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Commit f8dbe8d2 authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
Browse files

ipc: drop non-RCU allocation 

The only users of ipc_alloc() were ipc_rcu_alloc() and the on-heap
sem_io fall-back memory.  Better to just open-code these to make things
easier to read.

[manfred@colorfullife.com: Rediff due to inclusion of memset() into ipc_rcu_alloc()]
Link: http://lkml.kernel.org/r/20170525185107.12869-5-manfred@colorfullife.com


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2cd648c1

ipc/sem.c

+5 −3
Original line number Diff line number Diff line
@@ -1368,7 +1368,8 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, 
			}

			sem_unlock(sma, -1);

			rcu_read_unlock();

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

			sem_io = kvmalloc_array(nsems, sizeof(ushort),

						GFP_KERNEL);

			if (sem_io == NULL) {

				ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);

				return -ENOMEM;
@@ -1402,7 +1403,8 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, 
		rcu_read_unlock();



		if (nsems > SEMMSL_FAST) {

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

			sem_io = kvmalloc_array(nsems, sizeof(ushort),

						GFP_KERNEL);

			if (sem_io == NULL) {

				ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);

				return -ENOMEM;
@@ -1480,7 +1482,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, 
	wake_up_q(&wake_q);

out_free:

	if (sem_io != fast_sem_io)

		ipc_free(sem_io);

		kvfree(sem_io);

	return err;

}

ipc/util.c

+1 −24
Original line number Diff line number Diff line
@@ -394,29 +394,6 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) 
	ipcp->deleted = true;

}



/**

 * ipc_alloc -	allocate ipc space

 * @size: size desired

 *

 * Allocate memory from the appropriate pools and return a pointer to it.

 * NULL is returned if the allocation fails

 */

void *ipc_alloc(int size)

{

	return kvmalloc(size, GFP_KERNEL);

}



/**

 * ipc_free - free ipc space

 * @ptr: pointer returned by ipc_alloc

 *

 * Free a block created with ipc_alloc().

 */

void ipc_free(void *ptr)

{

	kvfree(ptr);

}



/**

 * ipc_rcu_alloc - allocate ipc space

 * @size: size desired
@@ -429,7 +406,7 @@ struct kern_ipc_perm *ipc_rcu_alloc(int size) 
	/*

	 * We prepend the allocation with the rcu struct

	 */

	struct kern_ipc_perm *out = ipc_alloc(size);

	struct kern_ipc_perm *out = kvmalloc(size, GFP_KERNEL);

	if (unlikely(!out))

		return NULL;

ipc/util.h

+0 −6
Original line number Diff line number Diff line
@@ -107,12 +107,6 @@ void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); 
/* must be called with ipcp locked */

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);



/*

 * For allocation that need to be freed by RCU.

 * Objects are reference counted, they start with reference count 1.