This patch uses a cleaner method to convey the presence of the IMMED
cdb bit back to the generic delay code in the scsi_debug driver. The
previous method used a temporary mask over the SCSI result value
(a 32 bit integer soon to be restructured) that was not visible
outside this driver. It has still caused some confusion so a more
conventional method is now used: adding an extra flag to the
scsi_cmnd "host_scribble" area.
Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
---
This patch is designed to simplify part of the patchset titled:
"Rework SCSI results handling" that touched the scsi_debug driver.
This patch is against Martin's 4.18/scsi-queue branch. It will
probably break soon as that branch doesn't yet contain my
"scsi_debug: IMMED related delay adjustments" patch which touches
the same area. The technique being used should be clear.
drivers/scsi/scsi_debug.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 9ef5e3b810f6..65809f3d0d33 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -234,7 +234,7 @@ static const char *sdebug_version_date = "20180128";
#define F_INV_OP 0x200
#define F_FAKE_RW 0x400
#define F_M_ACCESS 0x800 /* media access */
-#define F_LONG_DELAY 0x1000
+#define F_LONG_DELAY 0x1000 /* IMMED bit on commands with this */
#define FF_RESPOND (F_RL_WLUN_OK | F_SKIP_UA | F_DELAY_OVERR)
#define FF_MEDIA_IO (F_M_ACCESS | F_FAKE_RW)
@@ -294,6 +294,7 @@ struct sdebug_queued_cmd {
unsigned int inj_dix:1;
unsigned int inj_short:1;
unsigned int inj_host_busy:1;
+ bool immed_shortens_delay;
};
struct sdebug_queue {
@@ -399,14 +400,6 @@ static const unsigned char opcode_ind_arr[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
-/*
- * The following "response" functions return the SCSI mid-level's 4 byte
- * tuple-in-an-int. To handle commands with an IMMED bit, for a faster
- * command completion, they can mask their return value with
- * SDEG_RES_IMMED_MASK .
- */
-#define SDEG_RES_IMMED_MASK 0x40000000
-
static int resp_inquiry(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_report_luns(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_requests(struct scsi_cmnd *, struct sdebug_dev_info *);
@@ -1607,6 +1600,8 @@ static int resp_start_stop(struct scsi_cmnd *scp,
{
unsigned char *cmd = scp->cmnd;
int power_cond, stop;
+ struct sdebug_queued_cmd *sqcp =
+ (struct sdebug_queued_cmd *)scp->host_scribble;
power_cond = (cmd[4] & 0xf0) >> 4;
if (power_cond) {
@@ -1615,7 +1610,8 @@ static int resp_start_stop(struct scsi_cmnd *scp,
}
stop = !(cmd[4] & 1);
atomic_xchg(&devip->stopped, stop);
- return (cmd[1] & 0x1) ? SDEG_RES_IMMED_MASK : 0; /* check IMMED bit */
+ sqcp->immed_shortens_delay = !!(cmd[1] & 0x1);
+ return 0;
}
static sector_t get_sdebug_capacity(void)
@@ -3586,6 +3582,8 @@ static int resp_sync_cache(struct scsi_cmnd *scp,
u64 lba;
u32 num_blocks;
u8 *cmd = scp->cmnd;
+ struct sdebug_queued_cmd *sqcp =
+ (struct sdebug_queued_cmd *)scp->host_scribble;
if (cmd[0] == SYNCHRONIZE_CACHE) { /* 10 byte cdb */
lba = get_unaligned_be32(cmd + 2);
@@ -3598,7 +3596,8 @@ static int resp_sync_cache(struct scsi_cmnd *scp,
mk_sense_buffer(scp, ILLEGAL_REQUEST, LBA_OUT_OF_RANGE, 0);
return check_condition_result;
}
- return (cmd[1] & 0x2) ? SDEG_RES_IMMED_MASK : 0; /* check IMMED bit */
+ sqcp->immed_shortens_delay = !!(cmd[1] & 0x2);
+ return 0;
}
#define RL_BUCKET_ELEMS 8
@@ -4399,12 +4398,12 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
}
cmnd->result = pfp != NULL ? pfp(cmnd, devip) : 0;
- if (cmnd->result & SDEG_RES_IMMED_MASK) {
+ if (sqcp->immed_shortens_delay) {
/*
- * This is the F_DELAY_OVERR case. No delay.
+ * IMMED bit set overrides F_LONG_DELAY.
*/
- cmnd->result &= ~SDEG_RES_IMMED_MASK;
- delta_jiff = ndelay = 0;
+ delta_jiff = 0;
+ ndelay = 0;
}
if (cmnd->result == 0 && scsi_result != 0)
cmnd->result = scsi_result;
@@ -4456,7 +4455,6 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
respond_in_thread: /* call back to mid-layer using invocation thread */
cmnd->result = pfp != NULL ? pfp(cmnd, devip) : 0;
- cmnd->result &= ~SDEG_RES_IMMED_MASK;
if (cmnd->result == 0 && scsi_result != 0)
cmnd->result = scsi_result;
cmnd->scsi_done(cmnd);
--
2.14.1
