FUJITA Tomonori wrote:
> The failure to map user-space pages leads to scsi command leak. It can
> happens mostly because of user-space daemon bugs (or OOM). This patch
> makes tgt just notify a LLD of the failure with sense when
> blk_rq_map_user() fails.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
> Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
> ---
> drivers/scsi/scsi_tgt_lib.c | 23 ++++++++++++++++++++---
> 1 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
> index dc8781a..c05dff9 100644
> --- a/drivers/scsi/scsi_tgt_lib.c
> +++ b/drivers/scsi/scsi_tgt_lib.c
> @@ -459,6 +459,16 @@ static struct request *tgt_cmd_hash_look
> return rq;
> }
>
> +static void scsi_tgt_build_sense(unsigned char *sense_buffer, unsigned char key,
> + unsigned char asc, unsigned char asq)
> +{
> + sense_buffer[0] = 0x70;
> + sense_buffer[2] = key;
> + sense_buffer[7] = 0xa;
> + sense_buffer[12] = asc;
> + sense_buffer[13] = asq;
> +}
> +
Tomo,
Perhaps you could add a memset(sense_buffer, 0, 18) before
those assignments and state that this is "fixed" sense
buffer format.
What about an option for descriptor sense format? With SAT now
a standard, we now have one more reason to support
descriptor format when required. The ATA PASS-THROUGH SCSI
commands in SAT use descriptor sense format to return
ATA registers.
<aside>
While on the subject of sense data, I note that the
ATA folks (t13.org) are proposing an "ATA REQUEST
SENSE" command to leverage of existing SCSI
sense_key, asc, ascq tuples.
Doug Gilbert
> int scsi_tgt_kspace_exec(int host_no, int result, u64 tag,
> unsigned long uaddr, u32 len, unsigned long sense_uaddr,
> u32 sense_len, u8 rw)
> @@ -514,9 +524,16 @@ int scsi_tgt_kspace_exec(int host_no, in
> if (len) {
> err = scsi_map_user_pages(rq->end_io_data, cmd, uaddr, len, rw);
> if (err) {
> - eprintk("%p %d\n", cmd, err);
> - err = -EAGAIN;
> - goto done;
> + /*
> + * user-space daemon bugs or OOM
> + * TODO: we can do better for OOM.
> + */
> + eprintk("cmd %p ret %d uaddr %lx len %d rw %d\n",
> + cmd, err, uaddr, len, rw);
> + cmd->result = SAM_STAT_CHECK_CONDITION;
> + memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
> + scsi_tgt_build_sense(cmd->sense_buffer,
> + HARDWARE_ERROR, 0, 0);
> }
> }
> err = scsi_tgt_transfer_response(cmd);
-
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