linux-stable.git/include/linux/genhd.h, branch linux-2.6.30.y

block: include empty disks in /proc/diskstats

2009-04-22T06:35:10+00:00

/proc/diskstats used to show stats for all disks whether they're
zero-sized or not and their non-zero partitions.  Commit
074a7aca7afa6f230104e8e65eba3420263714a5 accidentally changed the
behavior such that it doesn't print out zero sized disks.  This patch
implements DISK_PITER_INCL_EMPTY_PART0 flag to partition iterator and
uses it in diskstats_show() such that empty part0 is shown in
/proc/diskstats.

Reported and bisectd by Dianel Collins.

Signed-off-by: Tejun Heo 
Reported-by: Daniel Collins 
Signed-off-by: Jens Axboe

block: genhd.h cleanup patch

2009-03-24T11:35:17+00:00

In include/linux/genhd.h: Line 335 has a comment that needs to be updated from: /* drivers/block/ll_rw_blk.c */ to /* block/blk-core.c */. Also as of kernel 2.6.16, the function definition for get_blkdev_list was removed from block/genhd.c but the function declaration is still present on line 339. This patch addresses both those fixes, by updating the comment and removing the declaration.

Signed-off-by: Petros Koutoupis 
Signed-off-by: Jens Axboe

block: genhd.h comment needs updating

2009-03-24T11:35:17+00:00

The include/linux/genhd.h file, on line 338-352 declares some function
prototypes in which the comment on line 338 states that the definition of
these prototypes are to be found at drivers/block/genhd.c. The problem is
that genhd.c has been relocated to block/genhd.c. See attached patch to
correct this minor cosmetic typo.

Signed-off-by: Petros Koutoupis 
Signed-off-by: Jens Axboe

block: add one-hit cache for disk partition lookup

2008-12-29T07:29:51+00:00

disk_map_sector_rcu() returns a partition from a sector offset,
which we use for IO statistics on a per-partition basis. The
lookup itself is an O(N) list lookup, where N is the number of
partitions. This actually hurts performance quite a bit, even
on the lower end partitions. On higher numbered partitions,
it can get pretty bad.

Solve this by adding a one-hit cache for partition lookup.
This makes the lookup O(1) for the case where we do most IO to
one partition. Even for mixed partition workloads, amortized cost
is pretty close to O(1) since the natural IO batching makes the
one-hit cache last for lots of IOs.

Signed-off-by: Jens Axboe

block: make add_partition() return pointer to hd_struct

2008-11-18T14:08:56+00:00

Make add_partition() return pointer to the new hd_struct on success
and ERR_PTR() value on failure.  This change will be used to fix md
autodetection bug.

Signed-off-by: Tejun Heo 
Cc: Neil Brown 
Signed-off-by: Jens Axboe

proc: move /proc/diskstats boilerplate to block/genhd.c

2008-10-23T13:57:37+00:00

Signed-off-by: Alexey Dobriyan 
Acked-by: Jens Axboe

proc: move rest of /proc/partitions code to block/genhd.c

2008-10-23T11:07:31+00:00

Signed-off-by: Alexey Dobriyan 
Acked-by: Jens Axboe

block: allow disk to have extended device number

2008-10-09T06:56:08+00:00

Now that disk and partition handlings are mostly unified, it's easy to
allow disk to have extended device number.  This patch makes
add_disk() use extended device number if disk->minors is zero.  Both
sd and ide-disk are updated to use this.

* sd_format_disk_name() is implemented which can generically determine
  the drive name.  This removes disk number restriction stemming from
  limited device names.

* If sd index goes over SD_MAX_DISKS (which can be increased now BTW),
  sd simply doesn't initialize minors letting block layer choose
  extended device number.

* If CONFIG_DEBUG_EXT_DEVT is set, both sd and ide-disk always set
  minors to 0 and use extended device numbers.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: replace @ext_minors with GENHD_FL_EXT_DEVT

2008-10-09T06:56:08+00:00

With previous changes, it's meaningless to limit the number of
partitions.  Replace @ext_minors with GENHD_FL_EXT_DEVT such that
setting the flag allows the disk to have maximum number of allowed
partitions (only limited by the number of entries in parsed_partitions
as determined by MAX_PART constant).

This kills not-too-pretty alloc_disk_ext[_node]() functions and makes
@minors parameter to alloc_disk[_node]() unnecessary.  The parameter
is left alone to avoid disturbing the users.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: make partition array dynamic

2008-10-09T06:56:08+00:00

disk->__part used to be statically allocated to the maximum possible
number of partitions.  This patch makes partition array allocation
dynamic.  The added overhead is minimal as only real change is one
memory dereference changed to RCU one.  This saves both a bit of
memory and cpu cycles iterating through unoccupied slots and makes
increasing partition limit easier.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe