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Commit 6ff37972 authored by Pierre Peiffer's avatar Pierre Peiffer Committed by Linus Torvalds
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IPC/semaphores: code factorisation 



Trivial patch which adds some small locking functions and makes use of them to
factorize some part of the code and to make it cleaner.

Signed-off-by: default avatarPierre Peiffer <pierre.peiffer@bull.net>
Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6546bc42

ipc/sem.c

+31 −30
Original line number Diff line number Diff line
@@ -180,6 +180,25 @@ static inline struct sem_array *sem_lock_check(struct ipc_namespace *ns, 
	return container_of(ipcp, struct sem_array, sem_perm);

}



static inline void sem_lock_and_putref(struct sem_array *sma)

{

	ipc_lock_by_ptr(&sma->sem_perm);

	ipc_rcu_putref(sma);

}



static inline void sem_getref_and_unlock(struct sem_array *sma)

{

	ipc_rcu_getref(sma);

	ipc_unlock(&(sma)->sem_perm);

}



static inline void sem_putref(struct sem_array *sma)

{

	ipc_lock_by_ptr(&sma->sem_perm);

	ipc_rcu_putref(sma);

	ipc_unlock(&(sma)->sem_perm);

}



static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)

{

	ipc_rmid(&sem_ids(ns), &s->sem_perm);
@@ -698,19 +717,15 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, 
		int i;



		if(nsems > SEMMSL_FAST) {

			ipc_rcu_getref(sma);

			sem_unlock(sma);			

			sem_getref_and_unlock(sma);



			sem_io = ipc_alloc(sizeof(ushort)*nsems);

			if(sem_io == NULL) {

				ipc_lock_by_ptr(&sma->sem_perm);

				ipc_rcu_putref(sma);

				sem_unlock(sma);

				sem_putref(sma);

				return -ENOMEM;

			}



			ipc_lock_by_ptr(&sma->sem_perm);

			ipc_rcu_putref(sma);

			sem_lock_and_putref(sma);

			if (sma->sem_perm.deleted) {

				sem_unlock(sma);

				err = -EIDRM;
@@ -731,38 +746,30 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, 
		int i;

		struct sem_undo *un;



		ipc_rcu_getref(sma);

		sem_unlock(sma);

		sem_getref_and_unlock(sma);



		if(nsems > SEMMSL_FAST) {

			sem_io = ipc_alloc(sizeof(ushort)*nsems);

			if(sem_io == NULL) {

				ipc_lock_by_ptr(&sma->sem_perm);

				ipc_rcu_putref(sma);

				sem_unlock(sma);

				sem_putref(sma);

				return -ENOMEM;

			}

		}



		if (copy_from_user (sem_io, arg.array, nsems*sizeof(ushort))) {

			ipc_lock_by_ptr(&sma->sem_perm);

			ipc_rcu_putref(sma);

			sem_unlock(sma);

			sem_putref(sma);

			err = -EFAULT;

			goto out_free;

		}



		for (i = 0; i < nsems; i++) {

			if (sem_io[i] > SEMVMX) {

				ipc_lock_by_ptr(&sma->sem_perm);

				ipc_rcu_putref(sma);

				sem_unlock(sma);

				sem_putref(sma);

				err = -ERANGE;

				goto out_free;

			}

		}

		ipc_lock_by_ptr(&sma->sem_perm);

		ipc_rcu_putref(sma);

		sem_lock_and_putref(sma);

		if (sma->sem_perm.deleted) {

			sem_unlock(sma);

			err = -EIDRM;
@@ -1042,14 +1049,11 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid) 
		return ERR_PTR(PTR_ERR(sma));



	nsems = sma->sem_nsems;

	ipc_rcu_getref(sma);

	sem_unlock(sma);

	sem_getref_and_unlock(sma);



	new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);

	if (!new) {

		ipc_lock_by_ptr(&sma->sem_perm);

		ipc_rcu_putref(sma);

		sem_unlock(sma);

		sem_putref(sma);

		return ERR_PTR(-ENOMEM);

	}

	new->semadj = (short *) &new[1];
@@ -1060,13 +1064,10 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid) 
	if (un) {

		spin_unlock(&ulp->lock);

		kfree(new);

		ipc_lock_by_ptr(&sma->sem_perm);

		ipc_rcu_putref(sma);

		sem_unlock(sma);

		sem_putref(sma);

		goto out;

	}

	ipc_lock_by_ptr(&sma->sem_perm);

	ipc_rcu_putref(sma);

	sem_lock_and_putref(sma);

	if (sma->sem_perm.deleted) {

		sem_unlock(sma);

		spin_unlock(&ulp->lock);