linux-stable.git/include/linux/blk_types.h, branch v3.2.102

Defer processing of REQ_PREEMPT requests for blocked devices

2015-05-09T22:16:35+00:00

commit bba0bdd7ad4713d82338bcd9b72d57e9335a664b upstream.

SCSI transport drivers and SCSI LLDs block a SCSI device if the
transport layer is not operational. This means that in this state
no requests should be processed, even if the REQ_PREEMPT flag has
been set. This patch avoids that a rescan shortly after a cable
pull sporadically triggers the following kernel oops:

BUG: unable to handle kernel paging request at ffffc9001a6bc084
IP: [] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib]
Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100)
Call Trace:
 [] srp_post_send+0x65/0x70 [ib_srp]
 [] srp_queuecommand+0x1cf/0x3e0 [ib_srp]
 [] scsi_dispatch_cmd+0x101/0x280 [scsi_mod]
 [] scsi_request_fn+0x411/0x4d0 [scsi_mod]
 [] __blk_run_queue+0x27/0x30
 [] blk_execute_rq_nowait+0x82/0x110
 [] blk_execute_rq+0x62/0xf0
 [] scsi_execute+0xe8/0x190 [scsi_mod]
 [] scsi_execute_req+0xa3/0x130 [scsi_mod]
 [] scsi_probe_lun+0x17a/0x450 [scsi_mod]
 [] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod]
 [] __scsi_scan_target+0xdf/0x1f0 [scsi_mod]
 [] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod]
 [] scsi_scan+0xdb/0xe0 [scsi_mod]
 [] store_scan+0x13/0x20 [scsi_mod]
 [] sysfs_write_file+0xcb/0x160
 [] vfs_write+0xce/0x140
 [] sys_write+0x53/0xa0
 [] system_call_fastpath+0x16/0x1b
 [<00007f611c9d9300>] 0x7f611c9d92ff

Reported-by: Max Gurtuvoy 
Signed-off-by: Bart Van Assche 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley 
Signed-off-by: Ben Hutchings

block: Remove the control of complete cpu from bio.

2011-10-24T14:11:30+00:00

bio originally has the functionality to set the complete cpu, but
it is broken.

Chirstoph said that "This code is unused, and from the all the
discussions lately pretty obviously broken.  The only thing keeping
it serves is creating more confusion and possibly more bugs."

And Jens replied with "We can kill bio_set_completion_cpu(). I'm fine
with leaving cpu control to the request based drivers, they are the
only ones that can toggle the setting anyway".

So this patch tries to remove all the work of controling complete cpu
from a bio.

Cc: Shaohua Li 
Cc: Christoph Hellwig 
Signed-off-by: Tao Ma 
Signed-off-by: Jens Axboe

block: separate priority boosting from REQ_META

2011-08-23T12:50:29+00:00

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Namhyung Kim 
Signed-off-by: Jens Axboe

Move some REQ flags to the common bio/request area

2011-08-11T08:36:03+00:00

REQ_SECURE, REQ_FLUSH and REQ_FUA may all be set on a bio as well as
on a request, so relocate them to the shared part of the enum.

Signed-off-by: Matthew Wilcox 
Signed-off-by: Namhyung Kim 
Reviewed-by: Jeff Moyer 
Signed-off-by: Jens Axboe

block: add REQ_SECURE to REQ_COMMON_MASK

2011-06-20T11:23:14+00:00

Add REQ_SECURE flag to REQ_COMMON_MASK so that
init_request_from_bio() can pass it to @req->cmd_flags.

Signed-off-by: Namhyung Kim 
Acked-by: Adrian Hunter 
Cc: stable@kernel.org # 2.6.36 and newer
Signed-off-by: Jens Axboe

block: get rid of on-stack plugging debug checks

2011-05-20T18:52:16+00:00

We don't need them anymore, so kill:

- REQ_ON_PLUG checks in various places
- !rq_mergeable() check in plug merging

Signed-off-by: Jens Axboe

block: kill off REQ_UNPLUG

2011-03-10T07:52:27+00:00

With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.

Signed-off-by: Jens Axboe

block: initial patch for on-stack per-task plugging

2011-03-10T07:45:54+00:00

This patch adds support for creating a queuing context outside
of the queue itself. This enables us to batch up pieces of IO
before grabbing the block device queue lock and submitting them to
the IO scheduler.

The context is created on the stack of the process and assigned in
the task structure, so that we can auto-unplug it if we hit a schedule
event.

The current queue plugging happens implicitly if IO is submitted to
an empty device, yet callers have to remember to unplug that IO when
they are going to wait for it. This is an ugly API and has caused bugs
in the past. Additionally, it requires hacks in the vm (->sync_page()
callback) to handle that logic. By switching to an explicit plugging
scheme we make the API a lot nicer and can get rid of the ->sync_page()
hack in the vm.

Signed-off-by: Jens Axboe

block: add REQ_FLUSH_SEQ

2011-01-25T11:43:49+00:00

rq == &q->flush_rq was used to determine whether a rq is part of a
flush sequence, which worked because all requests in a flush sequence
were sequenced using the single dedicated request.  This is about to
change, so introduce REQ_FLUSH_SEQ flag to distinguish flush sequence
requests.

This patch doesn't cause any behavior change.

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

block: remove REQ_HARDBARRIER

2010-11-10T13:54:09+00:00

REQ_HARDBARRIER is dead now, so remove the leftovers.  What's left
at this point is:

 - various checks inside the block layer.
 - sanity checks in bio based drivers.
 - now unused bio_empty_barrier helper.
 - Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while,
   but Xen really needs to sort out it's barrier situaton.
 - setting of ordered tags in uas - dead code copied from old scsi
   drivers.
 - scsi different retry for barriers - it's dead and should have been
   removed when flushes were converted to FS requests.
 - blktrace handling of barriers - removed.  Someone who knows blktrace
   better should add support for REQ_FLUSH and REQ_FUA, though.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe