linux-toradex.git/block/blk-mq-sysfs.c, branch v5.0-rc6

blk-mq: export hctx->type in debugfs instead of sysfs

2018-12-17T12:44:45+00:00

Now we only export hctx->type via sysfs, and there isn't such info
in hctx entry under debugfs. We often use debugfs only to diagnose
queue mapping issue, so add the support in debugfs.

Queue mapping becomes a bit more complicated after multiple queue
mapping is supported, we may write blktest to verify if queue mapping
is valid based on blk-mq-debugfs.

Given not necessary to export hctx->type twice, so remove the export
from sysfs.

Cc: Jeff Moyer 
Cc: Mike Snitzer 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: move queues types to the block layer

2018-12-04T18:38:17+00:00

Having another indirect all in the fast path doesn't really help
in our post-spectre world.  Also having too many queue type is just
going to create confusion, so I'd rather manage them centrally.

Note that the queue type naming and ordering changes a bit - the
first index now is the default queue for everything not explicitly
marked, the optional ones are read and poll queues.

Reviewed-by: Sagi Grimberg 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

blk-mq: not embed .mq_kobj and ctx->kobj into queue instance

2018-11-21T12:57:56+00:00

Even though .mq_kobj, ctx->kobj and q->kobj share same lifetime
from block layer's view, actually they don't because userspace may
grab one kobject anytime via sysfs.

This patch fixes the issue by the following approach:

1) introduce 'struct blk_mq_ctxs' for holding .mq_kobj and managing
all ctxs

2) free all allocated ctxs and the 'blk_mq_ctxs' instance in release
handler of .mq_kobj

3) grab one ref of .mq_kobj before initializing each ctx->kobj, so that
.mq_kobj is always released after all ctxs are freed.

This patch fixes kernel panic issue during booting when DEBUG_KOBJECT_RELEASE
is enabled.

Reported-by: Guenter Roeck 
Cc: "jianchao.wang" 
Tested-by: Guenter Roeck 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: remove a few unused exports

2018-11-15T19:13:25+00:00

Reviewed-by: Hannes Reinecke 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

blk-mq: add 'type' attribute to the sysfs hctx directory

2018-11-07T20:44:59+00:00

It can be useful for a user to verify what type a given hardware
queue is, expose this information in sysfs.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Bart Van Assche 
Reviewed-by: Keith Busch 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Jens Axboe

block drivers/block: Use octal not symbolic permissions

2018-05-24T19:38:59+00:00

Convert the S_ symbolic permissions to their octal equivalents as
using octal and not symbolic permissions is preferred by many as more
readable.

see: https://lkml.org/lkml/2016/8/2/1945

Done with automated conversion via:
$ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace 

Miscellanea:

o Wrapped modified multi-line calls to a single line where appropriate
o Realign modified multi-line calls to open parenthesis

Signed-off-by: Joe Perches 
Signed-off-by: Jens Axboe

block: properly protect the 'queue' kobj in blk_unregister_queue

2018-01-15T15:41:38+00:00

The original commit e9a823fb34a8b (block: fix warning when I/O elevator
is changed as request_queue is being removed) is pretty conflated.
"conflated" because the resource being protected by q->sysfs_lock isn't
the queue_flags (it is the 'queue' kobj).

q->sysfs_lock serializes __elevator_change() (via elv_iosched_store)
from racing with blk_unregister_queue():
1) By holding q->sysfs_lock first, __elevator_change() can complete
before a racing blk_unregister_queue().
2) Conversely, __elevator_change() is testing for QUEUE_FLAG_REGISTERED
in case elv_iosched_store() loses the race with blk_unregister_queue(),
it needs a way to know the 'queue' kobj isn't there.

Expand the scope of blk_unregister_queue()'s q->sysfs_lock use so it is
held until after the 'queue' kobj is removed.

To do so blk_mq_unregister_dev() must not also take q->sysfs_lock.  So
rename __blk_mq_unregister_dev() to blk_mq_unregister_dev().

Also, blk_unregister_queue() should use q->queue_lock to protect against
any concurrent writes to q->queue_flags -- even though chances are the
queue is being cleaned up so no concurrent writes are likely.

Fixes: e9a823fb34a8b ("block: fix warning when I/O elevator is changed as request_queue is being removed")
Signed-off-by: Mike Snitzer 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-mq: untangle debugfs and sysfs

2017-05-04T14:24:13+00:00

Originally, I tied debugfs registration/unregistration together with
sysfs. There's no reason to do this, and it's getting in the way of
letting schedulers define their own debugfs attributes. Instead, tie the
debugfs registration to the lifetime of the structures themselves.

The saner lifetimes mean we can also get rid of the extra mq directory
and move everything one level up. I.e., nvme0n1/mq/hctx0/tags is now
just nvme0n1/hctx0/tags.

Signed-off-by: Omar Sandoval 
Signed-off-by: Jens Axboe

blk-mq: move debugfs declarations to a separate header file

2017-05-04T14:23:44+00:00

Preparation for adding more declarations.

Signed-off-by: Omar Sandoval 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Jens Axboe

blk-mq: Only unregister hctxs for which registration succeeded

2017-04-26T21:09:04+00:00

Hctx unregistration involves calling kobject_del(). kobject_del()
must not be called if kobject_add() has not been called. Hence in
the error path only unregister hctxs for which registration succeeded.

Signed-off-by: Bart Van Assche 
Cc: Omar Sandoval 
Cc: Hannes Reinecke 
Signed-off-by: Jens Axboe