[PATCH 05/26] block: add blk_alloc_disk and blk_cleanup_disk APIs

Christoph Hellwig
2021-05-21T05:51:59Z

Add two new APIs to allocate and free a gendisk including the
request_queue for use with BIO based drivers. This is to avoid
boilerplate code in drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/genhd.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/genhd.h | 22 ++++++++++++++++++++++
2 files changed, 57 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index e4974af3d729..6d4ce962866d 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1302,6 +1302,25 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
}
EXPORT_SYMBOL(__alloc_disk_node);

+struct gendisk *__blk_alloc_disk(int node)
+{
+ struct request_queue *q;
+ struct gendisk *disk;
+
+ q = blk_alloc_queue(node);
+ if (!q)
+ return NULL;
+
+ disk = __alloc_disk_node(0, node);
+ if (!disk) {
+ blk_cleanup_queue(q);
+ return NULL;
+ }
+ disk->queue = q;
+ return disk;
+}
+EXPORT_SYMBOL(__blk_alloc_disk);
+
/**
* put_disk - decrements the gendisk refcount
* @disk: the struct gendisk to decrement the refcount for
@@ -1319,6 +1338,22 @@ void put_disk(struct gendisk *disk)
}
EXPORT_SYMBOL(put_disk);

+/**
+ * blk_cleanup_disk - shutdown a gendisk allocated by blk_alloc_disk
+ * @disk: gendisk to shutdown
+ *
+ * Mark the queue hanging off @disk DYING, drain all pending requests, then mark
+ * the queue DEAD, destroy and put it and the gendisk structure.
+ *
+ * Context: can sleep
+ */
+void blk_cleanup_disk(struct gendisk *disk)
+{
+ blk_cleanup_queue(disk->queue);
+ put_disk(disk);
+}
+EXPORT_SYMBOL(blk_cleanup_disk);
+
static void set_disk_ro_uevent(struct gendisk *gd, int ro)
{
char event[] = "DISK_RO=1";
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index a5443f0b139d..03aa12730634 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -278,6 +278,28 @@ extern void put_disk(struct gendisk *disk);

#define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE)

+/**
+ * blk_alloc_disk - allocate a gendisk structure
+ * @node_id: numa node to allocate on
+ *
+ * Allocate and pre-initialize a gendisk structure for use with BIO based
+ * drivers.
+ *
+ * Context: can sleep
+ */
+#define blk_alloc_disk(node_id) \
+({ \
+ struct gendisk *__disk = __blk_alloc_disk(node_id); \
+ static struct lock_class_key __key; \
+ \
+ if (__disk) \
+ lockdep_init_map(&__disk->lockdep_map, \
+ "(bio completion)", &__key, 0); \
+ __disk; \
+})
+struct gendisk *__blk_alloc_disk(int node);
+void blk_cleanup_disk(struct gendisk *disk);
+
int __register_blkdev(unsigned int major, const char *name,
void (*probe)(dev_t devt));
#define register_blkdev(major, name) \
--
2.30.2