diff options
| -rw-r--r-- | block/blk-core.c | 20 | ||||
| -rw-r--r-- | block/blk-merge.c | 9 | ||||
| -rw-r--r-- | block/genhd.c | 218 | ||||
| -rw-r--r-- | block/ioctl.c | 26 | ||||
| -rw-r--r-- | drivers/block/aoe/aoecmd.c | 6 | ||||
| -rw-r--r-- | fs/block_dev.c | 15 | ||||
| -rw-r--r-- | fs/partitions/check.c | 70 | ||||
| -rw-r--r-- | include/linux/genhd.h | 53 |
8 files changed, 323 insertions, 94 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index a0dc2e72fcbb..d6128d9ad601 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -60,7 +60,9 @@ static void drive_stat_acct(struct request *rq, int new_io) if (!blk_fs_request(rq) || !rq->rq_disk) return; - part = disk_map_sector(rq->rq_disk, rq->sector); + rcu_read_lock(); + + part = disk_map_sector_rcu(rq->rq_disk, rq->sector); if (!new_io) __all_stat_inc(rq->rq_disk, part, merges[rw], rq->sector); else { @@ -71,6 +73,8 @@ static void drive_stat_acct(struct request *rq, int new_io) part->in_flight++; } } + + rcu_read_unlock(); } void blk_queue_congestion_threshold(struct request_queue *q) @@ -1557,12 +1561,14 @@ static int __end_that_request_first(struct request *req, int error, } if (blk_fs_request(req) && req->rq_disk) { - struct hd_struct *part = - disk_map_sector(req->rq_disk, req->sector); const int rw = rq_data_dir(req); + struct hd_struct *part; + rcu_read_lock(); + part = disk_map_sector_rcu(req->rq_disk, req->sector); all_stat_add(req->rq_disk, part, sectors[rw], nr_bytes >> 9, req->sector); + rcu_read_unlock(); } total_bytes = bio_nbytes = 0; @@ -1746,7 +1752,11 @@ static void end_that_request_last(struct request *req, int error) 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 = disk_map_sector(disk, req->sector); + struct hd_struct *part; + + rcu_read_lock(); + + part = disk_map_sector_rcu(disk, req->sector); __all_stat_inc(disk, part, ios[rw], req->sector); __all_stat_add(disk, part, ticks[rw], duration, req->sector); @@ -1756,6 +1766,8 @@ static void end_that_request_last(struct request *req, int error) part_round_stats(part); part->in_flight--; } + + rcu_read_unlock(); } if (req->end_io) diff --git a/block/blk-merge.c b/block/blk-merge.c index 9b17da698d7c..eb2a3ca58303 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -387,14 +387,19 @@ static int attempt_merge(struct request_queue *q, struct request *req, elv_merge_requests(q, req, next); if (req->rq_disk) { - struct hd_struct *part = - disk_map_sector(req->rq_disk, req->sector); + struct hd_struct *part; + + rcu_read_lock(); + + part = disk_map_sector_rcu(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--; } + + rcu_read_unlock(); } req->ioprio = ioprio_best(req->ioprio, next->ioprio); diff --git a/block/genhd.c b/block/genhd.c index fa32d09fda24..b431d6543942 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -26,6 +26,158 @@ struct kobject *block_depr; static struct device_type disk_type; +/** + * disk_get_part - get partition + * @disk: disk to look partition from + * @partno: partition number + * + * Look for partition @partno from @disk. If found, increment + * reference count and return it. + * + * CONTEXT: + * Don't care. + * + * RETURNS: + * Pointer to the found partition on success, NULL if not found. + */ +struct hd_struct *disk_get_part(struct gendisk *disk, int partno) +{ + struct hd_struct *part; + + if (unlikely(partno < 1 || partno > disk_max_parts(disk))) + return NULL; + rcu_read_lock(); + part = rcu_dereference(disk->__part[partno - 1]); + if (part) + get_device(&part->dev); + rcu_read_unlock(); + + return part; +} +EXPORT_SYMBOL_GPL(disk_get_part); + +/** + * disk_part_iter_init - initialize partition iterator + * @piter: iterator to initialize + * @disk: disk to iterate over + * @flags: DISK_PITER_* flags + * + * Initialize @piter so that it iterates over partitions of @disk. + * + * CONTEXT: + * Don't care. + */ +void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, + unsigned int flags) +{ + piter->disk = disk; + piter->part = NULL; + + if (flags & DISK_PITER_REVERSE) + piter->idx = disk_max_parts(piter->disk) - 1; + else + piter->idx = 0; + + piter->flags = flags; +} +EXPORT_SYMBOL_GPL(disk_part_iter_init); + +/** + * disk_part_iter_next - proceed iterator to the next partition and return it + * @piter: iterator of interest + * + * Proceed @piter to the next partition and return it. + * + * CONTEXT: + * Don't care. + */ +struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) +{ + int inc, end; + + /* put the last partition */ + disk_put_part(piter->part); + piter->part = NULL; + + rcu_read_lock(); + + /* determine iteration parameters */ + if (piter->flags & DISK_PITER_REVERSE) { + inc = -1; + end = -1; + } else { + inc = 1; + end = disk_max_parts(piter->disk); + } + + /* iterate to the next partition */ + for (; piter->idx != end; piter->idx += inc) { + struct hd_struct *part; + + part = rcu_dereference(piter->disk->__part[piter->idx]); + if (!part) + continue; + if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects) + continue; + + get_device(&part->dev); + piter->part = part; + piter->idx += inc; + break; + } + + rcu_read_unlock(); + + return piter->part; +} +EXPORT_SYMBOL_GPL(disk_part_iter_next); + +/** + * disk_part_iter_exit - finish up partition iteration + * @piter: iter of interest + * + * Called when iteration is over. Cleans up @piter. + * + * CONTEXT: + * Don't care. + */ +void disk_part_iter_exit(struct disk_part_iter *piter) +{ + disk_put_part(piter->part); + piter->part = NULL; +} +EXPORT_SYMBOL_GPL(disk_part_iter_exit); + +/** + * disk_map_sector_rcu - map sector to partition + * @disk: gendisk of interest + * @sector: sector to map + * + * Find out which partition @sector maps to on @disk. This is + * primarily used for stats accounting. + * + * CONTEXT: + * RCU read locked. The returned partition pointer is valid only + * while preemption is disabled. + * + * RETURNS: + * Found partition on success, NULL if there's no matching partition. + */ +struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) +{ + int i; + + for (i = 0; i < disk_max_parts(disk); i++) { + struct hd_struct *part = rcu_dereference(disk->__part[i]); + + if (part && part->start_sect <= sector && + sector < part->start_sect + part->nr_sects) + return part; + } + return NULL; +} +EXPORT_SYMBOL_GPL(disk_map_sector_rcu); + /* * Can be deleted altogether. Later. * @@ -245,10 +397,12 @@ extern struct block_device *bdget_disk(struct gendisk *disk, int partno) if (partno == 0) devt = disk_devt(disk); else { - struct hd_struct *part = disk->part[partno - 1]; + struct hd_struct *part; + part = disk_get_part(disk, partno); if (part && part->nr_sects) devt = part_devt(part); + disk_put_part(part); } if (likely(devt != MKDEV(0, 0))) @@ -270,8 +424,9 @@ void __init printk_all_partitions(void) class_dev_iter_init(&iter, &block_class, NULL, &disk_type); while ((dev = class_dev_iter_next(&iter))) { struct gendisk *disk = dev_to_disk(dev); + struct disk_part_iter piter; + struct hd_struct *part; char buf[BDEVNAME_SIZE]; - int n; /* * Don't show empty devices or things that have been @@ -298,16 +453,13 @@ void __init printk_all_partitions(void) printk(" (driver?)\n"); /* now show the partitions */ - for (n = 0; n < disk_max_parts(disk); ++n) { - struct hd_struct *part = disk->part[n]; - - if (!part || !part->nr_sects) - continue; + disk_part_iter_init(&piter, disk, 0); + while ((part = disk_part_iter_next(&piter))) printk(" %02x%02x %10llu %s\n", MAJOR(part_devt(part)), MINOR(part_devt(part)), (unsigned long long)part->nr_sects >> 1, disk_name(disk, part->partno, buf)); - } + disk_part_iter_exit(&piter); } class_dev_iter_exit(&iter); } @@ -371,7 +523,8 @@ static void *show_partition_start(struct seq_file *seqf, loff_t *pos) static int show_partition(struct seq_file *seqf, void *v) { struct gendisk *sgp = v; - int n; + struct disk_part_iter piter; + struct hd_struct *part; char buf[BDEVNAME_SIZE]; /* Don't show non-partitionable removeable devices or empty devices */ @@ -386,17 +539,14 @@ static int show_partition(struct seq_file *seqf, void *v) MAJOR(disk_devt(sgp)), MINOR(disk_devt(sgp)), (unsigned long long)get_capacity(sgp) >> 1, disk_name(sgp, 0, buf)); - for (n = 0; n < disk_max_parts(sgp); n++) { - struct hd_struct *part = sgp->part[n]; - if (!part) - continue; - if (part->nr_sects == 0) - continue; + + disk_part_iter_init(&piter, sgp, 0); + while ((part = disk_part_iter_next(&piter))) seq_printf(seqf, "%4d %4d %10llu %s\n", MAJOR(part_devt(part)), MINOR(part_devt(part)), (unsigned long long)part->nr_sects >> 1, disk_name(sgp, part->partno, buf)); - } + disk_part_iter_exit(&piter); return 0; } @@ -571,7 +721,7 @@ static void disk_release(struct device *dev) struct gendisk *disk = dev_to_disk(dev); kfree(disk->random); - kfree(disk->part); + kfree(disk->__part); free_disk_stats(disk); kfree(disk); } @@ -596,8 +746,9 @@ static struct device_type disk_type = { static int diskstats_show(struct seq_file *seqf, void *v) { struct gendisk *gp = v; + struct disk_part_iter piter; + struct hd_struct *hd; char buf[BDEVNAME_SIZE]; - int n; /* if (&gp->dev.kobj.entry == block_class.devices.next) @@ -624,12 +775,8 @@ static int diskstats_show(struct seq_file *seqf, void *v) jiffies_to_msecs(disk_stat_read(gp, time_in_queue))); /* now show all non-0 size partitions of it */ - for (n = 0; n < disk_max_parts(gp); n++) { - struct hd_struct *hd = gp->part[n]; - - if (!hd || !hd->nr_sects) - continue; - + disk_part_iter_init(&piter, gp, 0); + while ((hd = disk_part_iter_next(&piter))) { preempt_disable(); part_round_stats(hd); preempt_enable(); @@ -650,6 +797,7 @@ static int diskstats_show(struct seq_file *seqf, void *v) jiffies_to_msecs(part_stat_read(hd, time_in_queue)) ); } + disk_part_iter_exit(&piter); return 0; } @@ -703,12 +851,16 @@ dev_t blk_lookup_devt(const char *name, int partno) if (partno == 0) devt = disk_devt(disk); else { - struct hd_struct *part = disk->part[partno - 1]; + struct hd_struct *part; - if (!part || !part->nr_sects) + part = disk_get_part(disk, partno); + if (!part || !part->nr_sects) { + disk_put_part(part); continue; + } devt = part_devt(part); + disk_put_part(part); } break; } @@ -735,9 +887,9 @@ struct gendisk *alloc_disk_node(int minors, int node_id) } if (minors > 1) { int size = (minors - 1) * sizeof(struct hd_struct *); - disk->part = kmalloc_node(size, + disk->__part = kmalloc_node(size, GFP_KERNEL | __GFP_ZERO, node_id); - if (!disk->part) { + if (!disk->__part) { free_disk_stats(disk); kfree(disk); return NULL; @@ -798,10 +950,14 @@ EXPORT_SYMBOL(set_device_ro); void set_disk_ro(struct gendisk *disk, int flag) { - int i; + struct disk_part_iter piter; + struct hd_struct *part; + disk->policy = flag; - for (i = 0; i < disk_max_parts(disk); i++) - if (disk->part[i]) disk->part[i]->policy = flag; + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); + while ((part = disk_part_iter_next(&piter))) + part->policy = flag; + disk_part_iter_exit(&piter); } EXPORT_SYMBOL(set_disk_ro); diff --git a/block/ioctl.c b/block/ioctl.c index 403f7d7e0c28..a5f672ad55f6 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -12,11 +12,12 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user { struct block_device *bdevp; struct gendisk *disk; + struct hd_struct *part; struct blkpg_ioctl_arg a; struct blkpg_partition p; + struct disk_part_iter piter; long long start, length; int partno; - int i; int err; if (!capable(CAP_SYS_ADMIN)) @@ -47,28 +48,33 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user mutex_lock(&bdev->bd_mutex); /* overlap? */ - for (i = 0; i < disk_max_parts(disk); i++) { - struct hd_struct *s = disk->part[i]; - - if (!s) - continue; - if (!(start+length <= s->start_sect || - start >= s->start_sect + s->nr_sects)) { + disk_part_iter_init(&piter, disk, + DISK_PITER_INCL_EMPTY); + while ((part = disk_part_iter_next(&piter))) { + if (!(start + length <= part->start_sect || + start >= part->start_sect + part->nr_sects)) { + disk_part_iter_exit(&piter); mutex_unlock(&bdev->bd_mutex); return -EBUSY; } } + disk_part_iter_exit(&piter); + /* all seems OK */ err = add_partition(disk, partno, start, length, ADDPART_FLAG_NONE); mutex_unlock(&bdev->bd_mutex); return err; case BLKPG_DEL_PARTITION: - if (!disk->part[partno - 1]) + part = disk_get_part(disk, partno); + if (!part) return -ENXIO; - bdevp = bdget_disk(disk, partno); + + bdevp = bdget(part_devt(part)); + disk_put_part(part); if (!bdevp) return -ENOMEM; + mutex_lock(&bdevp->bd_mutex); if (bdevp->bd_openers) { mutex_unlock(&bdevp->bd_mutex); diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c index 885d1409521f..84c03d65dcc5 100644 --- a/drivers/block/aoe/aoecmd.c +++ b/drivers/block/aoe/aoecmd.c @@ -757,11 +757,15 @@ diskstats(struct gendisk *disk, struct bio *bio, ulong duration, sector_t sector const int rw = bio_data_dir(bio); struct hd_struct *part; - part = disk_map_sector(disk, sector); + rcu_read_lock(); + + part = disk_map_sector_rcu(disk, sector); all_stat_inc(disk, part, ios[rw], sector); all_stat_add(disk, part, ticks[rw], duration, sector); all_stat_add(disk, part, sectors[rw], n_sect, sector); all_stat_add(disk, part, io_ticks, duration, sector); + + rcu_read_unlock(); } void diff --git a/fs/block_dev.c b/fs/block_dev.c index 72e0a2887cb7..2f2873b9a041 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -929,6 +929,7 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part) { struct module *owner = NULL; struct gendisk *disk; + struct hd_struct *part = NULL; int ret; int partno; int perm = 0; @@ -978,7 +979,6 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part) if (bdev->bd_invalidated) rescan_partitions(disk, bdev); } else { - struct hd_struct *p; struct block_device *whole; whole = bdget_disk(disk, 0); ret = -ENOMEM; @@ -989,16 +989,16 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part) if (ret) goto out_first; bdev->bd_contains = whole; - p = disk->part[partno - 1]; + part = disk_get_part(disk, partno); bdev->bd_inode->i_data.backing_dev_info = whole->bd_inode->i_data.backing_dev_info; - if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) { + if (!(disk->flags & GENHD_FL_UP) || + !part || !part->nr_sects) { ret = -ENXIO; goto out_first; } - kobject_get(&p->dev.kobj); - bdev->bd_part = p; - bd_set_size(bdev, (loff_t) p->nr_sects << 9); + bdev->bd_part = part; + bd_set_size(bdev, (loff_t)part->nr_sects << 9); } } else { put_disk(disk); @@ -1027,6 +1027,7 @@ out_first: __blkdev_put(bdev->bd_contains, 1); bdev->bd_contains = NULL; put_disk(disk); + disk_put_part(part); module_put(owner); out: mutex_unlock(&bdev->bd_mutex); @@ -1119,7 +1120,7 @@ static int __blkdev_put(struct block_device *bdev, int for_part) module_put(owner); if (bdev->bd_contains != bdev) { - kobject_put(&bdev->bd_part->dev.kobj); + disk_put_part(bdev->bd_part); bdev->bd_part = NULL; } bdev->bd_disk = NULL; diff --git a/fs/partitions/check.c b/fs/partitions/check.c index e77fa144a07d..96c8bf41e455 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -314,19 +314,29 @@ static inline void disk_sysfs_add_subdirs(struct gendisk *disk) kobject_put(k); } +static void delete_partition_rcu_cb(struct rcu_head *head) +{ + struct hd_struct *part = container_of(head, struct hd_struct, rcu_head); + + part->start_sect = 0; + part->nr_sects = 0; + part_stat_set_all(part, 0); + put_device(&part->dev); +} + void delete_partition(struct gendisk *disk, int partno) { - struct hd_struct *p = disk->part[partno - 1]; + struct hd_struct *part; - if (!p) + part = disk->__part[partno-1]; + if (!part) return; - disk->part[partno - 1] = NULL; - p->start_sect = 0; - p->nr_sects = 0; - part_stat_set_all(p, 0); - kobject_put(p->holder_dir); - device_del(&p->dev); - put_device(&p->dev); + + rcu_assign_pointer(disk->__part[partno-1], NULL); + kobject_put(part->holder_dir); + device_del(&part->dev); + + call_rcu(&part->rcu_head, delete_partition_rcu_cb); } static ssize_t whole_disk_show(struct device *dev, @@ -343,7 +353,7 @@ int add_partition(struct gendisk *disk, int partno, struct hd_struct *p; int err; - if (disk->part[partno - 1]) + if (disk->__part[partno - 1]) return -EBUSY; p = kzalloc(sizeof(*p), GFP_KERNEL); @@ -391,7 +401,8 @@ int add_partition(struct gendisk *disk, int partno, } /* everything is up and running, commence */ - disk->part[partno - 1] = p; + INIT_RCU_HEAD(&p->rcu_head); + rcu_assign_pointer(disk->__part[partno - 1], p); /* suppress uevent if the disk supresses it */ if (!disk->dev.uevent_suppress) @@ -414,9 +425,9 @@ out_put: void register_disk(struct gendisk *disk) { struct block_device *bdev; + struct disk_part_iter piter; + struct hd_struct *part; char *s; - int i; - struct hd_struct *p; int err; disk->dev.parent = disk->driverfs_dev; @@ -466,16 +477,16 @@ exit: kobject_uevent(&disk->dev.kobj, KOBJ_ADD); /* announce possible partitions */ - for (i = 0; i < disk_max_parts(disk); i++) { - p = disk->part[i]; - if (!p || !p->nr_sects) - continue; - kobject_uevent(&p->dev.kobj, KOBJ_ADD); - } + disk_part_iter_init(&piter, disk, 0); + while ((part = disk_part_iter_next(&piter))) + kobject_uevent(&part->dev.kobj, KOBJ_ADD); + disk_part_iter_exit(&piter); } int rescan_partitions(struct gendisk *disk, struct block_device *bdev) { + struct disk_part_iter piter; + struct hd_struct *part; struct parsed_partitions *state; int p, res; @@ -485,8 +496,12 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev) if (res) return res; bdev->bd_invalidated = 0; - for (p = 1; p <= disk_max_parts(disk); p++) - delete_partition(disk, p); + + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); + while ((part = disk_part_iter_next(&piter))) + delete_partition(disk, part->partno); + disk_part_iter_exit(&piter); + if (disk->fops->revalidate_disk) disk->fops->revalidate_disk(disk); if (!get_capacity(disk) || !(state = check_partition(disk, bdev))) @@ -545,13 +560,18 @@ EXPORT_SYMBOL(read_dev_sector); void del_gendisk(struct gendisk *disk) { - int p; + struct disk_part_iter piter; + struct hd_struct *part; /* invalidate stuff */ - for (p = disk_max_parts(disk); p > 0; p--) { - invalidate_partition(disk, p); - delete_partition(disk, p); + disk_part_iter_init(&piter, disk, + DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE); + while ((part = disk_part_iter_next(&piter))) { + invalidate_partition(disk, part->partno); + delete_partition(disk, part->partno); } + disk_part_iter_exit(&piter); + invalidate_partition(disk, 0); disk->capacity = 0; disk->flags &= ~GENHD_FL_UP; diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 0ff75329199c..7fbba19e076b 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -11,6 +11,7 @@ #include <linux/types.h> #include <linux/kdev_t.h> +#include <linux/rcupdate.h> #ifdef CONFIG_BLOCK @@ -100,6 +101,7 @@ struct hd_struct { #else struct disk_stats dkstats; #endif + struct rcu_head rcu_head; }; #define GENHD_FL_REMOVABLE 1 @@ -120,7 +122,14 @@ struct gendisk { * disks that can't be partitioned. */ char disk_name[32]; /* name of major driver */ - struct hd_struct **part; /* [indexed by minor - 1] */ + + /* Array of pointers to partitions indexed by partno - 1. + * Protected with matching bdev lock but stat and other + * non-critical accesses use RCU. Always access through + * helpers. + */ + struct hd_struct **__part; + struct block_device_operations *fops; struct request_queue *queue; void *private_data; @@ -171,25 +180,41 @@ static inline dev_t part_devt(struct hd_struct *part) return part->dev.devt; } +extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno); + +static inline void disk_put_part(struct hd_struct *part) +{ + if (likely(part)) + put_device(&part->dev); +} + +/* + * Smarter partition iterator without context limits. + */ +#define DISK_PITER_REVERSE (1 << 0) /* iterate in the reverse direction */ +#define DISK_PITER_INCL_EMPTY (1 << 1) /* include 0-sized parts */ + +struct disk_part_iter { + struct gendisk *disk; + struct hd_struct *part; + int idx; + unsigned int flags; +}; + +extern void disk_part_iter_init(struct disk_part_iter *piter, + struct gendisk *disk, unsigned int flags); +extern struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter); +extern void disk_part_iter_exit(struct disk_part_iter *piter); + +extern struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, + sector_t sector); + /* * Macros to operate on percpu disk statistics: * * The __ variants should only be called in critical sections. The full * variants disable/enable preemption. */ -static inline struct hd_struct *disk_map_sector(struct gendisk *gendiskp, - sector_t sector) -{ - struct hd_struct *part; - int i; - for (i = 0; i < disk_max_parts(gendiskp); 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) \ |