change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/block/keyslot-manager.c
..
..
@@ -350,25 +350,16 @@
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 	return true;
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 }
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-/**
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- * blk_ksm_evict_key() - Evict a key from the lower layer device.
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- * @ksm: The keyslot manager to evict from
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- * @key: The key to evict
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- *
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- * Find the keyslot that the specified key was programmed into, and evict that
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- * slot from the lower layer device. The slot must not be in use by any
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- * in-flight IO when this function is called.
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- *
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- * Context: Process context. Takes and releases ksm->lock.
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- * Return: 0 on success or if there's no keyslot with the specified key, -EBUSY
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- *	   if the keyslot is still in use, or another -errno value on other
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- *	   error.
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+/*
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+ * This is an internal function that evicts a key from an inline encryption
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+ * device that can be either a real device or the blk-crypto-fallback "device".
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+ * It is used only by blk_crypto_evict_key(); see that function for details.
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  */
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 int blk_ksm_evict_key(struct blk_keyslot_manager *ksm,
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 		      const struct blk_crypto_key *key)
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 {
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 	struct blk_ksm_keyslot *slot;
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-	int err = 0;
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+	int err;
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 	if (blk_ksm_is_passthrough(ksm)) {
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 		if (ksm->ksm_ll_ops.keyslot_evict) {
..
..
@@ -382,22 +373,30 @@
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 	blk_ksm_hw_enter(ksm);
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 	slot = blk_ksm_find_keyslot(ksm, key);
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-	if (!slot)
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-		goto out_unlock;
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+	if (!slot) {
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+		/*
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+		 * Not an error, since a key not in use by I/O is not guaranteed
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+		 * to be in a keyslot.  There can be more keys than keyslots.
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+		 */
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+		err = 0;
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+		goto out;
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+	}
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 	if (WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)) {
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+		/* BUG: key is still in use by I/O */
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 		err = -EBUSY;
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-		goto out_unlock;
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+		goto out_remove;
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 	}
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 	err = ksm->ksm_ll_ops.keyslot_evict(ksm, key,
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 					    blk_ksm_get_slot_idx(slot));
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-	if (err)
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-		goto out_unlock;
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-
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+out_remove:
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+	/*
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+	 * Callers free the key even on error, so unlink the key from the hash
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+	 * table and clear slot->key even on error.
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+	 */
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 	hlist_del(&slot->hash_node);
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 	slot->key = NULL;
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-	err = 0;
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-out_unlock:
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+out:
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 	blk_ksm_hw_exit(ksm);
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 	return err;
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 }