Make the legacy dev_t based autoloading optional and add a deprecation
warning. This kind of autoloading has ceased to be useful about 20 years
ago.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
Changes since v1:
- improve the Kconfig help text and deprecation printk
block/Kconfig | 12 ++++++++++++
block/bdev.c | 9 ++++++---
block/genhd.c | 6 ++++++
3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/block/Kconfig b/block/Kconfig
index d5d4197b7ed2d..205f8d01c6952 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -26,6 +26,18 @@ menuconfig BLOCK
if BLOCK
+config BLOCK_LEGACY_AUTOLOAD
+ bool "Legacy autoloading support"
+ help
+ Enable loading modules and creating block device instances based on
+ accesses through their device special file. This is a historic Linux
+ feature and makes no sense in a udev world where device files are
+ created on demand.
+
+ Say N here unless booting or other functionality broke without it, in
+ which case you should also send a report to your distribution and
+ linux-block@xxxxxxxxxxxxxxx.
+
config BLK_RQ_ALLOC_TIME
bool
diff --git a/block/bdev.c b/block/bdev.c
index 8bf93a19041b7..51e41b2da2d9f 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -738,12 +738,15 @@ struct block_device *blkdev_get_no_open(dev_t dev)
struct inode *inode;
inode = ilookup(blockdev_superblock, dev);
- if (!inode) {
+ if (!inode && IS_ENABLED(CONFIG_BLOCK_LEGACY_AUTOLOAD)) {
blk_request_module(dev);
inode = ilookup(blockdev_superblock, dev);
- if (!inode)
- return NULL;
+ if (inode)
+ pr_warn_ratelimited(
+"block device autoloading is deprecated. It will be removed in Linux 5.19\n");
}
+ if (!inode)
+ return NULL;
/* switch from the inode reference to a device mode one: */
bdev = &BDEV_I(inode)->bdev;
diff --git a/block/genhd.c b/block/genhd.c
index 626c8406f21a6..6ae990ff02660 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -185,7 +185,9 @@ static struct blk_major_name {
struct blk_major_name *next;
int major;
char name[16];
+#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
void (*probe)(dev_t devt);
+#endif
} *major_names[BLKDEV_MAJOR_HASH_SIZE];
static DEFINE_MUTEX(major_names_lock);
static DEFINE_SPINLOCK(major_names_spinlock);
@@ -275,7 +277,9 @@ int __register_blkdev(unsigned int major, const char *name,
}
p->major = major;
+#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
p->probe = probe;
+#endif
strlcpy(p->name, name, sizeof(p->name));
p->next = NULL;
index = major_to_index(major);
@@ -679,6 +683,7 @@ static ssize_t disk_badblocks_store(struct device *dev,
return badblocks_store(disk->bb, page, len, 0);
}
+#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
void blk_request_module(dev_t devt)
{
unsigned int major = MAJOR(devt);
@@ -698,6 +703,7 @@ void blk_request_module(dev_t devt)
/* Make old-style 2.4 aliases work */
request_module("block-major-%d", MAJOR(devt));
}
+#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */
/*
* print a full list of all partitions - intended for places where the root
--
2.30.2
