The patch below cleans up some SCSI stuff.

The main purpose is to avoid trying to read the partition table
of a removable disk when the drive has told us that no media
are present. (Right now we try to read a 4K block and fail and
retry and fail, and give an I/O error on the first sector,
then try to read the second sector and fail and retry ...)

Unused fields  sector_bit_size  and  sector_bit_shift  in
struct scsi_disk were removed. The field  has_part_table
(that has nothing to do with partition tables) was
renamed to  has_been_registered . The field  ready  was
renamed to  media_present .
The overly long  sd_init_onedisk()  was split up.

When we notice that no media are present anymore, the
partitions are removed from /proc/partitions, but the
drive remains, with size 0.

A future patch will remove the field  capacity  - there are
all too many places where capacities are stored - but the
present patch is large enough already.

There is also a quite independent patch in scsi_error.c
(yesterday someone had an infinite loop retrying to read
bad media) - this patch honours the SCpnt->retries.
In case you applied this already, just ignore the scsi_error.c part.

Also some "Overrides for Emacs" were removed.