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-rw-r--r--block/blk-core.c20
-rw-r--r--block/blk-merge.c9
-rw-r--r--block/genhd.c218
-rw-r--r--block/ioctl.c26
4 files changed, 226 insertions, 47 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index a0dc2e72fcb..d6128d9ad60 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 9b17da698d7..eb2a3ca5830 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 fa32d09fda2..b431d654394 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 403f7d7e0c2..a5f672ad55f 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);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-19 19:24:37 +0000