Commit 488ef356 authored by Herbert Xu's avatar Herbert Xu Committed by Linus Torvalds
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KEYS: Invert FINAL_PUT bit 



Invert the FINAL_PUT bit so that test_bit_acquire and clear_bit_unlock
can be used instead of smp_mb.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aef17cb3

include/linux/key.h

+1 −1
Original line number Diff line number Diff line
@@ -236,7 +236,7 @@ struct key { 
#define KEY_FLAG_ROOT_CAN_INVAL	7	/* set if key can be invalidated by root without permission */

#define KEY_FLAG_KEEP		8	/* set if key should not be removed */

#define KEY_FLAG_UID_KEYRING	9	/* set if key is a user or user session keyring */

#define KEY_FLAG_FINAL_PUT	10	/* set if final put has happened on key */

#define KEY_FLAG_USER_ALIVE	10	/* set if final put has not happened on key yet */



	/* the key type and key description string

	 * - the desc is used to match a key against search criteria

security/keys/gc.c

+2 −2
Original line number Diff line number Diff line
@@ -218,8 +218,8 @@ static void key_garbage_collector(struct work_struct *work) 
		key = rb_entry(cursor, struct key, serial_node);

		cursor = rb_next(cursor);



		if (test_bit(KEY_FLAG_FINAL_PUT, &key->flags)) {

			smp_mb(); /* Clobber key->user after FINAL_PUT seen. */

		if (!test_bit_acquire(KEY_FLAG_USER_ALIVE, &key->flags)) {

			/* Clobber key->user after final put seen. */

			goto found_unreferenced_key;

		}

security/keys/key.c

+3 −2
Original line number Diff line number Diff line
@@ -298,6 +298,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, 
	key->restrict_link = restrict_link;

	key->last_used_at = ktime_get_real_seconds();



	key->flags |= 1 << KEY_FLAG_USER_ALIVE;

	if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))

		key->flags |= 1 << KEY_FLAG_IN_QUOTA;

	if (flags & KEY_ALLOC_BUILT_IN)
@@ -658,8 +659,8 @@ void key_put(struct key *key) 
				key->user->qnbytes -= key->quotalen;

				spin_unlock_irqrestore(&key->user->lock, flags);

			}

			smp_mb(); /* key->user before FINAL_PUT set. */

			set_bit(KEY_FLAG_FINAL_PUT, &key->flags);

			/* Mark key as safe for GC after key->user done. */

			clear_bit_unlock(KEY_FLAG_USER_ALIVE, &key->flags);

			schedule_work(&key_gc_work);

		}

	}