ide: add generic packet command representation ide_atapi_pc

This new struct unifies ide{-floppy,-tape,-scsi}'s view of a packet command. For now,
it represents the common denominator between the three drivers while adding driver-
specific members at the end of the struct which will be merged/simplified into the
generic ATAPI handling code in later steps, or removed completely.

Bart:
- move struct ide_atapi_pc outside of #ifdef/#endif CONFIG_IDE_PROC_FS
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

include/linux/ide.h

@@ -595,6 +595,53 @@ int set_io_32bit(ide_drive_t *, int);
 int set_pio_mode(ide_drive_t *, int);
 int set_using_dma(ide_drive_t *, int);
 
+struct ide_atapi_pc {
+	/* actual packet bytes */
+	u8 c[12];
+	/* incremented on each retry */
+	int retries;
+	int error;
+
+	/* bytes to transfer */
+	int req_xfer;
+	/* bytes actually transferred */
+	int xferred;
+
+	/* data buffer */
+	u8 *buf;
+	/* current buffer position */
+	u8 *cur_pos;
+	int buf_size;
+	/* missing/available data on the current buffer */
+	int b_count;
+
+	/* the corresponding request */
+	struct request *rq;
+
+	unsigned long flags;
+
+	/*
+	 * those are more or less driver-specific and some of them are subject
+	 * to change/removal later.
+	 */
+	u8 pc_buf[256];
+	void (*idefloppy_callback) (ide_drive_t *);
+	ide_startstop_t (*idetape_callback) (ide_drive_t *);
+
+	/* idetape only */
+	struct idetape_bh *bh;
+	char *b_data;
+
+	/* idescsi only for now */
+	struct scatterlist *sg;
+	unsigned int sg_cnt;
+
+	struct scsi_cmnd *scsi_cmd;
+	void (*done) (struct scsi_cmnd *);
+
+	unsigned long timeout;
+};
+
 #ifdef CONFIG_IDE_PROC_FS
 /*
  * configurable drive settings