diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig | 10 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 19 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/dynamic_debug.c | 2 | ||||
| -rw-r--r-- | lib/earlycpio.c | 27 | ||||
| -rw-r--r-- | lib/kobject.c | 22 | ||||
| -rw-r--r-- | lib/lockref.c | 128 |
7 files changed, 192 insertions, 17 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 71d9f81f6eed..65561716c16c 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -48,6 +48,16 @@ config STMP_DEVICE config PERCPU_RWSEM boolean +config ARCH_USE_CMPXCHG_LOCKREF + bool + +config CMPXCHG_LOCKREF + def_bool y if ARCH_USE_CMPXCHG_LOCKREF + depends on SMP + depends on !GENERIC_LOCKBREAK + depends on !DEBUG_SPINLOCK + depends on !DEBUG_LOCK_ALLOC + config CRC_CCITT tristate "CRC-CCITT functions" help diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 1501aa553221..444e1c12fea9 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -981,6 +981,25 @@ config DEBUG_KOBJECT If you say Y here, some extra kobject debugging messages will be sent to the syslog. +config DEBUG_KOBJECT_RELEASE + bool "kobject release debugging" + depends on DEBUG_KERNEL + help + kobjects are reference counted objects. This means that their + last reference count put is not predictable, and the kobject can + live on past the point at which a driver decides to drop it's + initial reference to the kobject gained on allocation. An + example of this would be a struct device which has just been + unregistered. + + However, some buggy drivers assume that after such an operation, + the memory backing the kobject can be immediately freed. This + goes completely against the principles of a refcounted object. + + If you say Y here, the kernel will delay the release of kobjects + on the last reference count to improve the visibility of this + kind of kobject release bug. + config HAVE_DEBUG_BUGVERBOSE bool diff --git a/lib/Makefile b/lib/Makefile index 7baccfd8a4e9..f2cb3082697c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -20,6 +20,7 @@ lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o lib-y += kobject.o klist.o +obj-y += lockref.o obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \ diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 99fec3ae405a..c37aeacd7651 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -309,7 +309,7 @@ static int ddebug_parse_query(char *words[], int nwords, struct ddebug_query *query, const char *modname) { unsigned int i; - int rc; + int rc = 0; /* check we have an even number of words */ if (nwords % 2 != 0) { diff --git a/lib/earlycpio.c b/lib/earlycpio.c index 7aa7ce250c94..3eb3e4722b8e 100644 --- a/lib/earlycpio.c +++ b/lib/earlycpio.c @@ -49,22 +49,23 @@ enum cpio_fields { /** * cpio_data find_cpio_data - Search for files in an uncompressed cpio - * @path: The directory to search for, including a slash at the end - * @data: Pointer to the the cpio archive or a header inside - * @len: Remaining length of the cpio based on data pointer - * @offset: When a matching file is found, this is the offset to the - * beginning of the cpio. It can be used to iterate through - * the cpio to find all files inside of a directory path + * @path: The directory to search for, including a slash at the end + * @data: Pointer to the the cpio archive or a header inside + * @len: Remaining length of the cpio based on data pointer + * @nextoff: When a matching file is found, this is the offset from the + * beginning of the cpio to the beginning of the next file, not the + * matching file itself. It can be used to iterate through the cpio + * to find all files inside of a directory path. * - * @return: struct cpio_data containing the address, length and - * filename (with the directory path cut off) of the found file. - * If you search for a filename and not for files in a directory, - * pass the absolute path of the filename in the cpio and make sure - * the match returned an empty filename string. + * @return: struct cpio_data containing the address, length and + * filename (with the directory path cut off) of the found file. + * If you search for a filename and not for files in a directory, + * pass the absolute path of the filename in the cpio and make sure + * the match returned an empty filename string. */ struct cpio_data find_cpio_data(const char *path, void *data, - size_t len, long *offset) + size_t len, long *nextoff) { const size_t cpio_header_len = 8*C_NFIELDS - 2; struct cpio_data cd = { NULL, 0, "" }; @@ -124,7 +125,7 @@ struct cpio_data find_cpio_data(const char *path, void *data, if ((ch[C_MODE] & 0170000) == 0100000 && ch[C_NAMESIZE] >= mypathsize && !memcmp(p, path, mypathsize)) { - *offset = (long)nptr - (long)data; + *nextoff = (long)nptr - (long)data; if (ch[C_NAMESIZE] - mypathsize >= MAX_CPIO_FILE_NAME) { pr_warn( "File %s exceeding MAX_CPIO_FILE_NAME [%d]\n", diff --git a/lib/kobject.c b/lib/kobject.c index 4a1f33d43548..1d46c151a4ae 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -545,8 +545,8 @@ static void kobject_cleanup(struct kobject *kobj) struct kobj_type *t = get_ktype(kobj); const char *name = kobj->name; - pr_debug("kobject: '%s' (%p): %s\n", - kobject_name(kobj), kobj, __func__); + pr_debug("kobject: '%s' (%p): %s, parent %p\n", + kobject_name(kobj), kobj, __func__, kobj->parent); if (t && !t->release) pr_debug("kobject: '%s' (%p): does not have a release() " @@ -580,9 +580,25 @@ static void kobject_cleanup(struct kobject *kobj) } } +#ifdef CONFIG_DEBUG_KOBJECT_RELEASE +static void kobject_delayed_cleanup(struct work_struct *work) +{ + kobject_cleanup(container_of(to_delayed_work(work), + struct kobject, release)); +} +#endif + static void kobject_release(struct kref *kref) { - kobject_cleanup(container_of(kref, struct kobject, kref)); + struct kobject *kobj = container_of(kref, struct kobject, kref); +#ifdef CONFIG_DEBUG_KOBJECT_RELEASE + pr_debug("kobject: '%s' (%p): %s, parent %p (delayed)\n", + kobject_name(kobj), kobj, __func__, kobj->parent); + INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup); + schedule_delayed_work(&kobj->release, HZ); +#else + kobject_cleanup(kobj); +#endif } /** diff --git a/lib/lockref.c b/lib/lockref.c new file mode 100644 index 000000000000..9d76f404ce9a --- /dev/null +++ b/lib/lockref.c @@ -0,0 +1,128 @@ +#include <linux/export.h> +#include <linux/lockref.h> + +#ifdef CONFIG_CMPXCHG_LOCKREF + +/* + * Note that the "cmpxchg()" reloads the "old" value for the + * failure case. + */ +#define CMPXCHG_LOOP(CODE, SUCCESS) do { \ + struct lockref old; \ + BUILD_BUG_ON(sizeof(old) != 8); \ + old.lock_count = ACCESS_ONCE(lockref->lock_count); \ + while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) { \ + struct lockref new = old, prev = old; \ + CODE \ + old.lock_count = cmpxchg(&lockref->lock_count, \ + old.lock_count, new.lock_count); \ + if (likely(old.lock_count == prev.lock_count)) { \ + SUCCESS; \ + } \ + cpu_relax(); \ + } \ +} while (0) + +#else + +#define CMPXCHG_LOOP(CODE, SUCCESS) do { } while (0) + +#endif + +/** + * lockref_get - Increments reference count unconditionally + * @lockcnt: pointer to lockref structure + * + * This operation is only valid if you already hold a reference + * to the object, so you know the count cannot be zero. + */ +void lockref_get(struct lockref *lockref) +{ + CMPXCHG_LOOP( + new.count++; + , + return; + ); + + spin_lock(&lockref->lock); + lockref->count++; + spin_unlock(&lockref->lock); +} +EXPORT_SYMBOL(lockref_get); + +/** + * lockref_get_not_zero - Increments count unless the count is 0 + * @lockcnt: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if count was zero + */ +int lockref_get_not_zero(struct lockref *lockref) +{ + int retval; + + CMPXCHG_LOOP( + new.count++; + if (!old.count) + return 0; + , + return 1; + ); + + spin_lock(&lockref->lock); + retval = 0; + if (lockref->count) { + lockref->count++; + retval = 1; + } + spin_unlock(&lockref->lock); + return retval; +} +EXPORT_SYMBOL(lockref_get_not_zero); + +/** + * lockref_get_or_lock - Increments count unless the count is 0 + * @lockcnt: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if count was zero + * and we got the lock instead. + */ +int lockref_get_or_lock(struct lockref *lockref) +{ + CMPXCHG_LOOP( + new.count++; + if (!old.count) + break; + , + return 1; + ); + + spin_lock(&lockref->lock); + if (!lockref->count) + return 0; + lockref->count++; + spin_unlock(&lockref->lock); + return 1; +} +EXPORT_SYMBOL(lockref_get_or_lock); + +/** + * lockref_put_or_lock - decrements count unless count <= 1 before decrement + * @lockcnt: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if count <= 1 and lock taken + */ +int lockref_put_or_lock(struct lockref *lockref) +{ + CMPXCHG_LOOP( + new.count--; + if (old.count <= 1) + break; + , + return 1; + ); + + spin_lock(&lockref->lock); + if (lockref->count <= 1) + return 0; + lockref->count--; + spin_unlock(&lockref->lock); + return 1; +} +EXPORT_SYMBOL(lockref_put_or_lock); |