On Thu, 2016-06-02 at 16:42 +0800, Wei Fang wrote:
> Update the new rules of ->host_failed.
>
> Signed-off-by: Wei Fang <fangwei1@xxxxxxxxxx>
Changes look fine, but I was wondering if we could also add a note
about the new concurrency rules:
> ---
> Documentation/scsi/scsi_eh.txt | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/Documentation/scsi/scsi_eh.txt
> b/Documentation/scsi/scsi_eh.txt
> index 8638f61..9702c78 100644
> --- a/Documentation/scsi/scsi_eh.txt
> +++ b/Documentation/scsi/scsi_eh.txt
> @@ -263,7 +263,6 @@ scmd->allowed.
>
> 3. scmd recovered
> ACTION: scsi_eh_finish_cmd() is invoked to EH-finish scmd
> - - shost->host_failed--
> - clear scmd->eh_eflags
> - scsi_setup_cmd_retry()
> - move from local eh_work_q to local eh_done_q
+ CONCURRENCY: at most one thread per separate eh_work_q to
+ keep queue manipulation lockless
And the same addition in
4. EH Completes
Probably
ACTION: scsi_eh_flush_done_q() retries scmds or notifies upper
layer of failure. May be called concurrently but must have
a no more than one thread per eh_work_q to manipulate the
queue locklessly
> @@ -276,6 +275,7 @@ scmd->allowed.
> - if retry is necessary, scmd is requeued using
> scsi_queue_insert()
> - otherwise, scsi_finish_command() is invoked for scmd
> + - zero shost->host_failed
> LOCKING: queue or finish function performs appropriate locking
>
>
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