mmc: block: remove the check of packed for packed request routine

packed should always exist without calling its cleanup function
explicitly. Moreover, we have use it when preparing packed list.
So I don't believe we should ever fall into this check again when
doing mmc_blk_packed_hdr_wrq_prep or mmc_blk_end_packed_req,etc.
And the code of mmc_blk_end_packed_req is trying to use packed before
checking it which makes it quite weird. This patch is trying to
remove these two checks and move it to the mmc_blk_prep_packed_list.
If we find packed is null, then we should never use MMC_BLK_PACKED_CMD.
By doing this, we could fall back to non-packed request if finding null
packed, though it's impossible theoretically.

After removing these two BUG_ONs, we also remove all other similar
checks within the routine of mmc_blk_issue_rw_rq which checks the
error handling of packed request.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/card/block.c

@@ -142,8 +142,6 @@ static inline void mmc_blk_clear_packed(struct mmc_queue_req *mqrq)
 {
 	struct mmc_packed *packed = mqrq->packed;
 
-	BUG_ON(!packed);
-
 	mqrq->cmd_type = MMC_PACKED_NONE;
 	packed->nr_entries = MMC_PACKED_NR_ZERO;
 	packed->idx_failure = MMC_PACKED_NR_IDX;
@@ -1443,8 +1441,6 @@ static int mmc_blk_packed_err_check(struct mmc_card *card,
 	int err, check, status;
 	u8 *ext_csd;
 
-	BUG_ON(!packed);
-
 	packed->retries--;
 	check = mmc_blk_err_check(card, areq);
 	err = get_card_status(card, &status, 0);
@@ -1673,6 +1669,18 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
 	u8 max_packed_rw = 0;
 	u8 reqs = 0;
 
+	/*
+	 * We don't need to check packed for any further
+	 * operation of packed stuff as we set MMC_PACKED_NONE
+	 * and return zero for reqs if geting null packed. Also
+	 * we clean the flag of MMC_BLK_PACKED_CMD to avoid doing
+	 * it again when removing blk req.
+	 */
+	if (!mqrq->packed) {
+		md->flags &= (~MMC_BLK_PACKED_CMD);
+		goto no_packed;
+	}
+
 	if (!(md->flags & MMC_BLK_PACKED_CMD))
 		goto no_packed;
 
@@ -1782,8 +1790,6 @@ static void mmc_blk_packed_hdr_wrq_prep(struct mmc_queue_req *mqrq,
 	u8 hdr_blocks;
 	u8 i = 1;
 
-	BUG_ON(!packed);
-
 	mqrq->cmd_type = MMC_PACKED_WRITE;
 	packed->blocks = 0;
 	packed->idx_failure = MMC_PACKED_NR_IDX;
@@ -1887,8 +1893,6 @@ static int mmc_blk_end_packed_req(struct mmc_queue_req *mq_rq)
 	int idx = packed->idx_failure, i = 0;
 	int ret = 0;
 
-	BUG_ON(!packed);
-
 	while (!list_empty(&packed->list)) {
 		prq = list_entry_rq(packed->list.next);
 		if (idx == i) {
@@ -1917,8 +1921,6 @@ static void mmc_blk_abort_packed_req(struct mmc_queue_req *mq_rq)
 	struct request *prq;
 	struct mmc_packed *packed = mq_rq->packed;
 
-	BUG_ON(!packed);
-
 	while (!list_empty(&packed->list)) {
 		prq = list_entry_rq(packed->list.next);
 		list_del_init(&prq->queuelist);
@@ -1935,8 +1937,6 @@ static void mmc_blk_revert_packed_req(struct mmc_queue *mq,
 	struct request_queue *q = mq->queue;
 	struct mmc_packed *packed = mq_rq->packed;
 
-	BUG_ON(!packed);
-
 	while (!list_empty(&packed->list)) {
 		prq = list_entry_rq(packed->list.prev);
 		if (prq->queuelist.prev != &packed->list) {