linux-toradex.git/block, branch v2.6.28-rc6

block: hold extra reference to bio in blk_rq_map_user_iov()

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

If the size passed in is OK but we end up mapping too many segments,
we call the unmap path directly like from IO completion. But from IO
completion we have an extra reference to the bio, so this error case
goes OOPS when it attempts to free and already free bio.

Fix it by getting an extra reference to the bio before calling the
unmap failure case.

Reported-by: Petr Vandrovec 

Signed-off-by: Jens Axboe

block: fix boot failure with CONFIG_DEBUG_BLOCK_EXT_DEVT=y and nash

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

We run into system boot failure with kernel 2.6.28-rc. We found it on a
couple of machines, including T61 notebook, nehalem machine, and another
HPC NX6325 notebook.  All the machines use FedoraCore 8 or FedoraCore 9.
With kernel prior to 2.6.28-rc, system boot doesn't fail.

I debug it and locate the root cause. Pls. see
http://bugzilla.kernel.org/show_bug.cgi?id=11899
https://bugzilla.redhat.com/show_bug.cgi?id=471517

As a matter of fact, there are 2 bugs.

1)root=/dev/sda1, system boot randomly fails. Mostly, boot for 5 times
and fails once. nash has a bug. Some of its functions misuse return
value 0.  Sometimes, 0 means timeout and no uevent available. Sometimes,
0 means nash gets an uevent, but the uevent isn't block-related (for
exmaple, usb). If by coincidence, kernel tells nash that uevents are
available, but kernel also set timeout, nash might stops collecting
other uevents in queue if current uevent isn't block-related.  I work
out a patch for nash to fix it.
http://bugzilla.kernel.org/attachment.cgi?id=18858

2) root=LABEL=/, system always can't boot. initrd init reports
switchroot fails. Here is an executation branch of nash when booting:
    (1) nash read /sys/block/sda/dev; Assume major is 8 (on my desktop)
    (2) nash query /proc/devices with the major number; It found line
	"8 sd";
    (3) nash use 'sd' to search its own probe table to find device (DISK)
	type for the device and add it to its own list;
    (4) Later on, it probes all devices in its list to get filesystem
	labels; scsi register "8 sd" always.

When major is 259, nash fails to find the device(DISK) type. I enables
CONFIG_DEBUG_BLOCK_EXT_DEVT=y when compiling kernel, so 259 is picked up
for device /dev/sda1, which causes nash to fail to find device (DISK)
type.

To fixing issue 2), I create a patch for nash and another patch for
kernel.

http://bugzilla.kernel.org/attachment.cgi?id=18859
http://bugzilla.kernel.org/attachment.cgi?id=18837

Below is the patch for kernel 2.6.28-rc4. It registers blkext, a new
block device in proc/devices.

With 2 patches on nash and 1 patch on kernel, I boot my machines for
dozens of times without failure.

Signed-off-by Zhang Yanmin 
Acked-by: Tejun Heo 
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

Block: use round_jiffies_up()

2008-11-06T07:42:49+00:00

This patch (as1159b) changes the timeout routines in the block core to
use round_jiffies_up().  There's no point in rounding the timer
deadline down, since if it expires too early we will have to restart
it.

The patch also removes some unnecessary tests when a request is
removed from the queue's timer list.

Signed-off-by: Alan Stern 
Signed-off-by: Jens Axboe

blk: move blk_delete_timer call in end_that_request_last

2008-11-06T07:41:56+00:00

Move the calling  blk_delete_timer to later in end_that_request_last to
address an issue where blkdev_dequeue_request may have add a timer for the
request.

Signed-off-by: Mike Anderson 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: add timer on blkdev_dequeue_request() not elv_next_request()

2008-11-06T07:41:55+00:00

Block queue supports two usage models - one where block driver peeks
at the front of queue using elv_next_request(), processes it and
finishes it and the other where block driver peeks at the front of
queue, dequeue the request using blkdev_dequeue_request() and finishes
it.  The latter is more flexible as it allows the driver to process
multiple commands concurrently.

These two inconsistent usage models affect the block layer
implementation confusing.  For some, elv_next_request() is considered
the issue point while others consider blkdev_dequeue_request() the
issue point.

Till now the inconsistency mostly affect only accounting, so it didn't
really break anything seriously; however, with block layer timeout,
this inconsistency hits hard.  Block layer considers
elv_next_request() the issue point and adds timer but SCSI layer
thinks it was just peeking and when the request can't process the
command right away, it's just left there without further processing.
This makes the request dangling on the timer list and, when the timer
goes off, the request which the SCSI layer and below think is still on
the block queue ends up in the EH queue, causing various problems - EH
hang (failed count goes over busy count and EH never wakes up),
WARN_ON() and oopses as low level driver trying to handle the unknown
command, etc. depending on the timing.

As SCSI midlayer is the only user of block layer timer at the moment,
moving blk_add_timer() to elv_dequeue_request() fixes the problem;
however, this two usage models definitely need to be cleaned up in the
future.

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

block: remove unused ll_new_mergeable()

2008-11-06T07:41:55+00:00

Signed-off-by: FUJITA Tomonori 
Signed-off-by: Jens Axboe

Merge branch 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc

2008-10-23T19:04:37+00:00

* 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc: (35 commits)
  proc: remove fs/proc/proc_misc.c
  proc: move /proc/vmcore creation to fs/proc/vmcore.c
  proc: move pagecount stuff to fs/proc/page.c
  proc: move all /proc/kcore stuff to fs/proc/kcore.c
  proc: move /proc/schedstat boilerplate to kernel/sched_stats.h
  proc: move /proc/modules boilerplate to kernel/module.c
  proc: move /proc/diskstats boilerplate to block/genhd.c
  proc: move /proc/zoneinfo boilerplate to mm/vmstat.c
  proc: move /proc/vmstat boilerplate to mm/vmstat.c
  proc: move /proc/pagetypeinfo boilerplate to mm/vmstat.c
  proc: move /proc/buddyinfo boilerplate to mm/vmstat.c
  proc: move /proc/vmallocinfo to mm/vmalloc.c
  proc: move /proc/slabinfo boilerplate to mm/slub.c, mm/slab.c
  proc: move /proc/slab_allocators boilerplate to mm/slab.c
  proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c
  proc: move /proc/stat to fs/proc/stat.c
  proc: move rest of /proc/partitions code to block/genhd.c
  proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c
  proc: move /proc/devices code to fs/proc/devices.c
  proc: move rest of /proc/locks to fs/locks.c
  ...

compat_blkdev_driver_ioctl: Remove unused variable warning

2008-10-23T17:28:25+00:00

Variable 'ret' is no longer used. Don't declare it.

Signed-off-by: Linus Torvalds

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