Bart, On 2/21/17 02:34, Bart Van Assche wrote: > On 02/16/2017 04:20 PM, Damien Le Moal wrote: >> Move the partial completion alignement check of mpt3sas to a generic >> implementation in sd_done so that the check ignores REQ_TYPE_FS >> requests with special payload size handling (REQ_OP_DISCARD, >> REQ_OP_WRITE_SAME, REQ_OP_ZONE_REPORT and REQ_OP_ZONE_RESET). > > Hello Damien, > > Since the resid adjustment code is skipped for REQ_OP_DISCARD and > REQ_OP_WRITE_SAME: does the mpt3sas firmware ensure that 'resid' is > properly aligned for these request types? Did I perhaps miss something? No, I do not think anything special is done for these commands in the driver (I did not see any code to that effect). But for discard, since the payload is one sector, it always should be aligned (or 0). So the actual value from the driver is ignored and overwritten in the switch-case code with the actual request size on success (not the payload size) and 0 on error. If anything, if the HW returned a non-0 resid, we should mark the command as failed. For write-same, it is basically the same. The payload is one page containing the sector range to discard (soon multiple ranges actually). If the commands succeeded, then clearly resid should be 0 and the value returned by the HW ignored. In case of a failed command, no matter what resid is, the discard is marked as entirely failed. Similarly to write-same, a success with a non-0 resid is non-sensical. So we could force the request as failed here in this case. Best regards. -- Damien Le Moal, Ph.D. Sr. Manager, System Software Research Group, Western Digital Corporation Damien.LeMoal@xxxxxxx (+81) 0466-98-3593 (ext. 513593) 1 kirihara-cho, Fujisawa, Kanagawa, 252-0888 Japan www.wdc.com, www.hgst.com
