Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
Enhanced partition statistics: documentation update
Enhanced partition statistics: remove old partition statistics
Enhanced partition statistics: procfs
Enhanced partition statistics: sysfs
Enhanced partition statistics: aoe fix
Enhanced partition statistics: update partition statitics
Enhanced partition statistics: core statistics
block: fixup rq_init() a bit

Manually fixed conflict in drivers/block/aoe/aoecmd.c due to statistics
support.

Documentation/ABI/testing/procfs-diskstats

···
+What:		/proc/diskstats
+Date:		February 2008
+Contact:	Jerome Marchand <[e-mail]>
+Description:
+		The /proc/diskstats file displays the I/O statistics
+		of block devices. Each line contains the following 14
+		fields:
+		 1 - major number
+		 2 - minor mumber
+		 3 - device name
+		 4 - reads completed succesfully
+		 5 - reads merged
+		 6 - sectors read
+		 7 - time spent reading (ms)
+		 8 - writes completed
+		 9 - writes merged
+		10 - sectors written
+		11 - time spent writing (ms)
+		12 - I/Os currently in progress
+		13 - time spent doing I/Os (ms)
+		14 - weighted time spent doing I/Os (ms)
+		For more details refer to Documentation/iostats.txt

Documentation/ABI/testing/sysfs-block

···
+What:		/sys/block/<disk>/stat
+Date:		February 2008
+Contact:	Jerome Marchand <[e-mail]>
+Description:
+		The /sys/block/<disk>/stat files displays the I/O
+		statistics of disk <disk>. They contain 11 fields:
+		 1 - reads completed succesfully
+		 2 - reads merged
+		 3 - sectors read
+		 4 - time spent reading (ms)
+		 5 - writes completed
+		 6 - writes merged
+		 7 - sectors written
+		 8 - time spent writing (ms)
+		 9 - I/Os currently in progress
+		10 - time spent doing I/Os (ms)
+		11 - weighted time spent doing I/Os (ms)
+		For more details refer Documentation/iostats.txt
+
+
+What:		/sys/block/<disk>/<part>/stat
+Date:		February 2008
+Contact:	Jerome Marchand <[e-mail]>
+Description:
+		The /sys/block/<disk>/<part>/stat files display the
+		I/O statistics of partition <part>. The format is the
+		same as the above-written /sys/block/<disk>/stat
+		format.

Documentation/iostats.txt

···
 Each set of stats only applies to the indicated device; if you want
 system-wide stats you'll have to find all the devices and sum them all up.
 
-Field  1 -- # of reads issued
+Field  1 -- # of reads completed
     This is the total number of reads completed successfully.
 Field  2 -- # of reads merged, field 6 -- # of writes merged
     Reads and writes which are adjacent to each other may be merged for
···
 words, the number of reads for partitions is counted slightly before time
 of queuing for partitions, and at completion for whole disks.  This is
 a subtle distinction that is probably uninteresting for most cases.
+
+More significant is the error induced by counting the numbers of
+reads/writes before merges for partitions and after for disks. Since a
+typical workload usually contains a lot of successive and adjacent requests,
+the number of reads/writes issued can be several times higher than the
+number of reads/writes completed.
+
+In 2.6.25, the full statistic set is again available for partitions and
+disk and partition statistics are consistent again. Since we still don't
+keep record of the partition-relative address, an operation is attributed to
+the partition which contains the first sector of the request after the
+eventual merges. As requests can be merged across partition, this could lead
+to some (probably insignificant) innacuracy.
 
 Additional notes
 ----------------

block/blk-core.c

···
 		return;
 
 	if (!new_io) {
-		__disk_stat_inc(rq->rq_disk, merges[rw]);
+		__all_stat_inc(rq->rq_disk, merges[rw], rq->sector);
 	} else {
+		struct hd_struct *part = get_part(rq->rq_disk, rq->sector);
 		disk_round_stats(rq->rq_disk);
 		rq->rq_disk->in_flight++;
+		if (part) {
+			part_round_stats(part);
+			part->in_flight++;
+		}
 	}
 }
 
···
 }
 EXPORT_SYMBOL(blk_get_backing_dev_info);
 
+/*
+ * We can't just memset() the structure, since the allocation path
+ * already stored some information in the request.
+ */
 void rq_init(struct request_queue *q, struct request *rq)
 {
 	INIT_LIST_HEAD(&rq->queuelist);
 	INIT_LIST_HEAD(&rq->donelist);
-
-	rq->errors = 0;
+	rq->q = q;
+	rq->sector = rq->hard_sector = (sector_t) -1;
+	rq->nr_sectors = rq->hard_nr_sectors = 0;
+	rq->current_nr_sectors = rq->hard_cur_sectors = 0;
 	rq->bio = rq->biotail = NULL;
 	INIT_HLIST_NODE(&rq->hash);
 	RB_CLEAR_NODE(&rq->rb_node);
-	rq->ioprio = 0;
-	rq->buffer = NULL;
-	rq->ref_count = 1;
-	rq->q = q;
-	rq->special = NULL;
-	rq->data_len = 0;
-	rq->data = NULL;
+	rq->rq_disk = NULL;
 	rq->nr_phys_segments = 0;
+	rq->nr_hw_segments = 0;
+	rq->ioprio = 0;
+	rq->special = NULL;
+	rq->buffer = NULL;
+	rq->tag = -1;
+	rq->errors = 0;
+	rq->ref_count = 1;
+	rq->cmd_len = 0;
+	memset(rq->cmd, 0, sizeof(rq->cmd));
+	rq->data_len = 0;
+	rq->sense_len = 0;
+	rq->data = NULL;
 	rq->sense = NULL;
 	rq->end_io = NULL;
 	rq->end_io_data = NULL;
-	rq->completion_data = NULL;
 	rq->next_rq = NULL;
 }
 
···
 }
 EXPORT_SYMBOL_GPL(disk_round_stats);
 
+void part_round_stats(struct hd_struct *part)
+{
+	unsigned long now = jiffies;
+
+	if (now == part->stamp)
+		return;
+
+	if (part->in_flight) {
+		__part_stat_add(part, time_in_queue,
+				part->in_flight * (now - part->stamp));
+		__part_stat_add(part, io_ticks, (now - part->stamp));
+	}
+	part->stamp = now;
+}
+
 /*
  * queue lock must be held
  */
···
 
 	if (bio_sectors(bio) && bdev != bdev->bd_contains) {
 		struct hd_struct *p = bdev->bd_part;
-		const int rw = bio_data_dir(bio);
-
-		p->sectors[rw] += bio_sectors(bio);
-		p->ios[rw]++;
 
 		bio->bi_sector += p->start_sect;
 		bio->bi_bdev = bdev->bd_contains;
···
 	if (blk_fs_request(req) && req->rq_disk) {
 		const int rw = rq_data_dir(req);
 
-		disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
+		all_stat_add(req->rq_disk, sectors[rw],
+			     nr_bytes >> 9, req->sector);
 	}
 
 	total_bytes = bio_nbytes = 0;
···
 	if (disk && blk_fs_request(req) && req != &req->q->bar_rq) {
 		unsigned long duration = jiffies - req->start_time;
 		const int rw = rq_data_dir(req);
+		struct hd_struct *part = get_part(disk, req->sector);
 
-		__disk_stat_inc(disk, ios[rw]);
-		__disk_stat_add(disk, ticks[rw], duration);
+		__all_stat_inc(disk, ios[rw], req->sector);
+		__all_stat_add(disk, ticks[rw], duration, req->sector);
 		disk_round_stats(disk);
 		disk->in_flight--;
+		if (part) {
+			part_round_stats(part);
+			part->in_flight--;
+		}
 	}
 
 	if (req->end_io)

block/blk-merge.c

···
 	elv_merge_requests(q, req, next);
 
 	if (req->rq_disk) {
+		struct hd_struct *part
+			= get_part(req->rq_disk, req->sector);
 		disk_round_stats(req->rq_disk);
 		req->rq_disk->in_flight--;
+		if (part) {
+			part_round_stats(part);
+			part->in_flight--;
+		}
 	}
 
 	req->ioprio = ioprio_best(req->ioprio, next->ioprio);

block/genhd.c

···
 	for (n = 0; n < gp->minors - 1; n++) {
 		struct hd_struct *hd = gp->part[n];
 
-		if (hd && hd->nr_sects)
-			seq_printf(s, "%4d %4d %s %u %u %u %u\n",
-				gp->major, n + gp->first_minor + 1,
-				disk_name(gp, n + 1, buf),
-				hd->ios[0], hd->sectors[0],
-				hd->ios[1], hd->sectors[1]);
+		if (!hd || !hd->nr_sects)
+			continue;
+
+		preempt_disable();
+		part_round_stats(hd);
+		preempt_enable();
+		seq_printf(s, "%4d %4d %s %lu %lu %llu "
+			   "%u %lu %lu %llu %u %u %u %u\n",
+			   gp->major, n + gp->first_minor + 1,
+			   disk_name(gp, n + 1, buf),
+			   part_stat_read(hd, ios[0]),
+			   part_stat_read(hd, merges[0]),
+			   (unsigned long long)part_stat_read(hd, sectors[0]),
+			   jiffies_to_msecs(part_stat_read(hd, ticks[0])),
+			   part_stat_read(hd, ios[1]),
+			   part_stat_read(hd, merges[1]),
+			   (unsigned long long)part_stat_read(hd, sectors[1]),
+			   jiffies_to_msecs(part_stat_read(hd, ticks[1])),
+			   hd->in_flight,
+			   jiffies_to_msecs(part_stat_read(hd, io_ticks)),
+			   jiffies_to_msecs(part_stat_read(hd, time_in_queue))
+			);
 	}
  
 	return 0;

drivers/block/aoe/aoecmd.c

···
 }
 
 static inline void
-diskstats(struct gendisk *disk, struct bio *bio, ulong duration)
+diskstats(struct gendisk *disk, struct bio *bio, ulong duration, sector_t sector)
 {
 	unsigned long n_sect = bio->bi_size >> 9;
 	const int rw = bio_data_dir(bio);
 
-	disk_stat_inc(disk, ios[rw]);
-	disk_stat_add(disk, ticks[rw], duration);
-	disk_stat_add(disk, sectors[rw], n_sect);
-	disk_stat_add(disk, io_ticks, duration);
+	all_stat_inc(disk, ios[rw], sector);
+	all_stat_add(disk, ticks[rw], duration, sector);
+	all_stat_add(disk, sectors[rw], n_sect, sector);
+	all_stat_add(disk, io_ticks, duration, sector);
 }
 
 void
···
 	}
 
 	if (buf && --buf->nframesout == 0 && buf->resid == 0) {
-		diskstats(d->gd, buf->bio, jiffies - buf->stime);
+		diskstats(d->gd, buf->bio, jiffies - buf->stime, buf->sector);
 		n = (buf->flags & BUFFL_FAIL) ? -EIO : 0;
 		bio_endio(buf->bio, n);
 		mempool_free(buf, d->bufpool);

fs/partitions/check.c

···
 #include <linux/fs.h>
 #include <linux/kmod.h>
 #include <linux/ctype.h>
+#include <linux/genhd.h>
 
 #include "check.h"
 
···
 {
 	struct hd_struct *p = dev_to_part(dev);
 
-	return sprintf(buf, "%8u %8llu %8u %8llu\n",
-		       p->ios[0], (unsigned long long)p->sectors[0],
-		       p->ios[1], (unsigned long long)p->sectors[1]);
+	preempt_disable();
+	part_round_stats(p);
+	preempt_enable();
+	return sprintf(buf,
+		"%8lu %8lu %8llu %8u "
+		"%8lu %8lu %8llu %8u "
+		"%8u %8u %8u"
+		"\n",
+		part_stat_read(p, ios[READ]),
+		part_stat_read(p, merges[READ]),
+		(unsigned long long)part_stat_read(p, sectors[READ]),
+		jiffies_to_msecs(part_stat_read(p, ticks[READ])),
+		part_stat_read(p, ios[WRITE]),
+		part_stat_read(p, merges[WRITE]),
+		(unsigned long long)part_stat_read(p, sectors[WRITE]),
+		jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
+		p->in_flight,
+		jiffies_to_msecs(part_stat_read(p, io_ticks)),
+		jiffies_to_msecs(part_stat_read(p, time_in_queue)));
 }
 
 #ifdef CONFIG_FAIL_MAKE_REQUEST
···
 static void part_release(struct device *dev)
 {
 	struct hd_struct *p = dev_to_part(dev);
+	free_part_stats(p);
 	kfree(p);
 }
 
···
 	disk->part[part-1] = NULL;
 	p->start_sect = 0;
 	p->nr_sects = 0;
-	p->ios[0] = p->ios[1] = 0;
-	p->sectors[0] = p->sectors[1] = 0;
+	part_stat_set_all(p, 0);
 	kobject_put(p->holder_dir);
 	device_del(&p->dev);
 	put_device(&p->dev);
···
 	if (!p)
 		return;
 
+	if (!init_part_stats(p)) {
+		kfree(p);
+		return;
+	}
 	p->start_sect = start;
 	p->nr_sects = len;
 	p->partno = part;

include/linux/blkdev.h

···
 #define BLK_MAX_CDB	16
 
 /*
- * try to put the fields that are referenced together in the same cacheline
+ * try to put the fields that are referenced together in the same cacheline.
+ * if you modify this structure, be sure to check block/blk-core.c:rq_init()
+ * as well!
  */
 struct request {
 	struct list_head queuelist;

include/linux/genhd.h

···
 	__le32 nr_sects;		/* nr of sectors in partition */
 } __attribute__((packed));
 
+struct disk_stats {
+	unsigned long sectors[2];	/* READs and WRITEs */
+	unsigned long ios[2];
+	unsigned long merges[2];
+	unsigned long ticks[2];
+	unsigned long io_ticks;
+	unsigned long time_in_queue;
+};
+	
 struct hd_struct {
 	sector_t start_sect;
 	sector_t nr_sects;
 	struct device dev;
 	struct kobject *holder_dir;
-	unsigned ios[2], sectors[2];	/* READs and WRITEs */
 	int policy, partno;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	int make_it_fail;
+#endif
+	unsigned long stamp;
+	int in_flight;
+#ifdef	CONFIG_SMP
+	struct disk_stats *dkstats;
+#else
+	struct disk_stats dkstats;
 #endif
 };
 
···
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	32
 #define GENHD_FL_FAIL				64
 
-struct disk_stats {
-	unsigned long sectors[2];	/* READs and WRITEs */
-	unsigned long ios[2];
-	unsigned long merges[2];
-	unsigned long ticks[2];
-	unsigned long io_ticks;
-	unsigned long time_in_queue;
-};
-	
+
 struct gendisk {
 	int major;			/* major number of driver */
 	int first_minor;
···
  * The __ variants should only be called in critical sections. The full
  * variants disable/enable preemption.
  */
+static inline struct hd_struct *get_part(struct gendisk *gendiskp,
+					 sector_t sector)
+{
+	struct hd_struct *part;
+	int i;
+	for (i = 0; i < gendiskp->minors - 1; i++) {
+		part = gendiskp->part[i];
+		if (part && part->start_sect <= sector
+		    && sector < part->start_sect + part->nr_sects)
+			return part;
+	}
+	return NULL;
+}
+
 #ifdef	CONFIG_SMP
 #define __disk_stat_add(gendiskp, field, addnd) 	\
 	(per_cpu_ptr(gendiskp->dkstats, smp_processor_id())->field += addnd)
···
 		memset(per_cpu_ptr(gendiskp->dkstats, i), value,
 				sizeof (struct disk_stats));
 }		
+
+#define __part_stat_add(part, field, addnd)				\
+	(per_cpu_ptr(part->dkstats, smp_processor_id())->field += addnd)
+
+#define __all_stat_add(gendiskp, field, addnd, sector)		\
+({								\
+	struct hd_struct *part = get_part(gendiskp, sector);	\
+	if (part)						\
+		__part_stat_add(part, field, addnd);		\
+	__disk_stat_add(gendiskp, field, addnd);		\
+})
+
+#define part_stat_read(part, field)					\
+({									\
+	typeof(part->dkstats->field) res = 0;				\
+	int i;								\
+	for_each_possible_cpu(i)					\
+		res += per_cpu_ptr(part->dkstats, i)->field;		\
+	res;								\
+})
+
+static inline void part_stat_set_all(struct hd_struct *part, int value)	{
+	int i;
+	for_each_possible_cpu(i)
+		memset(per_cpu_ptr(part->dkstats, i), value,
+		       sizeof(struct disk_stats));
+}
 				
 #else
 #define __disk_stat_add(gendiskp, field, addnd) \
 				(gendiskp->dkstats.field += addnd)
 #define disk_stat_read(gendiskp, field)	(gendiskp->dkstats.field)
 
-static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)	{
+static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)
+{
 	memset(&gendiskp->dkstats, value, sizeof (struct disk_stats));
 }
+
+#define __part_stat_add(part, field, addnd) \
+	(part->dkstats.field += addnd)
+
+#define __all_stat_add(gendiskp, field, addnd, sector)		\
+({								\
+	struct hd_struct *part = get_part(gendiskp, sector);	\
+	if (part)						\
+		part->dkstats.field += addnd;			\
+	__disk_stat_add(gendiskp, field, addnd);		\
+})
+
+#define part_stat_read(part, field)	(part->dkstats.field)
+
+static inline void part_stat_set_all(struct hd_struct *part, int value)
+{
+	memset(&part->dkstats, value, sizeof(struct disk_stats));
+}
+
 #endif
 
 #define disk_stat_add(gendiskp, field, addnd)			\
···
 #define disk_stat_sub(gendiskp, field, subnd) \
 		disk_stat_add(gendiskp, field, -subnd)
 
+#define part_stat_add(gendiskp, field, addnd)		\
+	do {						\
+		preempt_disable();			\
+		__part_stat_add(gendiskp, field, addnd);\
+		preempt_enable();			\
+	} while (0)
+
+#define __part_stat_dec(gendiskp, field) __part_stat_add(gendiskp, field, -1)
+#define part_stat_dec(gendiskp, field) part_stat_add(gendiskp, field, -1)
+
+#define __part_stat_inc(gendiskp, field) __part_stat_add(gendiskp, field, 1)
+#define part_stat_inc(gendiskp, field) part_stat_add(gendiskp, field, 1)
+
+#define __part_stat_sub(gendiskp, field, subnd) \
+		__part_stat_add(gendiskp, field, -subnd)
+#define part_stat_sub(gendiskp, field, subnd) \
+		part_stat_add(gendiskp, field, -subnd)
+
+#define all_stat_add(gendiskp, field, addnd, sector)		\
+	do {							\
+		preempt_disable();				\
+		__all_stat_add(gendiskp, field, addnd, sector);	\
+		preempt_enable();				\
+	} while (0)
+
+#define __all_stat_dec(gendiskp, field, sector) \
+		__all_stat_add(gendiskp, field, -1, sector)
+#define all_stat_dec(gendiskp, field, sector) \
+		all_stat_add(gendiskp, field, -1, sector)
+
+#define __all_stat_inc(gendiskp, field, sector) \
+		__all_stat_add(gendiskp, field, 1, sector)
+#define all_stat_inc(gendiskp, field, sector) \
+		all_stat_add(gendiskp, field, 1, sector)
+
+#define __all_stat_sub(gendiskp, field, subnd, sector) \
+		__all_stat_add(gendiskp, field, -subnd, sector)
+#define all_stat_sub(gendiskp, field, subnd, sector) \
+		all_stat_add(gendiskp, field, -subnd, sector)
 
 /* Inlines to alloc and free disk stats in struct gendisk */
 #ifdef  CONFIG_SMP
···
 {
 	free_percpu(disk->dkstats);
 }
+
+static inline int init_part_stats(struct hd_struct *part)
+{
+	part->dkstats = alloc_percpu(struct disk_stats);
+	if (!part->dkstats)
+		return 0;
+	return 1;
+}
+
+static inline void free_part_stats(struct hd_struct *part)
+{
+	free_percpu(part->dkstats);
+}
+
 #else	/* CONFIG_SMP */
 static inline int init_disk_stats(struct gendisk *disk)
 {
···
 static inline void free_disk_stats(struct gendisk *disk)
 {
 }
+
+static inline int init_part_stats(struct hd_struct *part)
+{
+	return 1;
+}
+
+static inline void free_part_stats(struct hd_struct *part)
+{
+}
 #endif	/* CONFIG_SMP */
 
 /* drivers/block/ll_rw_blk.c */
 extern void disk_round_stats(struct gendisk *disk);
+extern void part_round_stats(struct hd_struct *part);
 
 /* drivers/block/genhd.c */
 extern int get_blkdev_list(char *, int);