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Commit 71982a40 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
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block: include empty disks in /proc/diskstats 



/proc/diskstats used to show stats for all disks whether they're
zero-sized or not and their non-zero partitions.  Commit
074a7aca accidentally changed the
behavior such that it doesn't print out zero sized disks.  This patch
implements DISK_PITER_INCL_EMPTY_PART0 flag to partition iterator and
uses it in diskstats_show() such that empty part0 is shown in
/proc/diskstats.

Reported and bisectd by Dianel Collins.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarDaniel Collins <solemnwarning@solemnwarning.no-ip.org>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent a9e9dc24

block/genhd.c

+8 −4
Original line number Diff line number Diff line
@@ -98,7 +98,7 @@ void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, 


	if (flags & DISK_PITER_REVERSE)

		piter->idx = ptbl->len - 1;

	else if (flags & DISK_PITER_INCL_PART0)

	else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))

		piter->idx = 0;

	else

		piter->idx = 1;
@@ -134,7 +134,8 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) 
	/* determine iteration parameters */

	if (piter->flags & DISK_PITER_REVERSE) {

		inc = -1;

		if (piter->flags & DISK_PITER_INCL_PART0)

		if (piter->flags & (DISK_PITER_INCL_PART0 |

				    DISK_PITER_INCL_EMPTY_PART0))

			end = -1;

		else

			end = 0;
@@ -150,7 +151,10 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) 
		part = rcu_dereference(ptbl->part[piter->idx]);

		if (!part)

			continue;

		if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects)

		if (!part->nr_sects &&

		    !(piter->flags & DISK_PITER_INCL_EMPTY) &&

		    !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&

		      piter->idx == 0))

			continue;



		get_device(part_to_dev(part));
@@ -1011,7 +1015,7 @@ static int diskstats_show(struct seq_file *seqf, void *v) 
				"\n\n");

	*/

 

	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_PART0);

	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);

	while ((hd = disk_part_iter_next(&piter))) {

		cpu = part_stat_lock();

		part_round_stats(cpu, hd);

include/linux/genhd.h

+1 −0
Original line number Diff line number Diff line
@@ -214,6 +214,7 @@ static inline void disk_put_part(struct hd_struct *part) 
#define DISK_PITER_REVERSE	(1 << 0) /* iterate in the reverse direction */

#define DISK_PITER_INCL_EMPTY	(1 << 1) /* include 0-sized parts */

#define DISK_PITER_INCL_PART0	(1 << 2) /* include partition 0 */

#define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */



struct disk_part_iter {

	struct gendisk		*disk;