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Commit d9a605e4 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

ipc: rename ids->rw_mutex 



Since in some situations the lock can be shared for readers, we shouldn't
be calling it a mutex, rename it to rwsem.

Signed-off-by: default avatarDavidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c2c737a0

include/linux/ipc_namespace.h

+1 −1
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ struct ipc_ids { 
	int in_use;

	unsigned short seq;

	unsigned short seq_max;

	struct rw_semaphore rw_mutex;

	struct rw_semaphore rwsem;

	struct idr ipcs_idr;

	int next_id;

};

ipc/msg.c

+10 −10
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ 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.rw_mutex held (writer)

 * Called with msg_ids.rwsem held (writer)

 */

static int newque(struct ipc_namespace *ns, struct ipc_params *params)

{
@@ -259,8 +259,8 @@ 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.rw_mutex (writer) and the spinlock for this message queue are held

 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.

 * msg_ids.rwsem (writer) and the spinlock for this message queue are held

 * before freeque() is called. msg_ids.rwsem remains locked on exit.

 */

static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)

{
@@ -282,7 +282,7 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) 
}



/*

 * Called with msg_ids.rw_mutex and ipcp locked.

 * Called with msg_ids.rwsem and ipcp locked.

 */

static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)

{
@@ -386,9 +386,9 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) 
}



/*

 * This function handles some msgctl commands which require the rw_mutex

 * This function handles some msgctl commands which require the rwsem

 * to be held in write mode.

 * NOTE: no locks must be held, the rw_mutex is taken inside this function.

 * NOTE: no locks must be held, the rwsem is taken inside this function.

 */

static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,

		       struct msqid_ds __user *buf, int version)
@@ -403,7 +403,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, 
			return -EFAULT;

	}



	down_write(&msg_ids(ns).rw_mutex);

	down_write(&msg_ids(ns).rwsem);

	rcu_read_lock();



	ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
@@ -459,7 +459,7 @@ out_unlock0: 
out_unlock1:

	rcu_read_unlock();

out_up:

	up_write(&msg_ids(ns).rw_mutex);

	up_write(&msg_ids(ns).rwsem);

	return err;

}
@@ -494,7 +494,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid, 
		msginfo.msgmnb = ns->msg_ctlmnb;

		msginfo.msgssz = MSGSSZ;

		msginfo.msgseg = MSGSEG;

		down_read(&msg_ids(ns).rw_mutex);

		down_read(&msg_ids(ns).rwsem);

		if (cmd == MSG_INFO) {

			msginfo.msgpool = msg_ids(ns).in_use;

			msginfo.msgmap = atomic_read(&ns->msg_hdrs);
@@ -505,7 +505,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid, 
			msginfo.msgtql = MSGTQL;

		}

		max_id = ipc_get_maxid(&msg_ids(ns));

		up_read(&msg_ids(ns).rw_mutex);

		up_read(&msg_ids(ns).rwsem);

		if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))

			return -EFAULT;

		return (max_id < 0) ? 0 : max_id;

ipc/namespace.c

+2 −2
Original line number Diff line number Diff line
@@ -81,7 +81,7 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, 
	int next_id;

	int total, in_use;



	down_write(&ids->rw_mutex);

	down_write(&ids->rwsem);



	in_use = ids->in_use;
@@ -93,7 +93,7 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, 
		free(ns, perm);

		total++;

	}

	up_write(&ids->rw_mutex);

	up_write(&ids->rwsem);

}



static void free_ipc_ns(struct ipc_namespace *ns)

ipc/sem.c

+12 −12
Original line number Diff line number Diff line
@@ -322,7 +322,7 @@ static inline void sem_unlock(struct sem_array *sma, int locknum) 
}



/*

 * sem_lock_(check_) routines are called in the paths where the rw_mutex

 * sem_lock_(check_) routines are called in the paths where the rwsem

 * is not held.

 *

 * The caller holds the RCU read lock.
@@ -426,7 +426,7 @@ 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.rw_mutex held (as a writer)

 * Called with sem_ids.rwsem held (as a writer)

 */



static int newary(struct ipc_namespace *ns, struct ipc_params *params)
@@ -492,7 +492,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) 




/*

 * Called with sem_ids.rw_mutex and ipcp locked.

 * Called with sem_ids.rwsem and ipcp locked.

 */

static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)

{
@@ -503,7 +503,7 @@ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) 
}



/*

 * Called with sem_ids.rw_mutex and ipcp locked.

 * Called with sem_ids.rwsem and ipcp locked.

 */

static inline int sem_more_checks(struct kern_ipc_perm *ipcp,

				struct ipc_params *params)
@@ -994,8 +994,8 @@ static int count_semzcnt (struct sem_array * sma, ushort semnum) 
	return semzcnt;

}



/* 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

/* Free a semaphore set. freeary() is called with sem_ids.rwsem locked

 * as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem

 * remains locked on exit.

 */

static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
@@ -1116,7 +1116,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, 
		seminfo.semmnu = SEMMNU;

		seminfo.semmap = SEMMAP;

		seminfo.semume = SEMUME;

		down_read(&sem_ids(ns).rw_mutex);

		down_read(&sem_ids(ns).rwsem);

		if (cmd == SEM_INFO) {

			seminfo.semusz = sem_ids(ns).in_use;

			seminfo.semaem = ns->used_sems;
@@ -1125,7 +1125,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, 
			seminfo.semaem = SEMAEM;

		}

		max_id = ipc_get_maxid(&sem_ids(ns));

		up_read(&sem_ids(ns).rw_mutex);

		up_read(&sem_ids(ns).rwsem);

		if (copy_to_user(p, &seminfo, sizeof(struct seminfo))) 

			return -EFAULT;

		return (max_id < 0) ? 0: max_id;
@@ -1431,9 +1431,9 @@ copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version) 
}



/*

 * This function handles some semctl commands which require the rw_mutex

 * This function handles some semctl commands which require the rwsem

 * to be held in write mode.

 * NOTE: no locks must be held, the rw_mutex is taken inside this function.

 * NOTE: no locks must be held, the rwsem is taken inside this function.

 */

static int semctl_down(struct ipc_namespace *ns, int semid,

		       int cmd, int version, void __user *p)
@@ -1448,7 +1448,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid, 
			return -EFAULT;

	}



	down_write(&sem_ids(ns).rw_mutex);

	down_write(&sem_ids(ns).rwsem);

	rcu_read_lock();



	ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
@@ -1487,7 +1487,7 @@ out_unlock0: 
out_unlock1:

	rcu_read_unlock();

out_up:

	up_write(&sem_ids(ns).rw_mutex);

	up_write(&sem_ids(ns).rwsem);

	return err;

}

ipc/shm.c

+28 −28
Original line number Diff line number Diff line
@@ -83,8 +83,8 @@ void shm_init_ns(struct ipc_namespace *ns) 
}



/*

 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.

 * Only shm_ids.rw_mutex remains locked on exit.

 * Called with shm_ids.rwsem (writer) and the shp structure locked.

 * Only shm_ids.rwsem remains locked on exit.

 */

static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)

{
@@ -148,7 +148,7 @@ static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace 
}



/*

 * shm_lock_(check_) routines are called in the paths where the rw_mutex

 * shm_lock_(check_) routines are called in the paths where the rwsem

 * is not necessarily held.

 */

static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
@@ -205,7 +205,7 @@ static void shm_open(struct vm_area_struct *vma) 
 * @ns: namespace

 * @shp: struct to free

 *

 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,

 * It has to be called with shp and shm_ids.rwsem (writer) locked,

 * but returns with shp unlocked and freed.

 */

static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
@@ -253,7 +253,7 @@ static void shm_close(struct vm_area_struct *vma) 
	struct shmid_kernel *shp;

	struct ipc_namespace *ns = sfd->ns;



	down_write(&shm_ids(ns).rw_mutex);

	down_write(&shm_ids(ns).rwsem);

	/* remove from the list of attaches of the shm segment */

	shp = shm_lock(ns, sfd->id);

	BUG_ON(IS_ERR(shp));
@@ -264,10 +264,10 @@ static void shm_close(struct vm_area_struct *vma) 
		shm_destroy(ns, shp);

	else

		shm_unlock(shp);

	up_write(&shm_ids(ns).rw_mutex);

	up_write(&shm_ids(ns).rwsem);

}



/* Called with ns->shm_ids(ns).rw_mutex locked */

/* Called with ns->shm_ids(ns).rwsem locked */

static int shm_try_destroy_current(int id, void *p, void *data)

{

	struct ipc_namespace *ns = data;
@@ -298,7 +298,7 @@ static int shm_try_destroy_current(int id, void *p, void *data) 
	return 0;

}



/* Called with ns->shm_ids(ns).rw_mutex locked */

/* Called with ns->shm_ids(ns).rwsem locked */

static int shm_try_destroy_orphaned(int id, void *p, void *data)

{

	struct ipc_namespace *ns = data;
@@ -309,7 +309,7 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data) 
	 * We want to destroy segments without users and with already

	 * exit'ed originating process.

	 *

	 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.

	 * As shp->* are changed under rwsem, it's safe to skip shp locking.

	 */

	if (shp->shm_creator != NULL)

		return 0;
@@ -323,10 +323,10 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data) 


void shm_destroy_orphaned(struct ipc_namespace *ns)

{

	down_write(&shm_ids(ns).rw_mutex);

	down_write(&shm_ids(ns).rwsem);

	if (shm_ids(ns).in_use)

		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);

	up_write(&shm_ids(ns).rw_mutex);

	up_write(&shm_ids(ns).rwsem);

}
@@ -338,10 +338,10 @@ void exit_shm(struct task_struct *task) 
		return;



	/* Destroy all already created segments, but not mapped yet */

	down_write(&shm_ids(ns).rw_mutex);

	down_write(&shm_ids(ns).rwsem);

	if (shm_ids(ns).in_use)

		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);

	up_write(&shm_ids(ns).rw_mutex);

	up_write(&shm_ids(ns).rwsem);

}



static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
@@ -475,7 +475,7 @@ static const struct vm_operations_struct shm_vm_ops = { 
 * @ns: namespace

 * @params: ptr to the structure that contains key, size and shmflg

 *

 * Called with shm_ids.rw_mutex held as a writer.

 * Called with shm_ids.rwsem held as a writer.

 */



static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
@@ -583,7 +583,7 @@ no_file: 
}



/*

 * Called with shm_ids.rw_mutex and ipcp locked.

 * Called with shm_ids.rwsem and ipcp locked.

 */

static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)

{
@@ -594,7 +594,7 @@ static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) 
}



/*

 * Called with shm_ids.rw_mutex and ipcp locked.

 * Called with shm_ids.rwsem and ipcp locked.

 */

static inline int shm_more_checks(struct kern_ipc_perm *ipcp,

				struct ipc_params *params)
@@ -707,7 +707,7 @@ static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminf 


/*

 * Calculate and add used RSS and swap pages of a shm.

 * Called with shm_ids.rw_mutex held as a reader

 * Called with shm_ids.rwsem held as a reader

 */

static void shm_add_rss_swap(struct shmid_kernel *shp,

	unsigned long *rss_add, unsigned long *swp_add)
@@ -734,7 +734,7 @@ static void shm_add_rss_swap(struct shmid_kernel *shp, 
}



/*

 * Called with shm_ids.rw_mutex held as a reader

 * Called with shm_ids.rwsem held as a reader

 */

static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,

		unsigned long *swp)
@@ -763,9 +763,9 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, 
}



/*

 * This function handles some shmctl commands which require the rw_mutex

 * This function handles some shmctl commands which require the rwsem

 * to be held in write mode.

 * NOTE: no locks must be held, the rw_mutex is taken inside this function.

 * NOTE: no locks must be held, the rwsem is taken inside this function.

 */

static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,

		       struct shmid_ds __user *buf, int version)
@@ -780,7 +780,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, 
			return -EFAULT;

	}



	down_write(&shm_ids(ns).rw_mutex);

	down_write(&shm_ids(ns).rwsem);

	rcu_read_lock();



	ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
@@ -819,7 +819,7 @@ out_unlock0: 
out_unlock1:

	rcu_read_unlock();

out_up:

	up_write(&shm_ids(ns).rw_mutex);

	up_write(&shm_ids(ns).rwsem);

	return err;

}
@@ -850,9 +850,9 @@ static int shmctl_nolock(struct ipc_namespace *ns, int shmid, 
		if(copy_shminfo_to_user (buf, &shminfo, version))

			return -EFAULT;



		down_read(&shm_ids(ns).rw_mutex);

		down_read(&shm_ids(ns).rwsem);

		err = ipc_get_maxid(&shm_ids(ns));

		up_read(&shm_ids(ns).rw_mutex);

		up_read(&shm_ids(ns).rwsem);



		if(err<0)

			err = 0;
@@ -863,14 +863,14 @@ static int shmctl_nolock(struct ipc_namespace *ns, int shmid, 
		struct shm_info shm_info;



		memset(&shm_info, 0, sizeof(shm_info));

		down_read(&shm_ids(ns).rw_mutex);

		down_read(&shm_ids(ns).rwsem);

		shm_info.used_ids = shm_ids(ns).in_use;

		shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);

		shm_info.shm_tot = ns->shm_tot;

		shm_info.swap_attempts = 0;

		shm_info.swap_successes = 0;

		err = ipc_get_maxid(&shm_ids(ns));

		up_read(&shm_ids(ns).rw_mutex);

		up_read(&shm_ids(ns).rwsem);

		if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {

			err = -EFAULT;

			goto out;
@@ -1169,7 +1169,7 @@ out_fput: 
	fput(file);



out_nattch:

	down_write(&shm_ids(ns).rw_mutex);

	down_write(&shm_ids(ns).rwsem);

	shp = shm_lock(ns, shmid);

	BUG_ON(IS_ERR(shp));

	shp->shm_nattch--;
@@ -1177,7 +1177,7 @@ out_nattch: 
		shm_destroy(ns, shp);

	else

		shm_unlock(shp);

	up_write(&shm_ids(ns).rw_mutex);

	up_write(&shm_ids(ns).rwsem);

	return err;



out_unlock: