X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=ipc%2Fmsg.c;h=fdf3db5731ce8df2cfd038f40c69710243d85338;hb=7607341a265a56cdf8b4bf10d355098e80ea481b;hp=b7274dbf0917f3c1da7efdd10d6b2d8e6ada80fb;hpb=f4566f04854d78acfc74b9acb029744acde9d033;p=linux-2.6 diff --git a/ipc/msg.c b/ipc/msg.c index b7274dbf09..fdf3db5731 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -34,7 +34,7 @@ #include #include #include -#include +#include #include #include @@ -66,16 +66,12 @@ struct msg_sender { #define SEARCH_NOTEQUAL 3 #define SEARCH_LESSEQUAL 4 -static atomic_t msg_bytes = ATOMIC_INIT(0); -static atomic_t msg_hdrs = ATOMIC_INIT(0); - static struct ipc_ids init_msg_ids; #define msg_ids(ns) (*((ns)->ids[IPC_MSG_IDS])) #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) -#define msg_buildid(ns, id, seq) \ - ipc_buildid(&msg_ids(ns), id, seq) +#define msg_buildid(id, seq) ipc_buildid(id, seq) static void freeque(struct ipc_namespace *, struct msg_queue *); static int newque(struct ipc_namespace *, struct ipc_params *); @@ -89,6 +85,8 @@ static void __msg_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids) ns->msg_ctlmax = MSGMAX; ns->msg_ctlmnb = MSGMNB; ns->msg_ctlmni = MSGMNI; + atomic_set(&ns->msg_bytes, 0); + atomic_set(&ns->msg_hdrs, 0); ipc_init_ids(ids); } @@ -110,7 +108,7 @@ void msg_exit_ns(struct ipc_namespace *ns) int next_id; int total, in_use; - mutex_lock(&msg_ids(ns).mutex); + down_write(&msg_ids(ns).rw_mutex); in_use = msg_ids(ns).in_use; @@ -122,7 +120,8 @@ void msg_exit_ns(struct ipc_namespace *ns) freeque(ns, msq); total++; } - mutex_unlock(&msg_ids(ns).mutex); + + up_write(&msg_ids(ns).rw_mutex); kfree(ns->ids[IPC_MSG_IDS]); ns->ids[IPC_MSG_IDS] = NULL; @@ -136,6 +135,22 @@ void __init msg_init(void) IPC_MSG_IDS, sysvipc_msg_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 msg_queue *msg_lock_check_down(struct ipc_namespace *ns, + int id) +{ + struct kern_ipc_perm *ipcp = ipc_lock_check_down(&msg_ids(ns), id); + + return container_of(ipcp, struct msg_queue, q_perm); +} + +/* + * msg_lock_(check_) routines are called in the paths where the rw_mutex + * is not held. + */ static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id) { struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id); @@ -161,7 +176,7 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) * @ns: namespace * @params: ptr to the structure that contains the key and msgflg * - * Called with msg_ids.mutex held + * Called with msg_ids.rw_mutex held (writer) */ static int newque(struct ipc_namespace *ns, struct ipc_params *params) { @@ -188,13 +203,13 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params) * ipc_addid() locks msq */ id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); - if (id == -1) { + if (id < 0) { security_msg_queue_free(msq); ipc_rcu_putref(msq); - return -ENOSPC; + return id; } - msq->q_perm.id = msg_buildid(ns, id, msq->q_perm.seq); + msq->q_perm.id = msg_buildid(id, msq->q_perm.seq); msq->q_stime = msq->q_rtime = 0; msq->q_ctime = get_seconds(); msq->q_cbytes = msq->q_qnum = 0; @@ -260,8 +275,8 @@ static void expunge_all(struct msg_queue *msq, int res) * removes the message queue from message queue ID IDR, and cleans up all the * messages associated with this queue. * - * msg_ids.mutex and the spinlock for this message queue are held - * before freeque() is called. msg_ids.mutex remains locked on exit. + * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held + * before freeque() is called. msg_ids.rw_mutex remains locked on exit. */ static void freeque(struct ipc_namespace *ns, struct msg_queue *msq) { @@ -277,16 +292,16 @@ static void freeque(struct ipc_namespace *ns, struct msg_queue *msq) struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list); tmp = tmp->next; - atomic_dec(&msg_hdrs); + atomic_dec(&ns->msg_hdrs); free_msg(msg); } - atomic_sub(msq->q_cbytes, &msg_bytes); + atomic_sub(msq->q_cbytes, &ns->msg_bytes); security_msg_queue_free(msq); ipc_rcu_putref(msq); } /* - * Called with msg_ids.mutex and ipcp locked. + * Called with msg_ids.rw_mutex and ipcp locked. */ static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) { @@ -444,18 +459,18 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) msginfo.msgmnb = ns->msg_ctlmnb; msginfo.msgssz = MSGSSZ; msginfo.msgseg = MSGSEG; - mutex_lock(&msg_ids(ns).mutex); + down_read(&msg_ids(ns).rw_mutex); if (cmd == MSG_INFO) { msginfo.msgpool = msg_ids(ns).in_use; - msginfo.msgmap = atomic_read(&msg_hdrs); - msginfo.msgtql = atomic_read(&msg_bytes); + msginfo.msgmap = atomic_read(&ns->msg_hdrs); + msginfo.msgtql = atomic_read(&ns->msg_bytes); } else { msginfo.msgmap = MSGMAP; msginfo.msgpool = MSGPOOL; msginfo.msgtql = MSGTQL; } max_id = ipc_get_maxid(&msg_ids(ns)); - mutex_unlock(&msg_ids(ns).mutex); + up_read(&msg_ids(ns).rw_mutex); if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) return -EFAULT; return (max_id < 0) ? 0 : max_id; @@ -516,8 +531,8 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) return -EINVAL; } - mutex_lock(&msg_ids(ns).mutex); - msq = msg_lock_check(ns, msqid); + down_write(&msg_ids(ns).rw_mutex); + msq = msg_lock_check_down(ns, msqid); if (IS_ERR(msq)) { err = PTR_ERR(msq); goto out_up; @@ -576,7 +591,7 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) } err = 0; out_up: - mutex_unlock(&msg_ids(ns).mutex); + up_write(&msg_ids(ns).rw_mutex); return err; out_unlock_up: msg_unlock(msq); @@ -719,8 +734,8 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext, list_add_tail(&msg->m_list, &msq->q_messages); msq->q_cbytes += msgsz; msq->q_qnum++; - atomic_add(msgsz, &msg_bytes); - atomic_inc(&msg_hdrs); + atomic_add(msgsz, &ns->msg_bytes); + atomic_inc(&ns->msg_hdrs); } err = 0; @@ -824,8 +839,8 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext, msq->q_rtime = get_seconds(); msq->q_lrpid = task_tgid_vnr(current); msq->q_cbytes -= msg->m_ts; - atomic_sub(msg->m_ts, &msg_bytes); - atomic_dec(&msg_hdrs); + atomic_sub(msg->m_ts, &ns->msg_bytes); + atomic_dec(&ns->msg_hdrs); ss_wakeup(&msq->q_senders, 0); msg_unlock(msq); break;