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From: Luis Chamberlain <mcgrof@kernel.org>
To: axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org,
	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,
	Luis Chamberlain <mcgrof@kernel.org>,
	Christoph Hellwig <hch@lst.de>
Subject: [PATCH v6 2/6] block: clarify context for refcount increment helpers
Date: Mon,  8 Jun 2020 17:01:22 +0000	[thread overview]
Message-ID: <20200608170127.20419-3-mcgrof@kernel.org> (raw)
In-Reply-To: <20200608170127.20419-1-mcgrof@kernel.org>

Let us clarify the context under which the helpers to increment the
refcount for the gendisk and request_queue can be called under. We
make this explicit on the places where we may sleep with might_sleep().

We don't address the decrement context yet, as that needs some extra
work and fixes, but will be addressed in the next patch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 block/blk-core.c | 2 ++
 block/genhd.c    | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index a0760aac110a..14c09daf55f3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -610,6 +610,8 @@ EXPORT_SYMBOL(blk_alloc_queue);
  * @q: the request_queue structure to increment the refcount for
  *
  * Increment the refcount of the request_queue kobject.
+ *
+ * Context: Any context.
  */
 bool blk_get_queue(struct request_queue *q)
 {
diff --git a/block/genhd.c b/block/genhd.c
index f741613d731f..1be86b1f43ec 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -985,11 +985,15 @@ static ssize_t disk_badblocks_store(struct device *dev,
  *
  * This function gets the structure containing partitioning
  * information for the given device @devt.
+ *
+ * Context: can sleep
  */
 struct gendisk *get_gendisk(dev_t devt, int *partno)
 {
 	struct gendisk *disk = NULL;
 
+	might_sleep();
+
 	if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
 		struct kobject *kobj;
 
@@ -1764,6 +1768,8 @@ EXPORT_SYMBOL(__alloc_disk_node);
  *
  * This increments the refcount for the struct gendisk, and the gendisk's
  * fops module owner.
+ *
+ * Context: Any context.
  */
 struct kobject *get_disk_and_module(struct gendisk *disk)
 {
-- 
2.26.2


  parent reply	other threads:[~2020-06-08 17:02 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-08 17:01 [PATCH v6 0/8] block: fix blktrace debugfs use after free Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 1/6] block: add docs for gendisk / request_queue refcount helpers Luis Chamberlain
2020-06-08 17:01 ` Luis Chamberlain [this message]
2020-06-08 17:01 ` [PATCH v6 3/6] block: revert back to synchronous request_queue removal Luis Chamberlain
2020-06-13  1:53   ` Bart Van Assche
2020-06-19 20:23     ` Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 4/6] blktrace: annotate required lock on do_blk_trace_setup() Luis Chamberlain
2020-06-09 14:18   ` Christoph Hellwig
2020-06-13  1:54   ` Bart Van Assche
2020-06-08 17:01 ` [PATCH v6 5/6] loop: be paranoid on exit and prevent new additions / removals Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 6/6] blktrace: fix debugfs use after free Luis Chamberlain
2020-06-09 15:06   ` Christoph Hellwig
2020-06-09 17:29     ` Luis Chamberlain
2020-06-09 17:32       ` Christoph Hellwig
2020-06-09 17:53         ` Luis Chamberlain
2020-06-10  6:42           ` Christoph Hellwig
2020-06-10 21:09             ` Luis Chamberlain
2020-06-10 21:52               ` Luis Chamberlain
2020-06-10 23:31                 ` Luis Chamberlain
2020-06-11  5:40                   ` Christoph Hellwig
2020-06-13  2:42   ` Bart Van Assche
2020-06-19 15:36     ` Luis Chamberlain

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