Turn 'semadj' in 'struct sem_undo' into a flexible array.
The advantages are:
- save the size of a pointer when the new undo structure is allocated
- avoid some always ugly pointer arithmetic to get the address of semadj
- avoid an indirection when the array is accessed
While at it, use struct_size() to compute the size of the new undo
structure.
Link: https://lkml.kernel.org/r/1ba993d443ad7e16ac2b1902adab1f05ebdfa454.1688918791.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Manfred Spraul <manfred@colorfullife.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
struct list_head list_id; /* per semaphore array list:
* all undos for one array */
int semid; /* semaphore set identifier */
struct list_head list_id; /* per semaphore array list:
* all undos for one array */
int semid; /* semaphore set identifier */
- short *semadj; /* array of adjustments */
+ short semadj[]; /* array of adjustments */
/* one per semaphore */
};
/* one per semaphore */
};
rcu_read_unlock();
/* step 2: allocate new undo structure */
rcu_read_unlock();
/* step 2: allocate new undo structure */
- new = kvzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems,
- GFP_KERNEL_ACCOUNT);
+ new = kvzalloc(struct_size(new, semadj, nsems), GFP_KERNEL_ACCOUNT);
if (!new) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
return ERR_PTR(-ENOMEM);
if (!new) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
return ERR_PTR(-ENOMEM);
goto success;
}
/* step 5: initialize & link new undo structure */
goto success;
}
/* step 5: initialize & link new undo structure */
- new->semadj = (short *) &new[1];
new->ulp = ulp;
new->semid = semid;
assert_spin_locked(&ulp->lock);
new->ulp = ulp;
new->semid = semid;
assert_spin_locked(&ulp->lock);