diff options
Diffstat (limited to 'ipc/sem.c')
| -rw-r--r-- | ipc/sem.c | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index 45c7e573c20..019e21332dd 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -80,7 +80,7 @@ #include <linux/audit.h> #include <linux/capability.h> #include <linux/seq_file.h> -#include <linux/mutex.h> +#include <linux/rwsem.h> #include <linux/nsproxy.h> #include <asm/uaccess.h> @@ -148,7 +148,7 @@ void sem_exit_ns(struct ipc_namespace *ns) int next_id; int total, in_use; - mutex_lock(&sem_ids(ns).mutex); + down_write(&sem_ids(ns).rw_mutex); in_use = sem_ids(ns).in_use; @@ -160,7 +160,7 @@ void sem_exit_ns(struct ipc_namespace *ns) freeary(ns, sma); total++; } - mutex_unlock(&sem_ids(ns).mutex); + up_write(&sem_ids(ns).rw_mutex); kfree(ns->ids[IPC_SEM_IDS]); ns->ids[IPC_SEM_IDS] = NULL; @@ -174,6 +174,22 @@ void __init sem_init (void) IPC_SEM_IDS, sysvipc_sem_proc_show); } +/* + * This routine is called in the paths where the rw_mutex is held to protect + * access to the idr tree. + */ +static inline struct sem_array *sem_lock_check_down(struct ipc_namespace *ns, + int id) +{ + struct kern_ipc_perm *ipcp = ipc_lock_check_down(&sem_ids(ns), id); + + return container_of(ipcp, struct sem_array, sem_perm); +} + +/* + * sem_lock_(check_) routines are called in the paths where the rw_mutex + * is not held. + */ static inline struct sem_array *sem_lock(struct ipc_namespace *ns, int id) { struct kern_ipc_perm *ipcp = ipc_lock(&sem_ids(ns), id); @@ -233,7 +249,7 @@ static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) * @ns: namespace * @params: ptr to the structure that contains key, semflg and nsems * - * Called with sem_ids.mutex held + * Called with sem_ids.rw_mutex held (as a writer) */ static int newary(struct ipc_namespace *ns, struct ipc_params *params) @@ -290,7 +306,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) /* - * Called with sem_ids.mutex and ipcp locked. + * Called with sem_ids.rw_mutex and ipcp locked. */ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) { @@ -301,7 +317,7 @@ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) } /* - * Called with sem_ids.mutex and ipcp locked. + * Called with sem_ids.rw_mutex and ipcp locked. */ static inline int sem_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params) @@ -528,9 +544,9 @@ static int count_semzcnt (struct sem_array * sma, ushort semnum) return semzcnt; } -/* Free a semaphore set. freeary() is called with sem_ids.mutex locked and - * the spinlock for this semaphore set hold. sem_ids.mutex remains locked - * on exit. +/* Free a semaphore set. freeary() is called with sem_ids.rw_mutex locked + * as a writer and the spinlock for this semaphore set hold. sem_ids.rw_mutex + * remains locked on exit. */ static void freeary(struct ipc_namespace *ns, struct sem_array *sma) { @@ -615,7 +631,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum, seminfo.semmnu = SEMMNU; seminfo.semmap = SEMMAP; seminfo.semume = SEMUME; - mutex_lock(&sem_ids(ns).mutex); + down_read(&sem_ids(ns).rw_mutex); if (cmd == SEM_INFO) { seminfo.semusz = sem_ids(ns).in_use; seminfo.semaem = ns->used_sems; @@ -624,7 +640,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum, seminfo.semaem = SEMAEM; } max_id = ipc_get_maxid(&sem_ids(ns)); - mutex_unlock(&sem_ids(ns).mutex); + up_read(&sem_ids(ns).rw_mutex); if (copy_to_user (arg.__buf, &seminfo, sizeof(struct seminfo))) return -EFAULT; return (max_id < 0) ? 0: max_id; @@ -895,7 +911,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid, int semnum, if(copy_semid_from_user (&setbuf, arg.buf, version)) return -EFAULT; } - sma = sem_lock_check(ns, semid); + sma = sem_lock_check_down(ns, semid); if (IS_ERR(sma)) return PTR_ERR(sma); @@ -976,9 +992,9 @@ asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg) return err; case IPC_RMID: case IPC_SET: - mutex_lock(&sem_ids(ns).mutex); + down_write(&sem_ids(ns).rw_mutex); err = semctl_down(ns,semid,semnum,cmd,version,arg); - mutex_unlock(&sem_ids(ns).mutex); + up_write(&sem_ids(ns).rw_mutex); return err; default: return -EINVAL; |