diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-07 12:03:30 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-07 12:03:30 -0800 |
commit | 7affca3537d74365128e477b40c529d6f2fe86c8 (patch) | |
tree | 20be92bd240029182fc89c2c4f25401b7715dcae /include/linux/kref.h | |
parent | 356b95424cfb456e14a59eaa579422ce014c424b (diff) | |
parent | ff4b8a57f0aaa2882d444ca44b2b9b333d22a4df (diff) |
Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits)
arm: fix up some samsung merge sysdev conversion problems
firmware: Fix an oops on reading fw_priv->fw in sysfs loading file
Drivers:hv: Fix a bug in vmbus_driver_unregister()
driver core: remove __must_check from device_create_file
debugfs: add missing #ifdef HAS_IOMEM
arm: time.h: remove device.h #include
driver-core: remove sysdev.h usage.
clockevents: remove sysdev.h
arm: convert sysdev_class to a regular subsystem
arm: leds: convert sysdev_class to a regular subsystem
kobject: remove kset_find_obj_hinted()
m86k: gpio - convert sysdev_class to a regular subsystem
mips: txx9_sram - convert sysdev_class to a regular subsystem
mips: 7segled - convert sysdev_class to a regular subsystem
sh: dma - convert sysdev_class to a regular subsystem
sh: intc - convert sysdev_class to a regular subsystem
power: suspend - convert sysdev_class to a regular subsystem
power: qe_ic - convert sysdev_class to a regular subsystem
power: cmm - convert sysdev_class to a regular subsystem
s390: time - convert sysdev_class to a regular subsystem
...
Fix up conflicts with 'struct sysdev' removal from various platform
drivers that got changed:
- arch/arm/mach-exynos/cpu.c
- arch/arm/mach-exynos/irq-eint.c
- arch/arm/mach-s3c64xx/common.c
- arch/arm/mach-s3c64xx/cpu.c
- arch/arm/mach-s5p64x0/cpu.c
- arch/arm/mach-s5pv210/common.c
- arch/arm/plat-samsung/include/plat/cpu.h
- arch/powerpc/kernel/sysfs.c
and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h
Diffstat (limited to 'include/linux/kref.h')
-rw-r--r-- | include/linux/kref.h | 77 |
1 files changed, 71 insertions, 6 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h index d4a62ab2ee5..abc0120b09b 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -15,16 +15,81 @@ #ifndef _KREF_H_ #define _KREF_H_ -#include <linux/types.h> +#include <linux/bug.h> +#include <linux/atomic.h> struct kref { atomic_t refcount; }; -void kref_init(struct kref *kref); -void kref_get(struct kref *kref); -int kref_put(struct kref *kref, void (*release) (struct kref *kref)); -int kref_sub(struct kref *kref, unsigned int count, - void (*release) (struct kref *kref)); +/** + * kref_init - initialize object. + * @kref: object in question. + */ +static inline void kref_init(struct kref *kref) +{ + atomic_set(&kref->refcount, 1); +} + +/** + * kref_get - increment refcount for object. + * @kref: object. + */ +static inline void kref_get(struct kref *kref) +{ + WARN_ON(!atomic_read(&kref->refcount)); + atomic_inc(&kref->refcount); +} +/** + * kref_sub - subtract a number of refcounts for object. + * @kref: object. + * @count: Number of recounts to subtract. + * @release: pointer to the function that will clean up the object when the + * last reference to the object is released. + * This pointer is required, and it is not acceptable to pass kfree + * in as this function. If the caller does pass kfree to this + * function, you will be publicly mocked mercilessly by the kref + * maintainer, and anyone else who happens to notice it. You have + * been warned. + * + * Subtract @count from the refcount, and if 0, call release(). + * Return 1 if the object was removed, otherwise return 0. Beware, if this + * function returns 0, you still can not count on the kref from remaining in + * memory. Only use the return value if you want to see if the kref is now + * gone, not present. + */ +static inline int kref_sub(struct kref *kref, unsigned int count, + void (*release)(struct kref *kref)) +{ + WARN_ON(release == NULL); + + if (atomic_sub_and_test((int) count, &kref->refcount)) { + release(kref); + return 1; + } + return 0; +} + +/** + * kref_put - decrement refcount for object. + * @kref: object. + * @release: pointer to the function that will clean up the object when the + * last reference to the object is released. + * This pointer is required, and it is not acceptable to pass kfree + * in as this function. If the caller does pass kfree to this + * function, you will be publicly mocked mercilessly by the kref + * maintainer, and anyone else who happens to notice it. You have + * been warned. + * + * Decrement the refcount, and if 0, call release(). + * Return 1 if the object was removed, otherwise return 0. Beware, if this + * function returns 0, you still can not count on the kref from remaining in + * memory. Only use the return value if you want to see if the kref is now + * gone, not present. + */ +static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref)) +{ + return kref_sub(kref, 1, release); +} #endif /* _KREF_H_ */ |