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Commit 8eb703e4 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Ingo Molnar
Browse files

uids: merge multiple error paths in alloc_uid() into one 



There are already 4 error paths in alloc_uid() that do incremental rollbacks.
I think it's time to merge them.  This costs us 8 lines of code :)

Maybe it would be better to merge this patch with the previous one, but I
remember that some time ago I sent a similar patch (fixing the error path and
cleaning it), but I was told to make two patches in such cases.

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent dc938520

kernel/user.c

+20 −27
Original line number Diff line number Diff line
@@ -319,7 +319,7 @@ void free_uid(struct user_struct *up) 
struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)

{

	struct hlist_head *hashent = uidhashentry(ns, uid);

	struct user_struct *up;

	struct user_struct *up, *new;



	/* Make uid_hash_find() + uids_user_create() + uid_hash_insert()

	 * atomic.
@@ -331,13 +331,9 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) 
	spin_unlock_irq(&uidhash_lock);



	if (!up) {

		struct user_struct *new;



		new = kmem_cache_alloc(uid_cachep, GFP_KERNEL);

		if (!new) {

			uids_mutex_unlock();

			return NULL;

		}

		if (!new)

			goto out_unlock;



		new->uid = uid;

		atomic_set(&new->__count, 1);
@@ -353,28 +349,14 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) 
#endif

		new->locked_shm = 0;



		if (alloc_uid_keyring(new, current) < 0) {

			kmem_cache_free(uid_cachep, new);

			uids_mutex_unlock();

			return NULL;

		}

		if (alloc_uid_keyring(new, current) < 0)

			goto out_free_user;



		if (sched_create_user(new) < 0) {

			key_put(new->uid_keyring);

			key_put(new->session_keyring);

			kmem_cache_free(uid_cachep, new);

			uids_mutex_unlock();

			return NULL;

		}

		if (sched_create_user(new) < 0)

			goto out_put_keys;



		if (uids_user_create(new)) {

			sched_destroy_user(new);

			key_put(new->uid_keyring);

			key_put(new->session_keyring);

			kmem_cache_free(uid_cachep, new);

			uids_mutex_unlock();

			return NULL;

		}

		if (uids_user_create(new))

			goto out_destoy_sched;



		/*

		 * Before adding this, check whether we raced
@@ -402,6 +384,17 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) 
	uids_mutex_unlock();



	return up;



out_destoy_sched:

	sched_destroy_user(new);

out_put_keys:

	key_put(new->uid_keyring);

	key_put(new->session_keyring);

out_free_user:

	kmem_cache_free(uid_cachep, new);

out_unlock:

	uids_mutex_unlock();

	return NULL;

}



void switch_uid(struct user_struct *new_user)