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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: "Justin Sanders" <justin@coraid.com>,
	"Josef Bacik" <josef@toxicpanda.com>,
	"Ilya Dryomov" <idryomov@gmail.com>,
	"Jack Wang" <jinpu.wang@cloud.ionos.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>,
	"Minchan Kim" <minchan@kernel.org>,
	"Mike Snitzer" <snitzer@redhat.com>, "Song Liu" <song@kernel.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	dm-devel@redhat.com, linux-block@vger.kernel.org,
	drbd-dev@lists.linbit.com, nbd@other.debian.org,
	ceph-devel@vger.kernel.org, xen-devel@lists.xenproject.org,
	linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 36/78] block: open code kobj_map into in block/genhd.c
Date: Mon, 16 Nov 2020 15:57:27 +0100
Message-ID: <20201116145809.410558-37-hch@lst.de> (raw)
In-Reply-To: <20201116145809.410558-1-hch@lst.de>

Copy and paste the kobj_map functionality in the block code in preparation
for completely rewriting it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 130 +++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 117 insertions(+), 13 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 8180195b76634b..482f7b89802010 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -17,7 +17,6 @@
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/kmod.h>
-#include <linux/kobj_map.h>
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/log2.h>
@@ -29,6 +28,16 @@
 static DEFINE_MUTEX(block_class_lock);
 static struct kobject *block_depr;
 
+struct bdev_map {
+	struct bdev_map *next;
+	dev_t dev;
+	unsigned long range;
+	struct module *owner;
+	struct kobject *(*probe)(dev_t, int *, void *);
+	int (*lock)(dev_t, void *);
+	void *data;
+} *bdev_map[255];
+
 /* for extended dynamic devt allocation, currently only one major is used */
 #define NR_EXT_DEVT		(1 << MINORBITS)
 
@@ -517,8 +526,6 @@ void unregister_blkdev(unsigned int major, const char *name)
 
 EXPORT_SYMBOL(unregister_blkdev);
 
-static struct kobj_map *bdev_map;
-
 /**
  * blk_mangle_minor - scatter minor numbers apart
  * @minor: minor number to mangle
@@ -645,16 +652,60 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module,
 			 struct kobject *(*probe)(dev_t, int *, void *),
 			 int (*lock)(dev_t, void *), void *data)
 {
-	kobj_map(bdev_map, devt, range, module, probe, lock, data);
-}
+	unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1;
+	unsigned index = MAJOR(devt);
+	unsigned i;
+	struct bdev_map *p;
+
+	n = min(n, 255u);
+	p = kmalloc_array(n, sizeof(struct bdev_map), GFP_KERNEL);
+	if (p == NULL)
+		return;
 
+	for (i = 0; i < n; i++, p++) {
+		p->owner = module;
+		p->probe = probe;
+		p->lock = lock;
+		p->dev = devt;
+		p->range = range;
+		p->data = data;
+	}
+
+	mutex_lock(&block_class_lock);
+	for (i = 0, p -= n; i < n; i++, p++, index++) {
+		struct bdev_map **s = &bdev_map[index % 255];
+		while (*s && (*s)->range < range)
+			s = &(*s)->next;
+		p->next = *s;
+		*s = p;
+	}
+	mutex_unlock(&block_class_lock);
+}
 EXPORT_SYMBOL(blk_register_region);
 
 void blk_unregister_region(dev_t devt, unsigned long range)
 {
-	kobj_unmap(bdev_map, devt, range);
-}
+	unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1;
+	unsigned index = MAJOR(devt);
+	unsigned i;
+	struct bdev_map *found = NULL;
 
+	mutex_lock(&block_class_lock);
+	for (i = 0; i < min(n, 255u); i++, index++) {
+		struct bdev_map **s;
+		for (s = &bdev_map[index % 255]; *s; s = &(*s)->next) {
+			struct bdev_map *p = *s;
+			if (p->dev == devt && p->range == range) {
+				*s = p->next;
+				if (!found)
+					found = p;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&block_class_lock);
+	kfree(found);
+}
 EXPORT_SYMBOL(blk_unregister_region);
 
 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
@@ -976,6 +1027,47 @@ static ssize_t disk_badblocks_store(struct device *dev,
 	return badblocks_store(disk->bb, page, len, 0);
 }
 
+static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
+{
+	struct kobject *kobj;
+	struct bdev_map *p;
+	unsigned long best = ~0UL;
+
+retry:
+	mutex_lock(&block_class_lock);
+	for (p = bdev_map[MAJOR(dev) % 255]; p; p = p->next) {
+		struct kobject *(*probe)(dev_t, int *, void *);
+		struct module *owner;
+		void *data;
+
+		if (p->dev > dev || p->dev + p->range - 1 < dev)
+			continue;
+		if (p->range - 1 >= best)
+			break;
+		if (!try_module_get(p->owner))
+			continue;
+		owner = p->owner;
+		data = p->data;
+		probe = p->probe;
+		best = p->range - 1;
+		*partno = dev - p->dev;
+		if (p->lock && p->lock(dev, data) < 0) {
+			module_put(owner);
+			continue;
+		}
+		mutex_unlock(&block_class_lock);
+		kobj = probe(dev, partno, data);
+		/* Currently ->owner protects _only_ ->probe() itself. */
+		module_put(owner);
+		if (kobj)
+			return dev_to_disk(kobj_to_dev(kobj));
+		goto retry;
+	}
+	mutex_unlock(&block_class_lock);
+	return NULL;
+}
+
+
 /**
  * get_gendisk - get partitioning information for a given device
  * @devt: device to get partitioning information for
@@ -993,11 +1085,7 @@ struct gendisk *get_gendisk(dev_t devt, int *partno)
 	might_sleep();
 
 	if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
-		struct kobject *kobj;
-
-		kobj = kobj_lookup(bdev_map, devt, partno);
-		if (kobj)
-			disk = dev_to_disk(kobj_to_dev(kobj));
+		disk = lookup_gendisk(devt, partno);
 	} else {
 		struct hd_struct *part;
 
@@ -1210,6 +1298,22 @@ static struct kobject *base_probe(dev_t devt, int *partno, void *data)
 	return NULL;
 }
 
+static void bdev_map_init(void)
+{
+	struct bdev_map *base;
+	int i;
+
+	base = kzalloc(sizeof(*base), GFP_KERNEL);
+	if (!base)
+		panic("cannot allocate bdev_map");
+
+	base->dev = 1;
+	base->range = ~0 ;
+	base->probe = base_probe;
+	for (i = 0; i < 255; i++)
+		bdev_map[i] = base;
+}
+
 static int __init genhd_device_init(void)
 {
 	int error;
@@ -1218,7 +1322,7 @@ static int __init genhd_device_init(void)
 	error = class_register(&block_class);
 	if (unlikely(error))
 		return error;
-	bdev_map = kobj_map_init(base_probe, &block_class_lock);
+	bdev_map_init();
 	blk_dev_init();
 
 	register_blkdev(BLOCK_EXT_MAJOR, "blkext");
-- 
2.29.2


  parent reply index

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-16 14:56 cleanup updating the size of block devices v3 Christoph Hellwig
2020-11-16 14:56 ` [PATCH 01/78] block: remove the call to __invalidate_device in check_disk_size_change Christoph Hellwig
2020-11-16 14:56 ` [PATCH 02/78] loop: let set_capacity_revalidate_and_notify update the bdev size Christoph Hellwig
2020-11-16 14:56 ` [PATCH 03/78] nvme: " Christoph Hellwig
2020-11-16 14:56 ` [PATCH 04/78] sd: update the bdev size in sd_revalidate_disk Christoph Hellwig
2020-11-16 14:56 ` [PATCH 05/78] block: remove the update_bdev parameter to set_capacity_revalidate_and_notify Christoph Hellwig
2020-11-16 14:56 ` [PATCH 06/78] nbd: remove the call to set_blocksize Christoph Hellwig
2020-11-16 14:56 ` [PATCH 07/78] nbd: move the task_recv check into nbd_size_update Christoph Hellwig
2020-11-16 14:56 ` [PATCH 08/78] nbd: refactor size updates Christoph Hellwig
2020-11-16 14:57 ` [PATCH 09/78] nbd: validate the block size in nbd_set_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 10/78] nbd: use set_capacity_and_notify Christoph Hellwig
2020-11-16 14:57 ` [PATCH 11/78] aoe: don't call set_capacity from irq context Christoph Hellwig
2020-11-16 14:57 ` [PATCH 12/78] dm: use set_capacity_and_notify Christoph Hellwig
2021-02-12 15:45   ` Mike Snitzer
2021-02-16 11:46     ` Christoph Hellwig
2020-11-16 14:57 ` [PATCH 13/78] pktcdvd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 14/78] nvme: use set_capacity_and_notify in nvme_set_queue_dying Christoph Hellwig
2020-11-16 14:57 ` [PATCH 15/78] drbd: use set_capacity_and_notify Christoph Hellwig
2020-11-16 14:57 ` [PATCH 16/78] rbd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 17/78] rnbd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 18/78] zram: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 19/78] dm-raid: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 20/78] md: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 21/78] md: remove a spurious call to revalidate_disk_size in update_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 22/78] virtio-blk: remove a spurious call to revalidate_disk_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 23/78] block: unexport revalidate_disk_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 24/78] mtd_blkdevs: don't override BLKFLSBUF Christoph Hellwig
2020-11-16 14:57 ` [PATCH 25/78] block: don't call into the driver for BLKFLSBUF Christoph Hellwig
2020-11-16 14:57 ` [PATCH 26/78] block: add a new set_read_only method Christoph Hellwig
2020-11-16 14:57 ` [PATCH 27/78] rbd: implement ->set_read_only to hook into BLKROSET processing Christoph Hellwig
2020-11-16 14:57 ` [PATCH 28/78] md: " Christoph Hellwig
2020-11-16 17:37   ` Song Liu
2020-11-16 14:57 ` [PATCH 29/78] dasd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 30/78] block: don't call into the driver for BLKROSET Christoph Hellwig
2020-11-20  7:19   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 31/78] loop: use set_disk_ro Christoph Hellwig
2020-11-20  7:20   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 32/78] block: remove set_device_ro Christoph Hellwig
2020-11-20  7:20   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 33/78] block: remove __blkdev_driver_ioctl Christoph Hellwig
2020-11-20  7:22   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 34/78] block: propagate BLKROSET to all partitions Christoph Hellwig
2020-11-20  7:23   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 35/78] block: cleanup del_gendisk a bit Christoph Hellwig
2020-11-16 14:57 ` Christoph Hellwig [this message]
2020-11-16 14:57 ` [PATCH 37/78] block: split block_class_lock Christoph Hellwig
2020-11-16 14:57 ` [PATCH 38/78] block: rework requesting modules for unclaimed devices Christoph Hellwig
2020-11-16 14:57 ` [PATCH 39/78] block: add an optional probe callback to major_names Christoph Hellwig
2020-11-16 14:57 ` [PATCH 40/78] ide: remove ide_{,un}register_region Christoph Hellwig
2020-11-16 14:57 ` [PATCH 41/78] swim: don't call blk_register_region Christoph Hellwig
2020-11-16 14:57 ` [PATCH 42/78] sd: use __register_blkdev to avoid a modprobe for an unregistered dev_t Christoph Hellwig
2020-11-16 14:57 ` [PATCH 43/78] brd: use __register_blkdev to allocate devices on demand Christoph Hellwig
2020-11-16 14:57 ` [PATCH 44/78] loop: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 45/78] md: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 46/78] ide: switch to __register_blkdev for command set probing Christoph Hellwig
2020-11-16 14:57 ` [PATCH 47/78] floppy: use a separate gendisk for each media format Christoph Hellwig
2020-11-16 14:57 ` [PATCH 48/78] amiflop: use separate gendisks for Amiga vs MS-DOS mode Christoph Hellwig
2020-11-16 14:57 ` [PATCH 49/78] ataflop: use a separate gendisk for each media format Christoph Hellwig
2020-11-16 14:57 ` [PATCH 50/78] z2ram: reindent Christoph Hellwig
2020-11-16 14:57 ` [PATCH 51/78] z2ram: use separate gendisk for the different modes Christoph Hellwig
2020-11-16 14:57 ` [PATCH 52/78] block: switch gendisk lookup to a simple xarray Christoph Hellwig
2020-11-16 14:57 ` [PATCH 53/78] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
2020-11-20  7:25   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 54/78] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
2020-11-20  7:25   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 55/78] block: change the hash used for looking up block devices Christoph Hellwig
2020-11-20  7:26   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 56/78] init: refactor name_to_dev_t Christoph Hellwig
2020-11-20  7:31   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 57/78] init: refactor devt_from_partuuid Christoph Hellwig
2020-11-20  7:33   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 58/78] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
2020-11-20  7:34   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 59/78] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
2020-11-20  7:35   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 60/78] zram: remove the claim mechanism Christoph Hellwig
2020-11-20  7:37   ` Hannes Reinecke
2020-11-26  1:11   ` Minchan Kim
2020-11-26  9:59     ` Christoph Hellwig
2020-11-16 14:57 ` [PATCH 61/78] zram: do not call set_blocksize Christoph Hellwig
2020-11-20  7:38   ` Hannes Reinecke
2020-11-26  1:16   ` Minchan Kim
2020-11-16 14:57 ` [PATCH 62/78] loop: " Christoph Hellwig
2020-11-20  7:38   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 63/78] bcache: remove a superflous lookup_bdev all Christoph Hellwig
2020-11-16 14:57 ` [PATCH 64/78] dm: simplify flush_bio initialization in __send_empty_flush Christoph Hellwig
2020-11-20  7:41   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 65/78] dm: remove the block_device reference in struct mapped_device Christoph Hellwig
2020-11-20  7:43   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 66/78] block: keep a block_device reference for each hd_struct Christoph Hellwig
2020-11-20  7:50   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 67/78] block: simplify the block device claiming interface Christoph Hellwig
2020-11-20  7:51   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 68/78] block: remove ->bd_contains Christoph Hellwig
2020-11-20  7:52   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 69/78] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
2020-11-20  7:55   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 70/78] block: replace bd_mutex with a per-gendisk mutex Christoph Hellwig
2020-11-20  7:58   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 71/78] block: add a bdev_kobj helper Christoph Hellwig
2020-11-20  7:59   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 72/78] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
2020-11-20  7:59   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 73/78] block: use put_device in put_disk Christoph Hellwig
2020-11-20  8:02   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 74/78] block: merge struct block_device and struct hd_struct Christoph Hellwig
2020-11-20  8:58   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 75/78] block: stop using bdget_disk for partition 0 Christoph Hellwig
2020-11-16 14:58 ` [PATCH 76/78] filemap: use ->f_mapping over ->i_mapping consistently Christoph Hellwig
2020-11-16 14:58 ` [PATCH 77/78] fs: simplify the get_super_thawed interface Christoph Hellwig
2020-11-16 14:58 ` [PATCH 78/78] block: remove i_bdev Christoph Hellwig
2020-11-16 15:05 ` cleanup updating the size of block devices v3 Christoph Hellwig
2020-11-16 15:40 ` Jens Axboe

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