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From: Bart Van Assche <bvanassche@acm.org>
To: Luis Chamberlain <mcgrof@kernel.org>,
	axboe@kernel.dk, viro@zeniv.linux.org.uk,
	gregkh@linuxfoundation.org, rostedt@goodmis.org,
	mingo@redhat.com, jack@suse.cz, ming.lei@redhat.com,
	nstange@suse.de, akpm@linux-foundation.org
Cc: mhocko@suse.com, yukuai3@huawei.com, martin.petersen@oracle.com,
	jejb@linux.ibm.com, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 7/8] blktrace: ensure our debugfs dir exists
Date: Sat, 20 Jun 2020 10:33:29 -0700	[thread overview]
Message-ID: <379e1fc9-a070-7730-71cd-aee7f582d403@acm.org> (raw)
In-Reply-To: <20200619204730.26124-8-mcgrof@kernel.org>

On 2020-06-19 13:47, Luis Chamberlain wrote:
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index e6e2d25fdbd6..098780ec018f 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -538,6 +538,18 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
>  #endif
>  		bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
>  
> +	/*
> +	 * As blktrace relies on debugfs for its interface the debugfs directory
> +	 * is required, contrary to the usual mantra of not checking for debugfs
> +	 * files or directories.
> +	 */
> +	if (IS_ERR_OR_NULL(dir)) {
> +		pr_warn("debugfs_dir not present for %s so skipping\n",
> +			buts->name);

Maybe mention in the message what is being skipped (block tracing)?

> +		ret = -ENOENT;
> +		goto err;
> +	}
> +
>  	bt->dev = dev;
>  	atomic_set(&bt->dropped, 0);
>  	INIT_LIST_HEAD(&bt->running_list);

Anyway:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>


  parent reply	other threads:[~2020-06-20 17:33 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-19 20:47 [PATCH v7 0/8] blktrace: fix debugfs use after free Luis Chamberlain
2020-06-19 20:47 ` [PATCH v7 1/8] block: add docs for gendisk / request_queue refcount helpers Luis Chamberlain
2020-06-19 20:47 ` [PATCH v7 2/8] block: clarify context for refcount increment helpers Luis Chamberlain
2020-06-19 20:47 ` [PATCH v7 3/8] block: revert back to synchronous request_queue removal Luis Chamberlain
2020-06-19 20:47 ` [PATCH v7 4/8] blktrace: annotate required lock on do_blk_trace_setup() Luis Chamberlain
2020-06-20 17:02   ` Bart Van Assche
2020-06-19 20:47 ` [PATCH v7 5/8] loop: be paranoid on exit and prevent new additions / removals Luis Chamberlain
2020-06-20 17:11   ` Bart Van Assche
2020-06-22 12:27     ` Luis Chamberlain
2020-06-23  2:16       ` Bart Van Assche
2020-06-23 16:56         ` Luis Chamberlain
2020-06-23 17:05       ` Johannes Thumshirn
2020-06-24 12:08         ` Luis Chamberlain
2020-06-19 20:47 ` [PATCH v7 6/8] blktrace: fix debugfs use after free Luis Chamberlain
2020-06-20  7:29   ` Christoph Hellwig
2020-06-20 17:31   ` Bart Van Assche
2020-06-22 12:36     ` Luis Chamberlain
2020-06-19 20:47 ` [PATCH v7 7/8] blktrace: ensure our debugfs dir exists Luis Chamberlain
2020-06-20  7:29   ` Christoph Hellwig
2020-06-20 17:33   ` Bart Van Assche [this message]
2020-06-19 20:47 ` [PATCH v7 8/8] block: create the request_queue debugfs_dir on registration Luis Chamberlain
2020-06-20  7:30   ` Christoph Hellwig
2020-06-20 18:07   ` Bart Van Assche
2020-06-22 12:42     ` Luis Chamberlain
2020-06-23  3:18       ` Bart Van Assche
2020-06-20 21:18 ` [PATCH v7 0/8] blktrace: fix debugfs use after free Jens Axboe

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