drbd: cleanup: change "<= 0" to "== 0"

PATCH In review Dan Carpenter 3 participants 6 messages Aug 11, 2010 – Aug 24, 2010

Subsystems (3)

Block layer Kernel janitors DRBD driver

lore

Share & tools

lore

Dan Carpenter

author

2010-08-11 22:38 UTC #0 lore raw

PATCH 1/1 drbd: cleanup: change "<= 0" to "== 0"

dt is unsigned so it's never less than zero. We are calculating the elapsed time, and that's never less than zero (unless there is a bug or we invent time travel). The comparison here is just to guard against divide by zero bugs.

Signed-off-by Dan Carpenter <[email protected]>

drivers/block/drbd/drbd_proc.c +1 -1

index be3374b..4c0c4aa 100644
@@ -118,7 +118,7 @@ static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq)
 	/* mean speed since syncer started
 	 * we do account for PausedSync periods */
 	dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
-	if (dt <= 0)
+	if (dt = 0)
 		dt = 1;
 	db = mdev->rs_total - rs_left;
 	dbdt = Bit2KB(db/dt);

Jens Axboe

2010-08-23 10:34 UTC #1 lore raw

Quoted 12 lines · Dan Carpenter

dt is unsigned so it's never less than zero. We are calculating the elapsed time, and that's never less than zero (unless there is a bug or we invent time travel). The comparison here is just to guard against divide by zero bugs.
Signed-off-by Dan Carpenter <[email protected]>
drivers/block/drbd/drbd_proc.c +0 -0
index be3374b..4c0c4aa 100644

drivers/block/drbd/drbd_proc.c static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq) · line 124

Quoted 8 lines

drivers/block/drbd/drbd_proc.c +1 -1

@@ -118,7 +118,7 @@ static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq)
 	/* mean speed since syncer started
 	 * we do account for PausedSync periods */
 	dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
-	if (dt <= 0)
+	if (dt == 0)
 		dt = 1;
 	db = mdev->rs_total - rs_left;
 	dbdt = Bit2KB(db/dt);

Lars et al, I'll let you pick this up.

Signature · 1 line

Jens Axboe

Philipp Reisner

maintainer

2010-08-23 16:03 UTC #2 lore raw

Am Montag, 23. August 2010, um 12:34:29 schrieb Jens Axboe:

Quoted 24 lines · Dan Carpenter

Quoted 23 lines
dt is unsigned so it's never less than zero. We are calculating the elapsed time, and that's never less than zero (unless there is a bug or we invent time travel). The comparison here is just to guard against divide by zero bugs.
Signed-off-by Dan Carpenter <[email protected]>
(quoted diff) +0 -0
b/drivers/block/drbd/drbd_proc.c index be3374b..4c0c4aa 100644
drivers/block/drbd/drbd_proc.c +1 -1
@@ -118,7 +118,7 @@ static void drbd_syncer_progress(struct drbd_conf
 *mdev, struct seq_file *seq)
 
 	/* mean speed since syncer started
 
 	 * we do account for PausedSync periods */
 
 	dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
 
-	if (dt <= 0)
+	if (dt == 0)

Quoted 6 lines

drivers/block/drbd/drbd_proc.c static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq) · line 124
Quoted 4 lines
drivers/block/drbd/drbd_proc.c +0 -0
 		dt = 1;
 
 	db = mdev->rs_total - rs_left;
 	dbdt = Bit2KB(db/dt);
Lars et al, I'll let you pick this up.

Jens, we (LINBIT) feel responsible for picking this up. I work on that tomorrow.

Best,
Phil

Signature · 6 lines

: Dipl-Ing Philipp Reisner
: LINBIT | Your Way to High Availability
: Tel: +43-1-8178292-50, Fax: +43-1-8178292-82
: http://www.linbit.com

DRBD(R) and LINBIT(R) are registered trademarks of LINBIT, Austria.

Philipp Reisner

maintainer

2010-08-24 08:38 UTC #3 lore raw

In reply to Dan Carpenter

Am Donnerstag, 12. August 2010, um 00:38:45 schrieb Dan Carpenter:

Quoted 12 lines

dt is unsigned so it's never less than zero. We are calculating the elapsed time, and that's never less than zero (unless there is a bug or we invent time travel). The comparison here is just to guard against divide by zero bugs.
Signed-off-by Dan Carpenter <[email protected]>
(quoted diff) +0 -0
b/drivers/block/drbd/drbd_proc.c index be3374b..4c0c4aa 100644

drivers/block/drbd/drbd_proc.c static void drbd_syncer_progress(struct drbd_conf · line 124

Quoted 8 lines

drivers/block/drbd/drbd_proc.c +1 -1

@@ -118,7 +118,7 @@ static void drbd_syncer_progress(struct drbd_conf
 *mdev, struct seq_file *seq) /* mean speed since syncer started
 	 * we do account for PausedSync periods */
 	dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
-	if (dt <= 0)
+	if (dt == 0)
 		dt = 1;
 	db = mdev->rs_total - rs_left;
 	dbdt = Bit2KB(db/dt);

Hi Dan,

Please elaborate the improvement this patch brings. dt can actually get negative, on jiffie wrap. I see little value in displaying then a negative resync speed...

Best,
Phil

Signature · 6 lines

: Dipl-Ing Philipp Reisner
: LINBIT | Your Way to High Availability
: Tel: +43-1-8178292-50, Fax: +43-1-8178292-82
: http://www.linbit.com

DRBD(R) and LINBIT(R) are registered trademarks of LINBIT, Austria.

Jens Axboe

2010-08-24 08:41 UTC #4 lore raw

Quoted 24 lines · Philipp Reisner

Am Donnerstag, 12. August 2010, um 00:38:45 schrieb Dan Carpenter:
Quoted 12 lines
dt is unsigned so it's never less than zero. We are calculating the elapsed time, and that's never less than zero (unless there is a bug or we invent time travel). The comparison here is just to guard against divide by zero bugs.
Signed-off-by Dan Carpenter <[email protected]>
(quoted diff) +0 -0
b/drivers/block/drbd/drbd_proc.c index be3374b..4c0c4aa 100644
drivers/block/drbd/drbd_proc.c static void drbd_syncer_progress(struct drbd_conf · line 124
Quoted 8 lines
drivers/block/drbd/drbd_proc.c +1 -1
@@ -118,7 +118,7 @@ static void drbd_syncer_progress(struct drbd_conf
 *mdev, struct seq_file *seq) /* mean speed since syncer started
 	 * we do account for PausedSync periods */
 	dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
-	if (dt <= 0)
+	if (dt == 0)
 		dt = 1;
 	db = mdev->rs_total - rs_left;
 	dbdt = Bit2KB(db/dt);
Hi Dan,

Quoted 3 lines

Please elaborate the improvement this patch brings. dt can actually get negative, on jiffie wrap. I see little value in displaying then a negative resync speed...

Aren't all members unsigned long? If not, then you have another bug.

Signature · 1 line

Jens Axboe

Philipp Reisner

maintainer

2010-08-24 09:10 UTC #5 lore raw

Am Dienstag, 24. August 2010, um 10:41:31 schrieb Jens Axboe:

Quoted 30 lines · Philipp Reisner

Quoted 29 lines
Am Donnerstag, 12. August 2010, um 00:38:45 schrieb Dan Carpenter:
Quoted 21 lines
dt is unsigned so it's never less than zero. We are calculating the elapsed time, and that's never less than zero (unless there is a bug or we invent time travel). The comparison here is just to guard against divide by zero bugs.
Signed-off-by Dan Carpenter <[email protected]>
(quoted diff) +0 -0
b/drivers/block/drbd/drbd_proc.c index be3374b..4c0c4aa 100644
drivers/block/drbd/drbd_proc.c +1 -1
@@ -118,7 +118,7 @@ static void drbd_syncer_progress(struct drbd_conf
 *mdev, struct seq_file *seq) /* mean speed since syncer started
 
 	 * we do account for PausedSync periods */
 
 	dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
 
-	if (dt <= 0)
+	if (dt == 0)
drivers/block/drbd/drbd_proc.c static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq) · line 124
Quoted 4 lines
drivers/block/drbd/drbd_proc.c +0 -0
 		dt = 1;
 
 	db = mdev->rs_total - rs_left;
 	dbdt = Bit2KB(db/dt);
Hi Dan,

Quoted 6 lines

Quoted 3 lines
Please elaborate the improvement this patch brings. dt can actually get negative, on jiffie wrap. I see little value in displaying then a negative resync speed...
Aren't all members unsigned long? If not, then you have another bug.

Um, well that is right. Ok, patch goes in.

Best,
Phil

Signature · 6 lines

: Dipl-Ing Philipp Reisner
: LINBIT | Your Way to High Availability
: Tel: +43-1-8178292-50, Fax: +43-1-8178292-82
: http://www.linbit.com

DRBD(R) and LINBIT(R) are registered trademarks of LINBIT, Austria.