnd);
>
> @@ -1140,7 +1141,6 @@ static int scsi_eh_reset(struct scsi_cmnd *scmd)
> */
> void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
> {
> - scmd->eh_eflags = 0;
> list_move_tail(&scmd->eh_entry, done_q);
> }
> EXPORT_SYMBOL(scsi_eh_finish_cmd);
> diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
> index 98d366b..a25b328 100644
> --- a/include/scsi/scsi_eh.h
> +++ b/include/scsi/scsi_eh.h
> @@ -31,6 +31,7 @@ extern int scsi_get_sense_info_fld(const u8 * sense_buffer,
> int sb_len,
> struct scsi_eh_save {
> /* saved state */
> int result;
> + int eh_eflags;
> enum dma_data_direction data_direction;
> unsigned underflow;
> unsigned char cmd_len;
> --
> 1.8.5.6
>
So I think the code is good. The only thing I am missing is a bit of
reasoning why we want to escalate immediately after an already retried
command fails again. Anyway, would not require code-changes.
Reviewed-by: Benjamin Block <bbl...@linux.vnet.ibm.com>
Beste Grüße / Best regards,
- Benjamin Block
--
Linux on z Systems Development / IBM Systems & Technology Group
IBM Deutschland Research & Development GmbH
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