[PATCH v7 2/8] block: clarify context for refcount increment helpers

Luis Chamberlain
2020-06-19T20:47:42Z

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