[PATCH 04/20] ipc: Drop non-RCU allocation

From: Manfred Spraul
Date: Thu May 25 2017 - 14:55:58 EST


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.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

[manfred@xxxxxxxxxxxxxxxx: Rediff due to inclusion of memset() into
ipc_rcu_alloc().]

Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
---
ipc/sem.c | 8 +++++---
ipc/util.c | 27 +++------------------------
ipc/util.h | 6 ------
3 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/ipc/sem.c b/ipc/sem.c
index bdff6d9..484ccf8 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -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;
}

diff --git a/ipc/util.c b/ipc/util.c
index 9dcc08b..dd73feb 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -395,29 +395,6 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
}

/**
- * 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
*
@@ -429,9 +406,11 @@ 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;
+
+ memset(out, 0, size);
atomic_set(&out->refcount, 1);
return out;
}
diff --git a/ipc/util.h b/ipc/util.h
index 09d0f91..2578fd9 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -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.
--
2.9.3