[PATCH 06/19] block: add an optional probe callback to major_names
From: Christoph Hellwig <hch@lst.de>
Date: 2020-08-30 06:27:42
Also in:
linux-block, linux-ide, linux-m68k, linux-scsi, lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Add a callback to the major_names array that allows a driver to override how to probe for dev_t that doesn't currently have a gendisk registered. This will help separating the lookup of the gendisk by dev_t vs probe action for a not currently registered dev_t. Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/genhd.c | 21 ++++++++++++++++++--- include/linux/genhd.h | 5 ++++- 2 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index 00164304317cfa..4cbeff3ec1ef5a 100644
--- a/block/genhd.c
+++ b/block/genhd.c@@ -402,6 +402,7 @@ static struct blk_major_name { struct blk_major_name *next; int major; char name[16]; + void (*probe)(dev_t devt); } *major_names[BLKDEV_MAJOR_HASH_SIZE]; static DEFINE_MUTEX(major_names_lock);
@@ -444,7 +445,8 @@ void blkdev_show(struct seq_file *seqf, off_t offset) * See Documentation/admin-guide/devices.txt for the list of allocated * major numbers. */ -int register_blkdev(unsigned int major, const char *name) +int __register_blkdev(unsigned int major, const char *name, + void (*probe)(dev_t devt)) { struct blk_major_name **n, *p; int index, ret = 0;
@@ -483,6 +485,7 @@ int register_blkdev(unsigned int major, const char *name) } p->major = major; + p->probe = probe; strlcpy(p->name, name, sizeof(p->name)); p->next = NULL; index = major_to_index(major);
@@ -505,8 +508,7 @@ int register_blkdev(unsigned int major, const char *name) mutex_unlock(&major_names_lock); return ret; } - -EXPORT_SYMBOL(register_blkdev); +EXPORT_SYMBOL(__register_blkdev); void unregister_blkdev(unsigned int major, const char *name) {
@@ -1037,6 +1039,19 @@ static ssize_t disk_badblocks_store(struct device *dev, static void request_gendisk_module(dev_t devt) { + unsigned int major = MAJOR(devt); + struct blk_major_name **n; + + mutex_lock(&major_names_lock); + for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) { + if ((*n)->major == major && (*n)->probe) { + (*n)->probe(devt); + mutex_unlock(&major_names_lock); + return; + } + } + mutex_unlock(&major_names_lock); + if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) /* Make old-style 2.4 aliases work */ request_module("block-major-%d", MAJOR(devt));
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 4ab853461dff25..c0bde190a3dd0c 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h@@ -369,7 +369,10 @@ extern void blk_unregister_region(dev_t devt, unsigned long range); #define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE) -int register_blkdev(unsigned int major, const char *name); +int __register_blkdev(unsigned int major, const char *name, + void (*probe)(dev_t devt)); +#define register_blkdev(major, name) \ + __register_blkdev(major, name, NULL) void unregister_blkdev(unsigned int major, const char *name); int revalidate_disk(struct gendisk *disk);
--
2.28.0