Hi, There was a recent commit in mainline for the scsi devices which do not respond properly to medium access command:
commit 18a4d0a22ed6c54b67af7718c305cd010f09ddf8 [SCSI] Handle disk devices which can not process medium access commands We have experienced several devices which fail in a fashion we do not currently handle gracefully in SCSI. After a failure these devices will respond to the SCSI primary command set (INQUIRY, TEST UNIT READY, etc.) but any command accessing the storage medium will time out. I came across a USB drive which showed similar problem and what I see is usb storage is still not able to cope with such devices properly. The control flow downwards is like: scsi_times_out --> Setting cmd->result as DID_TIME_OUT scsi_error_handler scsi_unjam_host scsi_eh_abort_cmds command_abort (sets US_FLIDX_TIMED_OUT for us->dflags calls stop_transport, and waits for) usb_stor_control_thread (which is waiting for transport call to return inside usb_stor_invoke_transport) both usb_stor_control_thread and usb_stor_invoke_transport check for us->dflags timed_out bit and set the result as DID_ABORT and signal completion for command_abort to complete ...... sd_eh_action checks for cmd->result and finds out that it's DID_ABORT rather than DID_TIME_OUT. This patch updates the command result to be TIME_OUT explicitly before returning from command_abort in scsiglue.c. I would like to know if this patch can work out for such USB Storage devices? What would be the better way to do the same? Regards, Vishal Annapurve
From: Vishal Annapurve <vannapu...@nvidia.com> Subject: [PATCH] usb-storage: Changing the command result This change updates the returned result to scsi layer to use DID_TIMEOUT flag as a result status rather than DID_ABORT for commands aborted due to timeout. Signed-off-by: Vishal Annapurve <vannapu...@nvidia.com> --- drivers/usb/storage/scsiglue.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c index a74e9d8..e7b532e 100644 --- a/drivers/usb/storage/scsiglue.c +++ b/drivers/usb/storage/scsiglue.c @@ -353,6 +353,15 @@ static int command_abort(struct scsi_cmnd *srb) /* Wait for the aborted command to finish */ wait_for_completion(&us->notify); + /* Given that this bit would be only set in case of timedout + * command, we can return with DID_TIME_OUT, as scsi layer needs + * to use this result rather than DID_ABORT. + * This is a WR to avoid removing DID_ABORT altogether + * and before the final control goes to scsi layer change the + * result to be timedout. + */ + us->srb->result = DID_TIME_OUT << 16; + return SUCCESS; } -- 1.8.4