bdev_get_queue() never returns NULL. Several commits [1][2] have been made
before to remove such superfluous checks, but some still remained.

For places where bdev_get_queue() is called solely for NULL checks, it is
removed entirely.

[1] commit ec9fd2a13d74 ("blk-lib: don't check bdev_get_queue() NULL check")
[2] commit fea127b36c93 ("block: remove superfluous check for request queue in bdev_is_zoned()")

Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/r/20230203024029.48260-1-qkrwngud825@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230202141956.2299521-1-gregkh@linuxfoundation.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When the blk_classic option is enabled, non-blktrace events must be
filtered out. Otherwise, events of other types are output in the blktrace
classic format, which is unexpected.

The problem can be triggered in the following ways:

  # echo 1 > /sys/kernel/debug/tracing/options/blk_classic
  # echo 1 > /sys/kernel/debug/tracing/events/enable
  # echo blk > /sys/kernel/debug/tracing/current_tracer
  # cat /sys/kernel/debug/tracing/trace_pipe

Fixes: c71a89615411 ("blktrace: add ftrace plugin")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Link: https://lore.kernel.org/r/20221122040410.85113-1-yangjihong1@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use only one hyphen in kernel-doc notation between the function name
and its short description.

The is the documented kerenl-doc format. It also fixes the HTML
presentation to be consistent with other functions.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Link: https://lore.kernel.org/r/20221201070331.25685-1-rdunlap@infradead.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

As previous commit, 'blk_trace_cleanup' will stop block trace if
block trace's state is 'Blktrace_running'.
So remove unnessary stop block trace in 'blk_trace_shutdown'.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019033602.752383-4-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When test as follows:
step1: ioctl(sda, BLKTRACESETUP, &arg)
step2: ioctl(sda, BLKTRACESTART, NULL)
step3: ioctl(sda, BLKTRACETEARDOWN, NULL)
step4: ioctl(sda, BLKTRACESETUP, &arg)
Got issue as follows:
debugfs: File 'dropped' in directory 'sda' already present!
debugfs: File 'msg' in directory 'sda' already present!
debugfs: File 'trace0' in directory 'sda' already present!

And also find syzkaller report issue like "KASAN: use-after-free Read in relay_switch_subbuf"
"https://syzkaller.appspot.com/bug?id=13849f0d9b1b818b087341691be6cc3ac6a6bfb7"

If remove block trace without stop(BLKTRACESTOP) block trace, '__blk_trace_remove'
will just set 'q->blk_trace' with NULL. However, debugfs file isn't removed, so
will report file already present when call BLKTRACESETUP.
static int __blk_trace_remove(struct request_queue *q)
{
        struct blk_trace *bt;

        bt = rcu_replace_pointer(q->blk_trace, NULL,
                                 lockdep_is_held(&q->debugfs_mutex));
        if (!bt)
                return -EINVAL;

	if (bt->trace_state != Blktrace_running)
        	blk_trace_cleanup(q, bt);

        return 0;
}

If do test as follows:
step1: ioctl(sda, BLKTRACESETUP, &arg)
step2: ioctl(sda, BLKTRACESTART, NULL)
step3: ioctl(sda, BLKTRACETEARDOWN, NULL)
step4: remove sda

There will remove debugfs directory which will remove recursively all file
under directory.
>> blk_release_queue
>>	debugfs_remove_recursive(q->debugfs_dir)
So all files which created in 'do_blk_trace_setup' are removed, and
'dentry->d_inode' is NULL. But 'q->blk_trace' is still in 'running_trace_lock',
'trace_note_tsk' will traverse 'running_trace_lock' all nodes.
>>trace_note_tsk
>>  trace_note
>>    relay_reserve
>>       relay_switch_subbuf
>>        d_inode(buf->dentry)->i_size

To solve above issues, reference commit '5afedf670caf', call 'blk_trace_cleanup'
unconditionally in '__blk_trace_remove' and first stop block trace in
'blk_trace_cleanup'.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019033602.752383-3-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Introduce 'blk_trace_{start,stop}' helper. No functional changed.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019033602.752383-2-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Reflect recent changes in the blk_fill_rwbs() kernel-doc header.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 919dbca8670d ("blktrace: Use the new blk_opf_t type")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220715184735.2326034-3-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Improve static type checking by using the new blk_opf_t type for a function
argument that represents a combination of a request operation and request
flags. Rename that argument from 'op' into 'opf' to make its role more
clear.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-12-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Trace the remapped operation and its flags instead of only the data
direction of remapped operations. This issue was detected by analyzing
the warnings reported by sparse related to the new blk_opf_t type.

Reviewed-by: Jun'ichi Nomura <junichi.nomura@nec.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Fixes: 1b9a9ab78b0a ("blktrace: use op accessors")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-11-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>