From f1a0743bc0e7a30c032b1eb78f6a2b0f805b4597 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 6 Oct 2009 14:07:57 -0400 Subject: USB: storage: When a device returns no sense data, call it a Hardware Error This patch (as1294) fixes a problem that has plagued users for several kernel releases. Some USB mass-storage devices don't return any sense data when they encounter certain kinds of errors. The SCSI layer interprets this to mean that the operation should be retried, and the same thing happens -- over and over again with no limit. In some circumstances (such as when a bus reset occurs) that is the right thing to do, but not here. The patch checks for this condition (a transport failure with no sense data) and changes the result code to DID_ERROR and the sense code to Hardware Error. This does get only a limited number of retries, and so the command will fail relatively quickly instead of getting stuck in an infinite loop. This fixes a large part of Bugzilla #14118. Signed-off-by: Alan Stern Tested-by: Mantas Mikulenas CC: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/storage/transport.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c index e20dc525d177..3a4fb023af72 100644 --- a/drivers/usb/storage/transport.c +++ b/drivers/usb/storage/transport.c @@ -768,17 +768,32 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us) /* set the result so the higher layers expect this data */ srb->result = SAM_STAT_CHECK_CONDITION; - /* If things are really okay, then let's show that. Zero - * out the sense buffer so the higher layers won't realize - * we did an unsolicited auto-sense. */ - if (result == USB_STOR_TRANSPORT_GOOD && - /* Filemark 0, ignore EOM, ILI 0, no sense */ + /* We often get empty sense data. This could indicate that + * everything worked or that there was an unspecified + * problem. We have to decide which. + */ + if ( /* Filemark 0, ignore EOM, ILI 0, no sense */ (srb->sense_buffer[2] & 0xaf) == 0 && /* No ASC or ASCQ */ srb->sense_buffer[12] == 0 && srb->sense_buffer[13] == 0) { - srb->result = SAM_STAT_GOOD; - srb->sense_buffer[0] = 0x0; + + /* If things are really okay, then let's show that. + * Zero out the sense buffer so the higher layers + * won't realize we did an unsolicited auto-sense. + */ + if (result == USB_STOR_TRANSPORT_GOOD) { + srb->result = SAM_STAT_GOOD; + srb->sense_buffer[0] = 0x0; + + /* If there was a problem, report an unspecified + * hardware error to prevent the higher layers from + * entering an infinite retry loop. + */ + } else { + srb->result = DID_ERROR << 16; + srb->sense_buffer[2] = HARDWARE_ERROR; + } } } -- cgit v1.2.3