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-rw-r--r--block/genhd.c129
-rw-r--r--block/ioctl.c2
-rw-r--r--fs/partitions/check.c31
-rw-r--r--include/linux/genhd.h19
4 files changed, 154 insertions, 27 deletions
diff --git a/block/genhd.c b/block/genhd.c
index e1cb96fb883e..c2b14aa69d58 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -52,14 +52,21 @@ static struct device_type disk_type;
*/
struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
{
- struct hd_struct *part;
+ struct hd_struct *part = NULL;
+ struct disk_part_tbl *ptbl;
- if (unlikely(partno < 0 || partno >= disk_max_parts(disk)))
+ if (unlikely(partno < 0))
return NULL;
+
rcu_read_lock();
- part = rcu_dereference(disk->__part[partno]);
- if (part)
- get_device(part_to_dev(part));
+
+ ptbl = rcu_dereference(disk->part_tbl);
+ if (likely(partno < ptbl->len)) {
+ part = rcu_dereference(ptbl->part[partno]);
+ if (part)
+ get_device(part_to_dev(part));
+ }
+
rcu_read_unlock();
return part;
@@ -80,17 +87,24 @@ EXPORT_SYMBOL_GPL(disk_get_part);
void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
unsigned int flags)
{
+ struct disk_part_tbl *ptbl;
+
+ rcu_read_lock();
+ ptbl = rcu_dereference(disk->part_tbl);
+
piter->disk = disk;
piter->part = NULL;
if (flags & DISK_PITER_REVERSE)
- piter->idx = disk_max_parts(piter->disk) - 1;
+ piter->idx = ptbl->len - 1;
else if (flags & DISK_PITER_INCL_PART0)
piter->idx = 0;
else
piter->idx = 1;
piter->flags = flags;
+
+ rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(disk_part_iter_init);
@@ -105,13 +119,16 @@ EXPORT_SYMBOL_GPL(disk_part_iter_init);
*/
struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
{
+ struct disk_part_tbl *ptbl;
int inc, end;
/* put the last partition */
disk_put_part(piter->part);
piter->part = NULL;
+ /* get part_tbl */
rcu_read_lock();
+ ptbl = rcu_dereference(piter->disk->part_tbl);
/* determine iteration parameters */
if (piter->flags & DISK_PITER_REVERSE) {
@@ -122,14 +139,14 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
end = 0;
} else {
inc = 1;
- end = disk_max_parts(piter->disk);
+ end = ptbl->len;
}
/* iterate to the next partition */
for (; piter->idx != end; piter->idx += inc) {
struct hd_struct *part;
- part = rcu_dereference(piter->disk->__part[piter->idx]);
+ part = rcu_dereference(ptbl->part[piter->idx]);
if (!part)
continue;
if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects)
@@ -180,10 +197,13 @@ EXPORT_SYMBOL_GPL(disk_part_iter_exit);
*/
struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
{
+ struct disk_part_tbl *ptbl;
int i;
- for (i = 1; i < disk_max_parts(disk); i++) {
- struct hd_struct *part = rcu_dereference(disk->__part[i]);
+ ptbl = rcu_dereference(disk->part_tbl);
+
+ for (i = 1; i < ptbl->len; i++) {
+ struct hd_struct *part = rcu_dereference(ptbl->part[i]);
if (part && part->start_sect <= sector &&
sector < part->start_sect + part->nr_sects)
@@ -798,12 +818,86 @@ static struct attribute_group *disk_attr_groups[] = {
NULL
};
+static void disk_free_ptbl_rcu_cb(struct rcu_head *head)
+{
+ struct disk_part_tbl *ptbl =
+ container_of(head, struct disk_part_tbl, rcu_head);
+
+ kfree(ptbl);
+}
+
+/**
+ * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
+ * @disk: disk to replace part_tbl for
+ * @new_ptbl: new part_tbl to install
+ *
+ * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The
+ * original ptbl is freed using RCU callback.
+ *
+ * LOCKING:
+ * Matching bd_mutx locked.
+ */
+static void disk_replace_part_tbl(struct gendisk *disk,
+ struct disk_part_tbl *new_ptbl)
+{
+ struct disk_part_tbl *old_ptbl = disk->part_tbl;
+
+ rcu_assign_pointer(disk->part_tbl, new_ptbl);
+ if (old_ptbl)
+ call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
+}
+
+/**
+ * disk_expand_part_tbl - expand disk->part_tbl
+ * @disk: disk to expand part_tbl for
+ * @partno: expand such that this partno can fit in
+ *
+ * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl
+ * uses RCU to allow unlocked dereferencing for stats and other stuff.
+ *
+ * LOCKING:
+ * Matching bd_mutex locked, might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int disk_expand_part_tbl(struct gendisk *disk, int partno)
+{
+ struct disk_part_tbl *old_ptbl = disk->part_tbl;
+ struct disk_part_tbl *new_ptbl;
+ int len = old_ptbl ? old_ptbl->len : 0;
+ int target = partno + 1;
+ size_t size;
+ int i;
+
+ /* disk_max_parts() is zero during initialization, ignore if so */
+ if (disk_max_parts(disk) && target > disk_max_parts(disk))
+ return -EINVAL;
+
+ if (target <= len)
+ return 0;
+
+ size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
+ new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
+ if (!new_ptbl)
+ return -ENOMEM;
+
+ INIT_RCU_HEAD(&new_ptbl->rcu_head);
+ new_ptbl->len = target;
+
+ for (i = 0; i < len; i++)
+ rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
+
+ disk_replace_part_tbl(disk, new_ptbl);
+ return 0;
+}
+
static void disk_release(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
kfree(disk->random);
- kfree(disk->__part);
+ disk_replace_part_tbl(disk, NULL);
free_part_stats(&disk->part0);
kfree(disk);
}
@@ -948,22 +1042,16 @@ struct gendisk *alloc_disk_ext_node(int minors, int ext_minors, int node_id)
disk = kmalloc_node(sizeof(struct gendisk),
GFP_KERNEL | __GFP_ZERO, node_id);
if (disk) {
- int tot_minors = minors + ext_minors;
- int size = tot_minors * sizeof(struct hd_struct *);
-
if (!init_part_stats(&disk->part0)) {
kfree(disk);
return NULL;
}
-
- disk->__part = kmalloc_node(size, GFP_KERNEL | __GFP_ZERO,
- node_id);
- if (!disk->__part) {
- free_part_stats(&disk->part0);
+ if (disk_expand_part_tbl(disk, 0)) {
+ free_part_stats(&disk->part0);
kfree(disk);
return NULL;
}
- disk->__part[0] = &disk->part0;
+ disk->part_tbl->part[0] = &disk->part0;
disk->minors = minors;
disk->ext_minors = ext_minors;
@@ -973,6 +1061,7 @@ struct gendisk *alloc_disk_ext_node(int minors, int ext_minors, int node_id)
device_initialize(disk_to_dev(disk));
INIT_WORK(&disk->async_notify,
media_change_notify_thread);
+ disk->node_id = node_id;
}
return disk;
}
diff --git a/block/ioctl.c b/block/ioctl.c
index 64e7c67a64b0..38bee321e1fa 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -30,7 +30,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
if (bdev != bdev->bd_contains)
return -EINVAL;
partno = p.pno;
- if (partno <= 0 || partno >= disk_max_parts(disk))
+ if (partno <= 0)
return -EINVAL;
switch (a.op) {
case BLKPG_ADD_PARTITION:
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index f517869e8d10..772b2ed8d239 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -312,14 +312,18 @@ static void delete_partition_rcu_cb(struct rcu_head *head)
void delete_partition(struct gendisk *disk, int partno)
{
+ struct disk_part_tbl *ptbl = disk->part_tbl;
struct hd_struct *part;
- part = disk->__part[partno];
+ if (partno >= ptbl->len)
+ return;
+
+ part = ptbl->part[partno];
if (!part)
return;
blk_free_devt(part_devt(part));
- rcu_assign_pointer(disk->__part[partno], NULL);
+ rcu_assign_pointer(ptbl->part[partno], NULL);
kobject_put(part->holder_dir);
device_del(part_to_dev(part));
@@ -341,10 +345,16 @@ int add_partition(struct gendisk *disk, int partno,
dev_t devt = MKDEV(0, 0);
struct device *ddev = disk_to_dev(disk);
struct device *pdev;
+ struct disk_part_tbl *ptbl;
const char *dname;
int err;
- if (disk->__part[partno])
+ err = disk_expand_part_tbl(disk, partno);
+ if (err)
+ return err;
+ ptbl = disk->part_tbl;
+
+ if (ptbl->part[partno])
return -EBUSY;
p = kzalloc(sizeof(*p), GFP_KERNEL);
@@ -398,7 +408,7 @@ int add_partition(struct gendisk *disk, int partno,
/* everything is up and running, commence */
INIT_RCU_HEAD(&p->rcu_head);
- rcu_assign_pointer(disk->__part[partno], p);
+ rcu_assign_pointer(ptbl->part[partno], p);
/* suppress uevent if the disk supresses it */
if (!ddev->uevent_suppress)
@@ -487,7 +497,7 @@ 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;
+ int p, highest, res;
if (bdev->bd_part_count)
return -EBUSY;
@@ -511,6 +521,17 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
/* tell userspace that the media / partition table may have changed */
kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+ /* Detect the highest partition number and preallocate
+ * disk->part_tbl. This is an optimization and not strictly
+ * necessary.
+ */
+ for (p = 1, highest = 0; p < state->limit; p++)
+ if (state->parts[p].size)
+ highest = p;
+
+ disk_expand_part_tbl(disk, highest);
+
+ /* add partitions */
for (p = 1; p < state->limit; p++) {
sector_t size = state->parts[p].size;
sector_t from = state->parts[p].from;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index c90e1b4fbe5a..ecf649c3deed 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -113,6 +113,21 @@ struct hd_struct {
#define GENHD_FL_UP 16
#define GENHD_FL_SUPPRESS_PARTITION_INFO 32
+#define BLK_SCSI_MAX_CMDS (256)
+#define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
+
+struct blk_scsi_cmd_filter {
+ unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
+ unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
+ struct kobject kobj;
+};
+
+struct disk_part_tbl {
+ struct rcu_head rcu_head;
+ int len;
+ struct hd_struct *part[];
+};
+
struct gendisk {
/* major, first_minor, minors and ext_minors are input
* parameters only, don't use directly. Use disk_devt() and
@@ -131,7 +146,7 @@ struct gendisk {
* non-critical accesses use RCU. Always access through
* helpers.
*/
- struct hd_struct **__part;
+ struct disk_part_tbl *part_tbl;
struct hd_struct part0;
struct block_device_operations *fops;
@@ -149,6 +164,7 @@ struct gendisk {
#ifdef CONFIG_BLK_DEV_INTEGRITY
struct blk_integrity *integrity;
#endif
+ int node_id;
};
static inline struct gendisk *part_to_disk(struct hd_struct *part)
@@ -503,6 +519,7 @@ extern void blk_free_devt(dev_t devt);
extern dev_t blk_lookup_devt(const char *name, int partno);
extern char *disk_name (struct gendisk *hd, int partno, char *buf);
+extern int disk_expand_part_tbl(struct gendisk *disk, int target);
extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
extern int __must_check add_partition(struct gendisk *, int, sector_t, sector_t, int);
extern void delete_partition(struct gendisk *, int);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.