From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ewan Milne Subject: Re: [PATCH] scsi: retry MODE SENSE on unit attention Date: Fri, 12 Jun 2015 10:08:25 -0400 Message-ID: <1434118105.22842.8.camel@localhost.localdomain> References: <1434020506-41897-1-git-send-email-hare@suse.de> <1434035231.27387.111.camel@localhost.localdomain> <557A7BD3.7040607@suse.de> Reply-To: emilne@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:40175 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752713AbbFLOI1 (ORCPT ); Fri, 12 Jun 2015 10:08:27 -0400 In-Reply-To: <557A7BD3.7040607@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: James Bottomley , linux-scsi@vger.kernel.org, Christoph Hellwig , Nic Bellinger On Fri, 2015-06-12 at 08:27 +0200, Hannes Reinecke wrote: > On 06/11/2015 05:07 PM, Ewan Milne wrote: > > On Thu, 2015-06-11 at 13:01 +0200, Hannes Reinecke wrote: > >> The 'sd' driver is calling scsi_mode_sense() to figure out > >> internal details. But scsi_mode_sense() never checks for > >> any pending unit attentions, so we're getting annoying error > >> messages like: > >> > >> MODE SENSE: unimplemented page/subpage: 0x00/0x00 > >> > >> and a possible wrong decision for device cache handling. > >> > >> Signed-off-by: Hannes Reinecke > >> --- > >> drivers/scsi/scsi_lib.c | 7 ++++++- > >> 1 file changed, 6 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > >> index 2428d96..d7915c8 100644 > >> --- a/drivers/scsi/scsi_lib.c > >> +++ b/drivers/scsi/scsi_lib.c > >> @@ -2423,7 +2423,7 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, > >> unsigned char cmd[12]; > >> int use_10_for_ms; > >> int header_length; > >> - int result; > >> + int result, retry_count = retries; > >> struct scsi_sense_hdr my_sshdr; > >> > >> memset(data, 0, sizeof(*data)); > >> @@ -2502,6 +2502,11 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, > >> data->block_descriptor_length = buffer[3]; > >> } > >> data->header_length = header_length; > >> + } else if ((status_byte(result) == CHECK_CONDITION) && > >> + scsi_sense_valid(sshdr) && > >> + sshdr->sense_key == UNIT_ATTENTION && retry_count) { > >> + retry_count--; > >> + goto retry; > >> } > >> > >> return result; > > > > Great, but shouldn't we be doing this more generally? What about > > scsi_mode_select()? > > > I haven't seen any issues with scsi_mode_select() as of now, so I > didn't do anything about this :-) > > > (And, with the number of status changes that can get reported by > > UAs, we might want to think about increasing the retry count on > > these commands up from 3 at some point.) > > > Hmm. _Actually_, we're not getting _more_ UAs (neither the number > nor the situation at which UAs are being send has changed). > It's just that we're trying to _use_ UAs so these things pop up. > But yeah, raising the number or retries to eg 5 is probably a good idea. Yeah, or maybe add a time limit to we don't drag out the boot time. We can do this later, though, I'm fine with your patch as it is. > > > Reviewed-by: Ewan D. Milne > > > Cheers, > > Hannes