[PATCH 02/19] block: merge drivers/base/map.c into block/genhd.c

Christoph Hellwig
2020-08-30T06:27:40Z

Now that there is just a single user of the kobj_map functionality left,
merge it into the user to prepare for additional simplications.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
block/genhd.c | 130 +++++++++++++++++++++++++++++----
drivers/base/Makefile | 2 +-
drivers/base/map.c | 154 ---------------------------------------
include/linux/kobj_map.h | 20 -----
4 files changed, 118 insertions(+), 188 deletions(-)
delete mode 100644 drivers/base/map.c
delete mode 100644 include/linux/kobj_map.h

diff --git a/block/genhd.c b/block/genhd.c
index 99c64641c3148c..cb9a51be35b053 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)

@@ -520,8 +529,6 @@ 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
@@ -648,16 +655,60 @@ 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)
@@ -983,6 +1034,47 @@ 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
@@ -1000,11 +1092,7 @@ 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;

@@ -1217,6 +1305,22 @@ 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;
@@ -1225,7 +1329,7 @@ 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");
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 157452080f3d7f..4ffd2a785f5ed3 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -3,7 +3,7 @@

obj-y := component.o core.o bus.o dd.o syscore.o \
driver.o class.o platform.o \
- cpu.o firmware.o init.o map.o devres.o \
+ cpu.o firmware.o init.o devres.o \
attribute_container.o transport_class.o \
topology.o container.o property.o cacheinfo.o \
devcon.o swnode.o
diff --git a/drivers/base/map.c b/drivers/base/map.c
deleted file mode 100644
index 5650ab2b247ada..00000000000000
--- a/drivers/base/map.c
+++ /dev/null
@@ -1,154 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * linux/drivers/base/map.c
- *
- * (C) Copyright Al Viro 2002,2003
- *
- * NOTE: data structure needs to be changed. It works, but for large dev_t
- * it will be too slow. It is isolated, though, so these changes will be
- * local to that file.
- */
-
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/mutex.h>
-#include <linux/kdev_t.h>
-#include <linux/kobject.h>
-#include <linux/kobj_map.h>
-
-struct kobj_map {
- struct probe {
- struct probe *next;
- dev_t dev;
- unsigned long range;
- struct module *owner;
- kobj_probe_t *get;
- int (*lock)(dev_t, void *);
- void *data;
- } *probes[255];
- struct mutex *lock;
-};
-
-int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
- struct module *module, kobj_probe_t *probe,
- int (*lock)(dev_t, void *), void *data)
-{
- unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
- unsigned index = MAJOR(dev);
- unsigned i;
- struct probe *p;
-
- if (n > 255)
- n = 255;
-
- p = kmalloc_array(n, sizeof(struct probe), GFP_KERNEL);
- if (p == NULL)
- return -ENOMEM;
-
- for (i = 0; i < n; i++, p++) {
- p->owner = module;
- p->get = probe;
- p->lock = lock;
- p->dev = dev;
- p->range = range;
- p->data = data;
- }
- mutex_lock(domain->lock);
- for (i = 0, p -= n; i < n; i++, p++, index++) {
- struct probe **s = &domain->probes[index % 255];
- while (*s && (*s)->range < range)
- s = &(*s)->next;
- p->next = *s;
- *s = p;
- }
- mutex_unlock(domain->lock);
- return 0;
-}
-
-void kobj_unmap(struct kobj_map *domain, dev_t dev, unsigned long range)
-{
- unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
- unsigned index = MAJOR(dev);
- unsigned i;
- struct probe *found = NULL;
-
- if (n > 255)
- n = 255;
-
- mutex_lock(domain->lock);
- for (i = 0; i < n; i++, index++) {
- struct probe **s;
- for (s = &domain->probes[index % 255]; *s; s = &(*s)->next) {
- struct probe *p = *s;
- if (p->dev == dev && p->range == range) {
- *s = p->next;
- if (!found)
- found = p;
- break;
- }
- }
- }
- mutex_unlock(domain->lock);
- kfree(found);
-}
-
-struct kobject *kobj_lookup(struct kobj_map *domain, dev_t dev, int *index)
-{
- struct kobject *kobj;
- struct probe *p;
- unsigned long best = ~0UL;
-
-retry:
- mutex_lock(domain->lock);
- for (p = domain->probes[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->get;
- best = p->range - 1;
- *index = dev - p->dev;
- if (p->lock && p->lock(dev, data) < 0) {
- module_put(owner);
- continue;
- }
- mutex_unlock(domain->lock);
- kobj = probe(dev, index, data);
- /* Currently ->owner protects _only_ ->probe() itself. */
- module_put(owner);
- if (kobj)
- return kobj;
- goto retry;
- }
- mutex_unlock(domain->lock);
- return NULL;
-}
-
-struct kobj_map *kobj_map_init(kobj_probe_t *base_probe, struct mutex *lock)
-{
- struct kobj_map *p = kmalloc(sizeof(struct kobj_map), GFP_KERNEL);
- struct probe *base = kzalloc(sizeof(*base), GFP_KERNEL);
- int i;
-
- if ((p == NULL) || (base == NULL)) {
- kfree(p);
- kfree(base);
- return NULL;
- }
-
- base->dev = 1;
- base->range = ~0;
- base->get = base_probe;
- for (i = 0; i < 255; i++)
- p->probes[i] = base;
- p->lock = lock;
- return p;
-}
diff --git a/include/linux/kobj_map.h b/include/linux/kobj_map.h
deleted file mode 100644
index c9919f8b22932c..00000000000000
--- a/include/linux/kobj_map.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * kobj_map.h
- */
-
-#ifndef _KOBJ_MAP_H_
-#define _KOBJ_MAP_H_
-
-#include <linux/mutex.h>
-
-typedef struct kobject *kobj_probe_t(dev_t, int *, void *);
-struct kobj_map;
-
-int kobj_map(struct kobj_map *, dev_t, unsigned long, struct module *,
- kobj_probe_t *, int (*)(dev_t, void *), void *);
-void kobj_unmap(struct kobj_map *, dev_t, unsigned long);
-struct kobject *kobj_lookup(struct kobj_map *, dev_t, int *);
-struct kobj_map *kobj_map_init(kobj_probe_t *, struct mutex *);
-
-#endif /* _KOBJ_MAP_H_ */
--
2.28.0