mmc: block: Move boot partition locking into a driver op

This moves the boot partition lock command (issued from sysfs)
into a custom block layer request, just like the ioctl()s,
getting rid of yet another instance of mmc_get_card().

Since we now have two operations issuing special DRV_OP's, we
rename the result variable ->drv_op_result.

Tested by locking the boot partition from userspace:
> cd /sys/devices/platform/soc/80114000.sdi4_per2/mmc_host/mmc3/
     mmc3:0001/block/mmcblk3/mmcblk3boot0
> echo 1 > ro_lock_until_next_power_on
[  178.645324] mmcblk3boot1: Locking boot partition ro until next power on
[  178.652221] mmcblk3boot0: Locking boot partition ro until next power on

Also tested this with a huge dd job in the background: it
is now possible to lock the boot partitions on the card even
under heavy I/O.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/block.c

@@ -190,6 +190,8 @@ static ssize_t power_ro_lock_store(struct device *dev,
 	int ret;
 	struct mmc_blk_data *md, *part_md;
 	struct mmc_card *card;
+	struct mmc_queue *mq;
+	struct request *req;
 	unsigned long set;
 
 	if (kstrtoul(buf, 0, &set))
@@ -199,20 +201,14 @@ static ssize_t power_ro_lock_store(struct device *dev,
 		return count;
 
 	md = mmc_blk_get(dev_to_disk(dev));
+	mq = &md->queue;
 	card = md->queue.card;
 
-	mmc_get_card(card);
-
-	ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_WP,
-				card->ext_csd.boot_ro_lock |
-				EXT_CSD_BOOT_WP_B_PWR_WP_EN,
-				card->ext_csd.part_time);
-	if (ret)
-		pr_err("%s: Locking boot partition ro until next power on failed: %d\n", md->disk->disk_name, ret);
-	else
-		card->ext_csd.boot_ro_lock |= EXT_CSD_BOOT_WP_B_PWR_WP_EN;
-
-	mmc_put_card(card);
+	/* Dispatch locking to the block layer */
+	req = blk_get_request(mq->queue, REQ_OP_DRV_OUT, __GFP_RECLAIM);
+	req_to_mmc_queue_req(req)->drv_op = MMC_DRV_OP_BOOT_WP;
+	blk_execute_rq(mq->queue, NULL, req, 0);
+	ret = req_to_mmc_queue_req(req)->drv_op_result;
 
 	if (!ret) {
 		pr_info("%s: Locking boot partition ro until next power on\n",
@@ -606,7 +602,7 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
 	req_to_mmc_queue_req(req)->idata = idatas;
 	req_to_mmc_queue_req(req)->ioc_count = 1;
 	blk_execute_rq(mq->queue, NULL, req, 0);
-	ioc_err = req_to_mmc_queue_req(req)->ioc_result;
+	ioc_err = req_to_mmc_queue_req(req)->drv_op_result;
 	err = mmc_blk_ioctl_copy_to_user(ic_ptr, idata);
 	blk_put_request(req);
 
@@ -682,7 +678,7 @@ static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev,
 	req_to_mmc_queue_req(req)->idata = idata;
 	req_to_mmc_queue_req(req)->ioc_count = num_of_cmds;
 	blk_execute_rq(mq->queue, NULL, req, 0);
-	ioc_err = req_to_mmc_queue_req(req)->ioc_result;
+	ioc_err = req_to_mmc_queue_req(req)->drv_op_result;
 
 	/* copy to user if data and response */
 	for (i = 0; i < num_of_cmds && !err; i++)
@@ -1195,7 +1191,7 @@ static void mmc_blk_issue_drv_op(struct mmc_queue *mq, struct request *req)
 	struct mmc_queue_req *mq_rq;
 	struct mmc_card *card = mq->card;
 	struct mmc_blk_data *md = mq->blkdata;
-	int ioc_err;
+	int ret;
 	int i;
 
 	mq_rq = req_to_mmc_queue_req(req);
@@ -1203,23 +1199,34 @@ static void mmc_blk_issue_drv_op(struct mmc_queue *mq, struct request *req)
 	switch (mq_rq->drv_op) {
 	case MMC_DRV_OP_IOCTL:
 		for (i = 0; i < mq_rq->ioc_count; i++) {
-			ioc_err =
-				__mmc_blk_ioctl_cmd(card, md, mq_rq->idata[i]);
-			if (ioc_err)
+			ret = __mmc_blk_ioctl_cmd(card, md, mq_rq->idata[i]);
+			if (ret)
 				break;
 		}
-		mq_rq->ioc_result = ioc_err;
-
 		/* Always switch back to main area after RPMB access */
 		if (md->area_type & MMC_BLK_DATA_AREA_RPMB)
 			mmc_blk_part_switch(card, dev_get_drvdata(&card->dev));
-
-		blk_end_request_all(req, ioc_err);
+		break;
+	case MMC_DRV_OP_BOOT_WP:
+		ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_WP,
+				 card->ext_csd.boot_ro_lock |
+				 EXT_CSD_BOOT_WP_B_PWR_WP_EN,
+				 card->ext_csd.part_time);
+		if (ret)
+			pr_err("%s: Locking boot partition ro until next power on failed: %d\n",
+			       md->disk->disk_name, ret);
+		else
+			card->ext_csd.boot_ro_lock |=
+				EXT_CSD_BOOT_WP_B_PWR_WP_EN;
 		break;
 	default:
-		/* Unknown operation */
+		pr_err("%s: unknown driver specific operation\n",
+		       md->disk->disk_name);
+		ret = -EINVAL;
 		break;
 	}
+	mq_rq->drv_op_result = ret;
+	blk_end_request_all(req, ret);
 }
 
 static void mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)

drivers/mmc/core/queue.h

@@ -35,9 +35,11 @@ struct mmc_blk_request {
 /**
  * enum mmc_drv_op - enumerates the operations in the mmc_queue_req
  * @MMC_DRV_OP_IOCTL: ioctl operation
+ * @MMC_DRV_OP_BOOT_WP: write protect boot partitions
  */
 enum mmc_drv_op {
 	MMC_DRV_OP_IOCTL,
+	MMC_DRV_OP_BOOT_WP,
 };
 
 struct mmc_queue_req {
@@ -48,7 +50,7 @@ struct mmc_queue_req {
 	unsigned int		bounce_sg_len;
 	struct mmc_async_req	areq;
 	enum mmc_drv_op		drv_op;
-	int			ioc_result;
+	int			drv_op_result;
 	struct mmc_blk_ioc_data	**idata;
 	unsigned int		ioc_count;
 };