diff options
Diffstat (limited to 'ipc/util.h')
| -rw-r--r-- | ipc/util.h | 89 |
1 files changed, 58 insertions, 31 deletions
diff --git a/ipc/util.h b/ipc/util.h index eeb79a1fbd8..1a5a0fcd099 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -15,9 +15,9 @@ #define SEQ_MULTIPLIER (IPCMNI) -void sem_init (void); -void msg_init (void); -void shm_init (void); +void sem_init(void); +void msg_init(void); +void shm_init(void); struct ipc_namespace; @@ -47,6 +47,13 @@ static inline void msg_exit_ns(struct ipc_namespace *ns) { } static inline void shm_exit_ns(struct ipc_namespace *ns) { } #endif +struct ipc_rcu { + struct rcu_head rcu; + atomic_t refcount; +} ____cacheline_aligned_in_smp; + +#define ipc_rcu_to_struct(p) ((void *)(p+1)) + /* * Structure that holds the parameters needed by the ipc operations * (see after) @@ -71,9 +78,9 @@ struct ipc_params { * . routine to call for an extra check if needed */ struct ipc_ops { - int (*getnew) (struct ipc_namespace *, struct ipc_params *); - int (*associate) (struct kern_ipc_perm *, int); - int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *); + int (*getnew)(struct ipc_namespace *, struct ipc_params *); + int (*associate)(struct kern_ipc_perm *, int); + int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *); }; struct seq_file; @@ -93,11 +100,12 @@ void __init ipc_init_proc_interface(const char *path, const char *header, #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER) #define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER) +#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX) -/* must be called with ids->rw_mutex acquired for writing */ +/* must be called with ids->rwsem acquired for writing */ int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); -/* must be called with ids->rw_mutex acquired for reading */ +/* must be called with ids->rwsem acquired for reading */ int ipc_get_maxid(struct ipc_ids *); /* must be called with both locks acquired. */ @@ -109,8 +117,8 @@ int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); /* for rare, potentially huge allocations. * both function can sleep */ -void* ipc_alloc(int size); -void ipc_free(void* ptr, int size); +void *ipc_alloc(int size); +void ipc_free(void *ptr, int size); /* * For allocation that need to be freed by RCU. @@ -118,30 +126,32 @@ void ipc_free(void* ptr, int size); * getref increases the refcount, the putref call that reduces the recount * to 0 schedules the rcu destruction. Caller must guarantee locking. */ -void* ipc_rcu_alloc(int size); -void ipc_rcu_getref(void *ptr); -void ipc_rcu_putref(void *ptr); +void *ipc_rcu_alloc(int size); +int ipc_rcu_getref(void *ptr); +void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)); +void ipc_rcu_free(struct rcu_head *head); struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); +struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id); void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); -struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns, - struct ipc_ids *ids, int id, int cmd, - struct ipc64_perm *perm, int extra_perm); +struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, + struct ipc_ids *ids, int id, int cmd, + struct ipc64_perm *perm, int extra_perm); #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION - /* On IA-64, we always use the "64-bit version" of the IPC structures. */ +/* On IA-64, we always use the "64-bit version" of the IPC structures. */ # define ipc_parse_version(cmd) IPC_64 #else -int ipc_parse_version (int *cmd); +int ipc_parse_version(int *cmd); #endif extern void free_msg(struct msg_msg *msg); -extern struct msg_msg *load_msg(const void __user *src, int len); +extern struct msg_msg *load_msg(const void __user *src, size_t len); extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); -extern int store_msg(void __user *dest, struct msg_msg *msg, int len); +extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); extern void recompute_msgmni(struct ipc_namespace *); @@ -150,31 +160,48 @@ static inline int ipc_buildid(int id, int seq) return SEQ_MULTIPLIER * seq + id; } -/* - * Must be called with ipcp locked - */ static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) { - if (uid / SEQ_MULTIPLIER != ipcp->seq) - return 1; - return 0; + return uid / SEQ_MULTIPLIER != ipcp->seq; } -static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm) +static inline void ipc_lock_object(struct kern_ipc_perm *perm) { - rcu_read_lock(); spin_lock(&perm->lock); } -static inline void ipc_unlock(struct kern_ipc_perm *perm) +static inline void ipc_unlock_object(struct kern_ipc_perm *perm) { spin_unlock(&perm->lock); +} + +static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) +{ + assert_spin_locked(&perm->lock); +} + +static inline void ipc_unlock(struct kern_ipc_perm *perm) +{ + ipc_unlock_object(perm); rcu_read_unlock(); } -struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id); +/* + * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths + * where the respective ipc_ids.rwsem is not being held down. + * Checks whether the ipc object is still around or if it's gone already, as + * ipc_rmid() may have already freed the ID while the ipc lock was spinning. + * Needs to be called with kern_ipc_perm.lock held -- exception made for one + * checkpoint case at sys_semtimedop() as noted in code commentary. + */ +static inline bool ipc_valid_object(struct kern_ipc_perm *perm) +{ + return !perm->deleted; +} + +struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, - struct ipc_ops *ops, struct ipc_params *params); + const struct ipc_ops *ops, struct ipc_params *params); void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); #endif |