-/*
- * Try to satisfy some of the current read request from our cached data.
- * Returns nonzero if the request has been completed, zero otherwise.
- */
-static int cdrom_read_from_buffer (ide_drive_t *drive)
-{
- struct cdrom_info *info = drive->driver_data;
- struct request *rq = HWGROUP(drive)->rq;
- unsigned short sectors_per_frame;
-
- sectors_per_frame = queue_hardsect_size(drive->queue) >> SECTOR_BITS;
-
- /* Can't do anything if there's no buffer. */
- if (info->buffer == NULL) return 0;
-
- /* Loop while this request needs data and the next block is present
- in our cache. */
- while (rq->nr_sectors > 0 &&
- rq->sector >= info->sector_buffered &&
- rq->sector < info->sector_buffered + info->nsectors_buffered) {
- if (rq->current_nr_sectors == 0)
- cdrom_end_request(drive, 1);
-
- memcpy (rq->buffer,
- info->buffer +
- (rq->sector - info->sector_buffered) * SECTOR_SIZE,
- SECTOR_SIZE);
- rq->buffer += SECTOR_SIZE;
- --rq->current_nr_sectors;
- --rq->nr_sectors;
- ++rq->sector;
- }
-
- /* If we've satisfied the current request,
- terminate it successfully. */
- if (rq->nr_sectors == 0) {
- cdrom_end_request(drive, 1);
- return -1;
- }
-
- /* Move on to the next buffer if needed. */
- if (rq->current_nr_sectors == 0)
- cdrom_end_request(drive, 1);
-
- /* If this condition does not hold, then the kluge i use to
- represent the number of sectors to skip at the start of a transfer
- will fail. I think that this will never happen, but let's be
- paranoid and check. */
- if (rq->current_nr_sectors < bio_cur_sectors(rq->bio) &&
- (rq->sector & (sectors_per_frame - 1))) {
- printk(KERN_ERR "%s: cdrom_read_from_buffer: buffer botch (%ld)\n",
- drive->name, (long)rq->sector);
- cdrom_end_request(drive, 0);
- return -1;
- }
-
- return 0;
-}
-