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scsi: scsi_debug: skip long delays when ndelay small

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A test program's runtime became impractically long since any non zero
ndelay (e.g. 1 nanosec) caused Start Stop Unit to delay over 8 magnitudes
greater than other commands. This patch skips long delays (on Start Stop
Unit and Synchronize Cache) if ndelay is less than or equal to 10
microsecs.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Douglas Gilbert 2018-07-12 13:35:42 -04:00 committed by Martin K. Petersen
parent 920447f138
commit 75aa3209c9
1 changed files with 6 additions and 4 deletions
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10
drivers/scsi/scsi_debug.c
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@ -5790,11 +5790,13 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
fini:
if (F_DELAY_OVERR & flags)
return schedule_resp(scp, devip, errsts, pfp, 0, 0);
else if ((sdebug_jdelay || sdebug_ndelay) && (flags & F_LONG_DELAY)) {
else if ((flags & F_LONG_DELAY) && (sdebug_jdelay > 0 ||
sdebug_ndelay > 10000)) {
/*
* If any delay is active, for F_SSU_DELAY want at least 1
* second and if sdebug_jdelay>0 want a long delay of that
* many seconds; for F_SYNC_DELAY want 1/20 of that.
* Skip long delays if ndelay <= 10 microseconds. Otherwise
* for Start Stop Unit (SSU) want at least 1 second delay and
* if sdebug_jdelay>1 want a long delay of that many seconds.
* For Synchronize Cache want 1/20 of SSU's delay.
*/
int jdelay = (sdebug_jdelay < 2) ? 1 : sdebug_jdelay;
int denom = (flags & F_SYNC_DELAY) ? 20 : 1;