diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/dcache.h | 20 | ||||
| -rw-r--r-- | include/linux/lockref.h | 71 | ||||
| -rw-r--r-- | include/linux/nsproxy.h | 6 | ||||
| -rw-r--r-- | include/linux/regmap.h | 1 | ||||
| -rw-r--r-- | include/linux/wait.h | 57 |
5 files changed, 144 insertions, 11 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index b90337c9d468..efdc94434c30 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -9,6 +9,7 @@ #include <linux/seqlock.h> #include <linux/cache.h> #include <linux/rcupdate.h> +#include <linux/lockref.h> struct nameidata; struct path; @@ -100,6 +101,8 @@ extern unsigned int full_name_hash(const unsigned char *, unsigned int); # endif #endif +#define d_lock d_lockref.lock + struct dentry { /* RCU lookup touched fields */ unsigned int d_flags; /* protected by d_lock */ @@ -112,8 +115,7 @@ struct dentry { unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ /* Ref lookup also touches following */ - unsigned int d_count; /* protected by d_lock */ - spinlock_t d_lock; /* per dentry lock */ + struct lockref d_lockref; /* per-dentry lock and refcount */ const struct dentry_operations *d_op; struct super_block *d_sb; /* The root of the dentry tree */ unsigned long d_time; /* used by d_revalidate */ @@ -318,7 +320,7 @@ static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq) assert_spin_locked(&dentry->d_lock); if (!read_seqcount_retry(&dentry->d_seq, seq)) { ret = 1; - dentry->d_count++; + dentry->d_lockref.count++; } return ret; @@ -326,7 +328,7 @@ static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq) static inline unsigned d_count(const struct dentry *dentry) { - return dentry->d_count; + return dentry->d_lockref.count; } /* validate "insecure" dentry pointer */ @@ -336,6 +338,7 @@ extern int d_validate(struct dentry *, struct dentry *); * helper function for dentry_operations.d_dname() members */ extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...); +extern char *simple_dname(struct dentry *, char *, int); extern char *__d_path(const struct path *, const struct path *, char *, int); extern char *d_absolute_path(const struct path *, char *, int); @@ -356,17 +359,14 @@ extern char *dentry_path(struct dentry *, char *, int); static inline struct dentry *dget_dlock(struct dentry *dentry) { if (dentry) - dentry->d_count++; + dentry->d_lockref.count++; return dentry; } static inline struct dentry *dget(struct dentry *dentry) { - if (dentry) { - spin_lock(&dentry->d_lock); - dget_dlock(dentry); - spin_unlock(&dentry->d_lock); - } + if (dentry) + lockref_get(&dentry->d_lockref); return dentry; } diff --git a/include/linux/lockref.h b/include/linux/lockref.h new file mode 100644 index 000000000000..01233e01627a --- /dev/null +++ b/include/linux/lockref.h @@ -0,0 +1,71 @@ +#ifndef __LINUX_LOCKREF_H +#define __LINUX_LOCKREF_H + +/* + * Locked reference counts. + * + * These are different from just plain atomic refcounts in that they + * are atomic with respect to the spinlock that goes with them. In + * particular, there can be implementations that don't actually get + * the spinlock for the common decrement/increment operations, but they + * still have to check that the operation is done semantically as if + * the spinlock had been taken (using a cmpxchg operation that covers + * both the lock and the count word, or using memory transactions, for + * example). + */ + +#include <linux/spinlock.h> + +struct lockref { + spinlock_t lock; + unsigned int count; +}; + +/** + * 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. + */ +static inline void lockref_get(struct lockref *lockref) +{ + spin_lock(&lockref->lock); + lockref->count++; + spin_unlock(&lockref->lock); +} + +/** + * 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 is 0 + */ +static inline int lockref_get_not_zero(struct lockref *lockref) +{ + int retval = 0; + + spin_lock(&lockref->lock); + if (lockref->count) { + lockref->count++; + retval = 1; + } + spin_unlock(&lockref->lock); + return retval; +} + +/** + * 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 + */ +static inline int lockref_put_or_lock(struct lockref *lockref) +{ + spin_lock(&lockref->lock); + if (lockref->count <= 1) + return 0; + lockref->count--; + spin_unlock(&lockref->lock); + return 1; +} + +#endif /* __LINUX_LOCKREF_H */ diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h index 10e5947491c7..b4ec59d159ac 100644 --- a/include/linux/nsproxy.h +++ b/include/linux/nsproxy.h @@ -14,6 +14,10 @@ struct fs_struct; * A structure to contain pointers to all per-process * namespaces - fs (mount), uts, network, sysvipc, etc. * + * The pid namespace is an exception -- it's accessed using + * task_active_pid_ns. The pid namespace here is the + * namespace that children will use. + * * 'count' is the number of tasks holding a reference. * The count for each namespace, then, will be the number * of nsproxies pointing to it, not the number of tasks. @@ -27,7 +31,7 @@ struct nsproxy { struct uts_namespace *uts_ns; struct ipc_namespace *ipc_ns; struct mnt_namespace *mnt_ns; - struct pid_namespace *pid_ns; + struct pid_namespace *pid_ns_for_children; struct net *net_ns; }; extern struct nsproxy init_nsproxy; diff --git a/include/linux/regmap.h b/include/linux/regmap.h index 580a5320cc96..6d91fcb4c5cb 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -16,6 +16,7 @@ #include <linux/list.h> #include <linux/rbtree.h> #include <linux/err.h> +#include <linux/bug.h> struct module; struct device; diff --git a/include/linux/wait.h b/include/linux/wait.h index f487a4750b7f..a67fc1635592 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -811,6 +811,63 @@ do { \ __ret; \ }) +#define __wait_event_interruptible_lock_irq_timeout(wq, condition, \ + lock, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (signal_pending(current)) { \ + ret = -ERESTARTSYS; \ + break; \ + } \ + spin_unlock_irq(&lock); \ + ret = schedule_timeout(ret); \ + spin_lock_irq(&lock); \ + if (!ret) \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + +/** + * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses. + * The condition is checked under the lock. This is expected + * to be called with the lock taken. + * @wq: the waitqueue to wait on + * @condition: a C expression for the event to wait for + * @lock: a locked spinlock_t, which will be released before schedule() + * and reacquired afterwards. + * @timeout: timeout, in jiffies + * + * The process is put to sleep (TASK_INTERRUPTIBLE) until the + * @condition evaluates to true or signal is received. The @condition is + * checked each time the waitqueue @wq is woken up. + * + * wake_up() has to be called after changing any variable that could + * change the result of the wait condition. + * + * This is supposed to be called while holding the lock. The lock is + * dropped before going to sleep and is reacquired afterwards. + * + * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it + * was interrupted by a signal, and the remaining jiffies otherwise + * if the condition evaluated to true before the timeout elapsed. + */ +#define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \ + timeout) \ +({ \ + int __ret = timeout; \ + \ + if (!(condition)) \ + __wait_event_interruptible_lock_irq_timeout( \ + wq, condition, lock, __ret); \ + __ret; \ +}) + /* * These are the old interfaces to sleep waiting for an event. |