blk-mq: move debugging information from sysfs to debugfs

From: Omar Sandoval <[email protected]>

Changes from v1:

- Make the sbitmap seq_file helpers take a (struct sbitmap *) instead of a (void *), since it's not possible to use them directly as the seq_file show helper, anyways
- Fix a crash when reading ctx_map because it was attempting to do exactly that ^

Cover letter from v1:

This series ends our abuse of sysfs and puts all of the debugging information in debugfs instead. This has a few benefits:

1. Removes the possibility of userspace being stupid and relying on something in sysfs that we only exposed for debugging.
2. Lifts the limitations of sysfs, including the one-value-per-file convention and maximum of one page of output.
3. Allows us to add more debugging information that we often want but don't have when debugging a live system.

Thanks!
Omar

Omar Sandoval (10):
blk-mq: create debugfs directory tree
blk-mq: add hctx->{state,flags} to debugfs
blk-mq: move hctx->dispatch and ctx->rq_list from sysfs to debugfs
blk-mq: add extra request information to debugfs
sbitmap: add helpers for dumping to a seq_file
blk-mq: export software queue pending map to debugfs
blk-mq: move tags and sched_tags info from sysfs to debugfs
blk-mq: add tags and sched_tags bitmaps to debugfs
blk-mq: move hctx io_poll, stats, and dispatched from sysfs to debugfs
blk-mq: move hctx and ctx counters from sysfs to debugfs

 block/Makefile          |   1 +
 block/blk-mq-debugfs.c  | 756 ++++++++++++++++++++++++++++++++++++++++++++++++
 block/blk-mq-sysfs.c    | 248 ++--------------
 block/blk-mq-tag.c      |  27 --
 block/blk-mq-tag.h      |   1 -
 block/blk-mq.c          |   2 +
 block/blk-mq.h          |  33 +++
 include/linux/blkdev.h  |   5 +
 include/linux/sbitmap.h |  28 ++
 lib/sbitmap.c           |  74 +++++
 10 files changed, 920 insertions(+), 255 deletions(-)
 create mode 100644 block/blk-mq-debugfs.c

2.11.0