None of the complicated overlapping regions bits of the kobj_map are required for the character device lookup, so just a trivial xarray instead.
Signed-off-by: Christoph Hellwig <[email protected]> --- drivers/base/Makefile | 5 +- drivers/base/map.c | 154 --------------------------------------- fs/char_dev.c | 93 ++++++++++++----------- fs/dcache.c | 1 - fs/internal.h | 5 -- include/linux/kobj_map.h | 20 ----- 6 files changed, 48 insertions(+), 230 deletions(-) delete mode 100644 drivers/base/map.c delete mode 100644 include/linux/kobj_map.h diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 5e7bf9669a81f8..ff0be4d875cfaf 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -1,9 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for the Linux device tree -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 \ +obj-y := component.o core.o bus.o dd.o syscore.o driver.o \ + class.o platform.o cpu.o firmware.o init.o devres.o \ attribute_container.o transport_class.o \ topology.o container.o property.o cacheinfo.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/fs/char_dev.c b/fs/char_dev.c index ba0ded7842a779..82c26ed407ff65 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -17,7 +17,6 @@ #include <linux/seq_file.h> #include <linux/kobject.h> -#include <linux/kobj_map.h> #include <linux/cdev.h> #include <linux/mutex.h> #include <linux/backing-dev.h> @@ -25,8 +24,7 @@ #include "internal.h" -static struct kobj_map *cdev_map; - +static DEFINE_XARRAY(cdev_map); static DEFINE_MUTEX(chrdevs_lock); #define CHRDEV_MAJOR_HASH_SIZE 255 @@ -367,6 +365,28 @@ void cdev_put(struct cdev *p) } } +static struct cdev *cdev_lookup(dev_t dev) +{ + struct cdev *cdev; + + mutex_lock(&chrdevs_lock); + cdev = xa_load(&cdev_map, dev); + if (!cdev) { + mutex_unlock(&chrdevs_lock); + if (request_module("char-major-%d-%d", + MAJOR(dev), MINOR(dev)) > 0) + /* Make old-style 2.4 aliases work */ + request_module("char-major-%d", MAJOR(dev)); + mutex_lock(&chrdevs_lock); + + cdev = xa_load(&cdev_map, dev); + } + if (cdev && !cdev_get(cdev)) + cdev = NULL; + mutex_unlock(&chrdevs_lock); + return cdev; +} + /* * Called every time a character special file is opened */ @@ -380,13 +400,10 @@ static int chrdev_open(struct inode *inode, struct file *filp) spin_lock(&cdev_lock); p = inode->i_cdev; if (!p) { - struct kobject *kobj; - int idx; spin_unlock(&cdev_lock); - kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx); - if (!kobj) + new = cdev_lookup(inode->i_rdev); + if (!new) return -ENXIO; - new = container_of(kobj, struct cdev, kobj); spin_lock(&cdev_lock); /* Check i_cdev again in case somebody beat us to it while we dropped the lock. */ @@ -454,18 +471,6 @@ const struct file_operations def_chr_fops = { .llseek = noop_llseek, }; -static struct kobject *exact_match(dev_t dev, int *part, void *data) -{ - struct cdev *p = data; - return &p->kobj; -} - -static int exact_lock(dev_t dev, void *data) -{ - struct cdev *p = data; - return cdev_get(p) ? 0 : -1; -} - /** * cdev_add() - add a char device to the system * @p: the cdev structure for the device @@ -478,7 +483,7 @@ static int exact_lock(dev_t dev, void *data) */ int cdev_add(struct cdev *p, dev_t dev, unsigned count) { - int error; + int error, i; p->dev = dev; p->count = count; @@ -486,14 +491,22 @@ int cdev_add(struct cdev *p, dev_t dev, unsigned count) if (WARN_ON(dev == WHITEOUT_DEV)) return -EBUSY; - error = kobj_map(cdev_map, dev, count, NULL, - exact_match, exact_lock, p); - if (error) - return error; + mutex_lock(&chrdevs_lock); + for (i = 0; i < count; i++) { + error = xa_insert(&cdev_map, dev + i, p, GFP_KERNEL); + if (error) + goto out_unwind; + } + mutex_unlock(&chrdevs_lock); kobject_get(p->kobj.parent); - return 0; + +out_unwind: + while (--i >= 0) + xa_erase(&cdev_map, dev + i); + mutex_unlock(&chrdevs_lock); + return error; } /** @@ -575,11 +588,6 @@ void cdev_device_del(struct cdev *cdev, struct device *dev) cdev_del(cdev); } -static void cdev_unmap(dev_t dev, unsigned count) -{ - kobj_unmap(cdev_map, dev, count); -} - /** * cdev_del() - remove a cdev from the system * @p: the cdev structure to be removed @@ -593,11 +601,16 @@ static void cdev_unmap(dev_t dev, unsigned count) */ void cdev_del(struct cdev *p) { - cdev_unmap(p->dev, p->count); + int i; + + mutex_lock(&chrdevs_lock); + for (i = 0; i < p->count; i++) + xa_erase(&cdev_map, p->dev + i); + mutex_unlock(&chrdevs_lock); + kobject_put(&p->kobj); } - static void cdev_default_release(struct kobject *kobj) { struct cdev *p = container_of(kobj, struct cdev, kobj); @@ -656,20 +669,6 @@ void cdev_init(struct cdev *cdev, const struct file_operations *fops) cdev->ops = fops; } -static struct kobject *base_probe(dev_t dev, int *part, void *data) -{ - if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0) - /* Make old-style 2.4 aliases work */ - request_module("char-major-%d", MAJOR(dev)); - return NULL; -} - -void __init chrdev_init(void) -{ - cdev_map = kobj_map_init(base_probe, &chrdevs_lock); -} - - /* Let modules do char dev stuff */ EXPORT_SYMBOL(register_chrdev_region); EXPORT_SYMBOL(unregister_chrdev_region); diff --git a/fs/dcache.c b/fs/dcache.c index 97e81a844a966c..3e0329b3de0a2d 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -3240,5 +3240,4 @@ void __init vfs_caches_init(void) files_maxfiles_init(); mnt_init(); bdev_cache_init(); - chrdev_init(); } diff --git a/fs/internal.h b/fs/internal.h index 77c50befbfbe96..a2985ee25c3b15 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -50,11 +50,6 @@ static inline int emergency_thaw_bdev(struct super_block *sb) extern int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, get_block_t *get_block, struct iomap *iomap); -/* - * char_dev.c - */ -extern void __init chrdev_init(void); - /* * fs_context.c */ 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_ */ -- 2.29.2
