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Date: Sat, 17 Mar 2012 19:55:40 +0100 From: Douglas Gilbert <dgilbert@...erlog.com> To: Jeff Garzik <jeff@...zik.org> CC: "K. Y. Srinivasan" <kys@...rosoft.com>, gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org, devel@...uxdriverproject.org, virtualization@...ts.osdl.org, ohering@...e.com, jbottomley@...allels.com, hch@...radead.org, linux-scsi@...r.kernel.org Subject: Re: [PATCH 2/2] Drivers: scsi: storvsc: Don't pass ATA_16 command to the host On 12-03-17 04:04 PM, Jeff Garzik wrote: > On 03/16/2012 04:24 PM, K. Y. Srinivasan wrote: >> The current Windows hosts don't handle the ATA_16 command and furthermore >> return a generic error code after filtering the command on the host side. >> For now filter the command on the guest side until the host is modified to >> properly handle unsupported commands. >> >> Signed-off-by: K. Y. Srinivasan<kys@...rosoft.com> >> Reviewed-by: Haiyang Zhang<haiyangz@...rosoft.com> >> --- >> drivers/scsi/storvsc_drv.c | 9 +++++++++ >> 1 files changed, 9 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c >> index 8b967c9..783bab8 100644 >> --- a/drivers/scsi/storvsc_drv.c >> +++ b/drivers/scsi/storvsc_drv.c >> @@ -1229,8 +1229,17 @@ static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd) >> /* >> * smartd sends this command and the host does not handle >> * this. So, don't send it. >> + * The current Windows hosts implement a subset of scsi commands >> + * and for the commands that are not implemented, the host filters >> + * them and returns a generic failure SRB status. I have been in >> + * discussions with the Windows team to return the appropriate SRB >> + * status code for unsupported scsi commands and while they have >> + * agreed to implement this, it is not clear when this change will be >> + * available. Consequently, filtering the command before submitting it >> + * to the host is a resonable interim solution. >> */ >> case SET_WINDOW: >> + case ATA_16: >> scmnd->result = ILLEGAL_REQUEST<< 16; >> allowed = false; > > It would be even nicer to fill out a nice SCSI status for this. For an illegal > request such as this, the libata SCSI simulator (drivers/ata/libata-scsi.c) uses > a more complete sense buffer setup, > > static void ata_scsi_set_sense(struct scsi_cmnd *cmd, u8 sk, > u8 asc, u8 ascq) > { > cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION; > > scsi_build_sense_buffer(0, cmd->sense_buffer, sk, asc, ascq); > } > > and calls this function for invalid/unknown/unsupported command ops thusly, > > ata_scsi_set_sense(cmd, ILLEGAL_REQUEST, 0x20, 0x0); > /* "Invalid command operation code" */ > > Supplying asc/ascq provides additional information that may be useful in > determining whether or not to retry, provide better error diagnostics, etc. > > The asc/ascq values are found in the SCSI standards documents. Jeff, I agree with your suggestion and would point out that the originally proposed: scmnd->result = ILLEGAL_REQUEST<< 16; is just plain wrong. result[23:16] is a Linux invented host byte code (they typically start with "DID_") while ILLEGAL_REQUEST is a SCSI sense key. Doug Gilbert -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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