ide-atapi: accomodate transfer length calculation for ide-cd

... by factoring it out of ide_cd_do_request() into a helper, as suggested by
Bart.

There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
[bart: BLK_DEV_IDECD needs to select IDE_ATAPI now]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/Kconfig

@@ -137,6 +137,7 @@ config BLK_DEV_DELKIN
 
 config BLK_DEV_IDECD
 	tristate "Include IDE/ATAPI CDROM support"
+	select IDE_ATAPI
 	---help---
 	  If you have a CD-ROM drive using the ATAPI protocol, say Y. ATAPI is
 	  a newer protocol used by IDE CD-ROM and TAPE drives, similar to the

drivers/ide/ide-atapi.c

@@ -252,6 +252,18 @@ int ide_scsi_expiry(ide_drive_t *drive)
 }
 EXPORT_SYMBOL_GPL(ide_scsi_expiry);
 
+int ide_cd_get_xferlen(struct request *rq)
+{
+	if (blk_fs_request(rq))
+		return 32768;
+	else if (blk_sense_request(rq) || blk_pc_request(rq) ||
+			 rq->cmd_type == REQ_TYPE_ATA_PC)
+		return rq->data_len;
+	else
+		return 0;
+}
+EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
+
 /*
  * This is the usual interrupt handler which will be called during a packet
  * command.  We will transfer some of the data (as requested by the drive)
@@ -551,7 +563,7 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, unsigned int timeout,
 	struct ide_atapi_pc *pc = drive->pc;
 	ide_hwif_t *hwif = drive->hwif;
 	u32 tf_flags;
-	u16 bcount = 0;
+	u16 bcount;
 	u8 scsi = !!(drive->dev_flags & IDE_DFLAG_SCSI);
 
 	/* We haven't transferred any data yet */
@@ -560,6 +572,7 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, unsigned int timeout,
 
 	if (dev_is_idecd(drive)) {
 		tf_flags = IDE_TFLAG_OUT_NSECT | IDE_TFLAG_OUT_LBAL;
+		bcount = ide_cd_get_xferlen(hwif->hwgroup->rq);
 	} else if (scsi) {
 		tf_flags = 0;
 		bcount = min(pc->req_xfer, 63 * 1024);

drivers/ide/ide-cd.c

@@ -1214,8 +1214,9 @@ static ide_startstop_t ide_cd_do_request(ide_drive_t *drive, struct request *rq,
 		      __func__, rq->cmd[0], rq->cmd_type,
 		      (unsigned long long)block);
 
+	xferlen = ide_cd_get_xferlen(rq);
+
 	if (blk_fs_request(rq)) {
-		xferlen = 32768;
 		fn = cdrom_start_rw_cont;
 
 		if (cdrom_start_rw(drive, rq) == ide_stopped)
@@ -1225,7 +1226,6 @@ static ide_startstop_t ide_cd_do_request(ide_drive_t *drive, struct request *rq,
 			return ide_stopped;
 	} else if (blk_sense_request(rq) || blk_pc_request(rq) ||
 		   rq->cmd_type == REQ_TYPE_ATA_PC) {
-		xferlen = rq->data_len;
 		fn = cdrom_do_newpc_cont;
 
 		if (!rq->timeout)

include/linux/ide.h

@@ -1254,6 +1254,8 @@ static inline unsigned long ide_scsi_get_timeout(struct ide_atapi_pc *pc)
 
 int ide_scsi_expiry(ide_drive_t *);
 
+int ide_cd_get_xferlen(struct request *);
+
 ide_startstop_t ide_issue_pc(ide_drive_t *, unsigned int, ide_expiry_t *);
 
 ide_startstop_t do_rw_taskfile(ide_drive_t *, ide_task_t *);