mmc: Flush block queue when removing card

After mmc_block's remove function has exited, we must not
touch the card structure in any way. This means we not only
must remove the gendisk, we must also flush out any
remaning requests already queued up.

We previously removed the disk, but didn't flush it,
causing oops:es when removing a card in the middle of a
transfer.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/mmc_block.c

@@ -83,7 +83,6 @@ static void mmc_blk_put(struct mmc_blk_data *md)
 	md->usage--;
 	if (md->usage == 0) {
 		put_disk(md->disk);
-		mmc_cleanup_queue(&md->queue);
 		kfree(md);
 	}
 	mutex_unlock(&open_lock);
@@ -553,12 +552,11 @@ static void mmc_blk_remove(struct mmc_card *card)
 	if (md) {
 		int devidx;
 
+		/* Stop new requests from getting into the queue */
 		del_gendisk(md->disk);
 
-		/*
-		 * I think this is needed.
-		 */
-		md->disk->queue = NULL;
+		/* Then flush out any already in there */
+		mmc_cleanup_queue(&md->queue);
 
 		devidx = md->disk->first_minor >> MMC_SHIFT;
 		__clear_bit(devidx, dev_use);

drivers/mmc/mmc_queue.c

@@ -103,6 +103,19 @@ static int mmc_queue_thread(void *d)
 static void mmc_request(request_queue_t *q)
 {
 	struct mmc_queue *mq = q->queuedata;
+	struct request *req;
+	int ret;
+
+	if (!mq) {
+		printk(KERN_ERR "MMC: killing requests for dead queue\n");
+		while ((req = elv_next_request(q)) != NULL) {
+			do {
+				ret = end_that_request_chunk(req, 0,
+					req->current_nr_sectors << 9);
+			} while (ret);
+		}
+		return;
+	}
 
 	if (!mq->req)
 		wake_up_process(mq->thread);
@@ -168,6 +181,15 @@ EXPORT_SYMBOL(mmc_init_queue);
 
 void mmc_cleanup_queue(struct mmc_queue *mq)
 {
+	request_queue_t *q = mq->queue;
+	unsigned long flags;
+
+	/* Mark that we should start throwing out stragglers */
+	spin_lock_irqsave(q->queue_lock, flags);
+	q->queuedata = NULL;
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	/* Then terminate our worker thread */
 	kthread_stop(mq->thread);
 
 	kfree(mq->sg);