RE: [PATCH 1/1] Drivers: scsi: storvsc: Account for in-transitpackets in the RESET path

[KY Srinivasan]

> -----Original Message-----
> From: K. Y. Srinivasan [mailto:kys@xxxxxxxxxxxxx]
> Sent: Tuesday, October 02, 2012 2:04 PM
> To: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; ohering@xxxxxxxx; jbottomley@xxxxxxxxxxxxx;
> hch@xxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx
> Cc: KY Srinivasan; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH 1/1] Drivers: scsi: storvsc: Account for in-transit packets in the
> RESET path
> 
> Properly account for I/O in transit before returning from the RESET call.
> In the absense of this patch, we could have a situation where the host may
> respond to a command that was issued prior to the issuance of the RESET
> command at some arbitrary time after responding to the RESET command.
> Currently, the host does not do anything with the RESET command.
> 
> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
>  drivers/scsi/storvsc_drv.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 528d52b..0144078 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1221,7 +1221,12 @@ static int storvsc_host_reset_handler(struct scsi_cmnd
> *scmnd)
>  	/*
>  	 * At this point, all outstanding requests in the adapter
>  	 * should have been flushed out and return to us
> +	 * There is a potential race here where the host may be in
> +	 * the process of responding when we return from here.
> +	 * Just wait for all in-transit packets to be accounted for
> +	 * before we return from here.
>  	 */
> +	storvsc_wait_to_drain(stor_device);
> 
>  	return SUCCESS;
>  }
> --
> 1.7.4.1

James,

This patch is critical for running Linux based workloads on our Cloud infrastructure - Azure.
Please let me know if there are any issues.

Regards,

K. Y



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