mg_disk: clean up request completion paths

mg_disk implements its own partial completion.  Convert to standard
block layer partial completion.

[ Impact: cleanup ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/block/mg_disk.c

@@ -503,95 +503,68 @@ static unsigned int mg_out(struct mg_host *host,
 
 static void mg_read(struct request *req)
 {
-	u32 remains, j;
+	u32 j;
 	struct mg_host *host = req->rq_disk->private_data;
 
-	remains = req->nr_sectors;
-
 	if (mg_out(host, req->sector, req->nr_sectors, MG_CMD_RD, NULL) !=
 			MG_ERR_NONE)
 		mg_bad_rw_intr(host);
 
 	MG_DBG("requested %d sects (from %ld), buffer=0x%p\n",
-			remains, req->sector, req->buffer);
+	       req->nr_sectors, req->sector, req->buffer);
+
+	do {
+		u16 *buff = (u16 *)req->buffer;
 
-	while (remains) {
 		if (mg_wait(host, MG_REG_STATUS_BIT_DATA_REQ,
 					MG_TMAX_WAIT_RD_DRQ) != MG_ERR_NONE) {
 			mg_bad_rw_intr(host);
 			return;
 		}
-		for (j = 0; j < MG_SECTOR_SIZE >> 1; j++) {
-			*(u16 *)req->buffer =
-				inw((unsigned long)host->dev_base +
+		for (j = 0; j < MG_SECTOR_SIZE >> 1; j++)
+			*buff++ = inw((unsigned long)host->dev_base +
 				      MG_BUFF_OFFSET + (j << 1));
-			req->buffer += 2;
-		}
-
-		req->sector++;
-		req->errors = 0;
-		remains = --req->nr_sectors;
-		--req->current_nr_sectors;
-
-		if (req->current_nr_sectors <= 0) {
-			MG_DBG("remain : %d sects\n", remains);
-			__blk_end_request_cur(req, 0);
-			if (remains > 0)
-				req = elv_next_request(host->breq);
-		}
 
 		outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base +
 				MG_REG_COMMAND);
-	}
+	} while (__blk_end_request(req, 0, MG_SECTOR_SIZE));
 }
 
 static void mg_write(struct request *req)
 {
-	u32 remains, j;
+	u32 j;
 	struct mg_host *host = req->rq_disk->private_data;
 
-	remains = req->nr_sectors;
-
 	if (mg_out(host, req->sector, req->nr_sectors, MG_CMD_WR, NULL) !=
 			MG_ERR_NONE) {
 		mg_bad_rw_intr(host);
 		return;
 	}
 
-
 	MG_DBG("requested %d sects (from %ld), buffer=0x%p\n",
-			remains, req->sector, req->buffer);
-	while (remains) {
+	       req->nr_sectors, req->sector, req->buffer);
+
+	do {
+		u16 *buff = (u16 *)req->buffer;
+
 		if (mg_wait(host, MG_REG_STATUS_BIT_DATA_REQ,
 					MG_TMAX_WAIT_WR_DRQ) != MG_ERR_NONE) {
 			mg_bad_rw_intr(host);
 			return;
 		}
-		for (j = 0; j < MG_SECTOR_SIZE >> 1; j++) {
-			outw(*(u16 *)req->buffer,
-					(unsigned long)host->dev_base +
+		for (j = 0; j < MG_SECTOR_SIZE >> 1; j++)
+			outw(*buff++, (unsigned long)host->dev_base +
 				      MG_BUFF_OFFSET + (j << 1));
-			req->buffer += 2;
-		}
-		req->sector++;
-		remains = --req->nr_sectors;
-		--req->current_nr_sectors;
-
-		if (req->current_nr_sectors <= 0) {
-			MG_DBG("remain : %d sects\n", remains);
-			__blk_end_request_cur(req, 0);
-			if (remains > 0)
-				req = elv_next_request(host->breq);
-		}
 
 		outb(MG_CMD_WR_CONF, (unsigned long)host->dev_base +
 				MG_REG_COMMAND);
-	}
+	} while (__blk_end_request(req, 0, MG_SECTOR_SIZE));
 }
 
 static void mg_read_intr(struct mg_host *host)
 {
 	u32 i;
+	u16 *buff;
 	struct request *req;
 
 	/* check status */
@@ -612,39 +585,24 @@ static void mg_read_intr(struct mg_host *host)
 ok_to_read:
 	/* get current segment of request */
 	req = elv_next_request(host->breq);
+	buff = (u16 *)req->buffer;
 
 	/* read 1 sector */
-	for (i = 0; i < MG_SECTOR_SIZE >> 1; i++) {
-		*(u16 *)req->buffer =
-			inw((unsigned long)host->dev_base + MG_BUFF_OFFSET +
+	for (i = 0; i < MG_SECTOR_SIZE >> 1; i++)
+		*buff++ = inw((unsigned long)host->dev_base + MG_BUFF_OFFSET +
 			      (i << 1));
-		req->buffer += 2;
-	}
 
-	/* manipulate request */
 	MG_DBG("sector %ld, remaining=%ld, buffer=0x%p\n",
 			req->sector, req->nr_sectors - 1, req->buffer);
 
-	req->sector++;
-	req->errors = 0;
-	i = --req->nr_sectors;
-	--req->current_nr_sectors;
-
-	/* let know if current segment done */
-	if (req->current_nr_sectors <= 0)
-		__blk_end_request_cur(req, 0);
+	/* send read confirm */
+	outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);
 
+	if (__blk_end_request(req, 0, MG_SECTOR_SIZE)) {
 		/* set handler if read remains */
-	if (i > 0) {
 		host->mg_do_intr = mg_read_intr;
 		mod_timer(&host->timer, jiffies + 3 * HZ);
-	}
-
-	/* send read confirm */
-	outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);
-
-	/* goto next request */
-	if (!i)
+	} else /* goto next request */
 		mg_request(host->breq);
 }
 
@@ -653,6 +611,7 @@ static void mg_write_intr(struct mg_host *host)
 	u32 i, j;
 	u16 *buff;
 	struct request *req;
+	bool rem;
 
 	/* get current segment of request */
 	req = elv_next_request(host->breq);
@@ -673,18 +632,8 @@ static void mg_write_intr(struct mg_host *host)
 	return;
 
 ok_to_write:
-	/* manipulate request */
-	req->sector++;
-	i = --req->nr_sectors;
-	--req->current_nr_sectors;
-	req->buffer += MG_SECTOR_SIZE;
-
-	/* let know if current segment or all done */
-	if (!i || (req->bio && req->current_nr_sectors <= 0))
-		__blk_end_request_cur(req, 0);
-
+	if ((rem = __blk_end_request(req, 0, MG_SECTOR_SIZE))) {
 		/* write 1 sector and set handler if remains */
-	if (i > 0) {
 		buff = (u16 *)req->buffer;
 		for (j = 0; j < MG_STORAGE_BUFFER_SIZE >> 1; j++) {
 			outw(*buff, (unsigned long)host->dev_base +
@@ -700,7 +649,7 @@ static void mg_write_intr(struct mg_host *host)
 	/* send write confirm */
 	outb(MG_CMD_WR_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);
 
-	if (!i)
+	if (!rem)
 		mg_request(host->breq);
 }