Merge blk_mq_try_issue_directly and __blk_mq_try_issue_directly
into one interface to unify the interfaces to issue requests
directly. The merged interface takes over the requests totally,
it could insert, end or do nothing based on the return value of
.queue_rq and 'bypass' parameter. Then caller needn't any other
handling any more and then code could be cleaned up.

And also the commit c616cbee ( blk-mq: punt failed direct issue
to dispatch list ) always inserts requests to hctx dispatch list
whenever get a BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE, this is
overkill and will harm the merging. We just need to do that for
the requests that has been through .queue_rq. This patch also
could fix this.
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

free the controller discard_page correctly.

Fixes: cb5b7262 ("nvme: provide fallback for discard alloc failure")
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Pull NVMe updates from Christoph:

"Here is the second large chunk of nvme updates for 4.21:

 - host and target support for NVMe over TCP (Sagi Grimberg,
	Roy Shterman, Solganik Alexander)
 - error log page support in target (Chaitanya Kulkarni)

plus small fixes and improvements from Jens Axboe and Chengguang Xu."

* 'nvme-4.21' of git://git.infradead.org/nvme: (33 commits)
  nvme-rdma: support separate queue maps for read and write
  nvme-tcp: support separate queue maps for read and write
  nvme-fabrics: allow user to set nr_write_queues for separate queue maps
  nvme-fabrics: add missing nvmf_ctrl_options documentation
  blk-mq-rdma: pass in queue map to blk_mq_rdma_map_queues
  nvmet: update smart log with num err log entries
  nvmet: add error log page cmd handler
  nvmet: add error log support for file backend
  nvmet: add error log support for bdev backend
  nvmet: add error log support for admin-cmd
  nvmet: add error log support for rdma backend
  nvmet: add error log support for fabrics-cmd
  nvmet: add error log support in the core
  nvmet: add interface to update error-log page
  nvmet: add error-log definitions
  nvme: add error log page slot definition
  nvme: remove nvme_common command cdw10 array
  nvmet: remove unused variable
  nvme: provide fallback for discard alloc failure
  nvme: add __exit annotation
  ...

Sometimes flush journal may be very frequent, so it's useful to dump
number of keys every time write journal.
Signed-off-by: NGuoju Fang <fangguoju@gmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Because CUTOFF_WRITEBACK is defined as 40, so before the changes of
dynamic cutoff writeback values, writeback_percent is limited to [0,
CUTOFF_WRITEBACK]. Any value larger than CUTOFF_WRITEBACK will be fixed
up to 40.

Now cutof writeback limit is a dynamic value bch_cutoff_writeback, so
the range of writeback_percent can be a more flexible range as [0,
bch_cutoff_writeback]. The flexibility is, it can be expended to a
larger or smaller range than [0, 40], depends on how value
bch_cutoff_writeback is specified.

The default value is still strongly recommended to most of users for
most of workloads. But for people who want to do research on bcache
writeback perforamnce tuning, they may have chance to specify more
flexible writeback_percent in range [0, 70].
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently the cutoff writeback and cutoff writeback sync thresholds are
defined by CUTOFF_WRITEBACK (40) and CUTOFF_WRITEBACK_SYNC (70) as
static values. Most of time these they work fine, but when people want
to do research on bcache writeback mode performance tuning, there is no
chance to modify the soft and hard cutoff writeback values.

This patch introduces two module parameters bch_cutoff_writeback_sync
and bch_cutoff_writeback which permit people to tune the values when
loading bcache.ko. If they are not specified by module loading, current
values CUTOFF_WRITEBACK_SYNC and CUTOFF_WRITEBACK will be used as
default and nothing changes.

When people want to tune this two values,
- cutoff_writeback can be set in range [1, 70]
- cutoff_writeback_sync can be set in range [1, 90]
- cutoff_writeback always <= cutoff_writeback_sync

The default values are strongly recommended to most of users for most of
workloads. Anyway, if people wants to take their own risk to do research
on new writeback cutoff tuning for their own workload, now they can make
it.
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This patch moves MODULE_AUTHOR and MODULE_LICENSE to end of super.c, and
add MODULE_DESCRIPTION("Bcache: a Linux block layer cache").

This is preparation for adding module parameters.
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The option gc_after_writeback is disabled by default, because garbage
collection will discard SSD data which drops cached data.

Echo 1 into /sys/fs/bcache/<UUID>/internal/gc_after_writeback will
enable this option, which wakes up gc thread when writeback accomplished
and all cached data is clean.

This option is helpful for people who cares writing performance more. In
heavy writing workload, all cached data can be clean only happens when
writeback thread cleans all cached data in I/O idle time. In such
situation a following gc running may help to shrink bcache B+ tree and
discard more clean data, which may be helpful for future writing
requests.

If you are not sure whether this is helpful for your own workload,
please leave it as disabled by default.
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Garbage collection thread starts to work when c->sectors_to_gc is
negative value, otherwise nothing will happen even the gc thread is
woken up by wake_up_gc().

force_wake_up_gc() sets c->sectors_to_gc to -1 before calling
wake_up_gc(), then gc thread may have chance to run if no one else sets
c->sectors_to_gc to a positive value before gc_should_run().

This routine can be called where the gc thread is woken up and required
to run in force.
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

"echo 1 > writeback_running" marks writeback_running even if no
writeback kthread created as "d_strtoul(writeback_running)" will simply
set dc-> writeback_running without checking the existence of
dc->writeback_thread.

Add check for setting writeback_running via sysfs: if no writeback
kthread available, reject setting to 1.

v2 -> v3:
  * Make message on wrong assignment more clear.
  * Print name of bcache device instead of name of backing device.
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

A fresh backing device is not attached to any cache_set, and
has no writeback kthread created until first attached to some
cache_set.

But bch_cached_dev_writeback_init run
"
	dc->writeback_running		= true;
	WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING,
			&dc->disk.flags));
"
for any newly formatted backing devices.

For a fresh standalone backing device, we can get something like
following even if no writeback kthread created:
------------------------
/sys/block/bcache0/bcache# cat writeback_running
1
/sys/block/bcache0/bcache# cat writeback_rate_debug
rate:		512.0k/sec
dirty:		0.0k
target:		0.0k
proportional:	0.0k
integral:	0.0k
change:		0.0k/sec
next io:	-15427384ms

The none ZERO fields are misleading as no alive writeback kthread yet.

Set dc->writeback_running false as no writeback thread created in
bch_cached_dev_writeback_init().

We have writeback thread created and woken up in bch_cached_dev_writeback
_start(). Set dc->writeback_running true before bch_writeback_queue()
called, as a writeback thread will check if dc->writeback_running is true
before writing back dirty data, and hung if false detected.

After the change, we can get the following output for a fresh standalone
backing device:
-----------------------
/sys/block/bcache0/bcache$ cat writeback_running
0
/sys/block/bcache0/bcache# cat writeback_rate_debug
rate:		0.0k/sec
dirty:		0.0k
target:		0.0k
proportional:	0.0k
integral:	0.0k
change:		0.0k/sec
next io:	0ms

v1 -> v2:
  Set dc->writeback_running before bch_writeback_queue() called,
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We have struct cached_dev allocated by kzalloc in register_bcache(),
which initializes all the fields of cached_dev with 0s. And commit
ce4c3e19 ("bcache: Replace bch_read_string_list() by
__sysfs_match_string()") has remove the string "default".

Update the comment.
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

commit 220bb38c ("bcache: Break up struct search") introduced
changes to struct search and s->iop. bypass/bio are fields of struct
data_insert_op now. Update the comment.
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

debugfs_remove and debugfs_remove_recursive will check if the dentry
pointer is NULL or ERR, and will do nothing in that case.

Remove the check in cache_set_free and bch_debug_init.
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We have the following define for btree iterator:
	struct btree_iter {
		size_t size, used;
	#ifdef CONFIG_BCACHE_DEBUG
		struct btree_keys *b;
	#endif
		struct btree_iter_set {
			struct bkey *k, *end;
		} data[MAX_BSETS];
	};

We can see that the length of data[] field is static MAX_BSETS, which is
defined as 4 currently.

But a btree node on disk could have too many bsets for an iterator to fit
on the stack - maybe far more that MAX_BSETS. Have to dynamically allocate
space to host more btree_iter_sets.

bch_cache_set_alloc() will make sure the pool cache_set->fill_iter can
allocate an iterator equipped with enough room that can host
	(sb.bucket_size / sb.block_size)
btree_iter_sets, which is more than static MAX_BSETS.

bch_btree_node_read_done() will use that pool to allocate one iterator, to
host many bsets in one btree node.

Add more comment around cache_set->fill_iter to make code less confusing.
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

llow NVMF_OPT_NR_WRITE_QUEUES to describe additional write queues.  In
addition, implement .map_queues that will apply 2 queue maps for read
and write queue sets.

Note that with the separate queue map, HCTX_TYPE_READ will always use
nr_io_queues and HCTX_TYPE_DEFAULT will use nr_write_queues.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Allow NVMF_OPT_NR_WRITE_QUEUES to describe additional write queues.  In
addition, implement .map_queues that will apply 2 queue maps for read
and write queue sets.

Note that with the separate queue map, HCTX_TYPE_READ will always use
nr_io_queues and HCTX_TYPE_DEFAULT will use nr_write_queues.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This argument will specify how many I/O queues will be connected in
create_ctrl in addition to nr_io_queues. With this configuration, I/O
that carries payload from the host to the target, will use the default
hctx queue map, and I/O that involves target to host transfers will use
the read hctx queue map.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Will be used by nvme-rdma for queue map separation support.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Now that we have error log page implementation update smart log command
handler to provide number of error log entries in the lifetime of the
controller field.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Now that we have support for all the major parts of the target we add
a NVMe error log page handler so that host can read the log page.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds support for the file backend to populate the
error log entries. Here we map the errno to the NVMe status codes.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds the support for the block device backend to populate the
error log entries. Here we map the blk_status_t to the NVMe status.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds the support to maintain the error log page for admin
commands.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds the support to maintain the error log page for rdma
transport, we mainly focus here on the NVME_INVALID_FIELD errors.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds the support to maintain error log page for the fabrics
prop get, prop set, and admin connect commands. Here we also update the
discovery.c and add update set/get features and parse functions to
support error log page.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds the support to maintain error log page for the
nvmet-core.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds nvmet_req based interface to the nvmet-core so that
we can update the error log page. We update error log page in
the request completion path when status is not set to NVME_SC_SUCCESS.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds necessary fields in the target data structures to
support error log page. For a target controller, we add a new error log
field to maintain the error log, at any given point we maintain error
entries equal to NVMET_ERROR_LOG_SLOTS for each controller. In the
following patch, we also update the error log page entry in the I/O
completion path so we introduce a spinlock for synchronization of the
log.

For nvmet_req, we add a new field error_loc to hold the location of
the error in the command when the actual error occurs for each request
and a starting LBA if applicable.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds the NVMe error slot definition from the spec.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This is a preparation patch which removes the nvme common command cdw10
array and replace with individual fields. This is needed for the nvmet
error log page implementation make is error log page entry offset
assignment easier.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

When boxes are run near (or to) OOM, we have a problem with the discard
page allocation in nvme. If we fail allocating the special page, we
return busy, and it'll get retried. But since ordering is honored for
dispatch requests, we can keep retrying this same IO and failing. Behind
that IO could be requests that want to free memory, but they never get
the chance.

Allocate a fixed discard page per controller for a safe fallback, and use
that if the initial allocation fails.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>