Set kernel config:
CONFIG_BLK_DEV_LOOP=m
CONFIG_BLK_DEV_LOOP_MIN_COUNT=0
Do latter:
mknod loop0 b 7 0
exec 4<> loop0
Before commit e418de3abcda ("block: switch gendisk lookup to a simple
xarray"), open loop0 will success. lookup_gendisk will first use
base_probe to load module loop, and then the retry will call loop_probe
to prepare the loop disk. Finally open for this disk will success.
However, after this commit, we lose the retry logic, and open will fail
with ENXIO. Block device autoloading is deprecated and will be removed
soon, but maybe we should keep open success until we really remove it.
So, give a retry to fix it.
Fixes: e418de3abcda ("block: switch gendisk lookup to a simple xarray")
Signed-off-by: Yang Erkun <yangerkun@xxxxxxxxxx>
---
block/genhd.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index 79230c109fca..950fdabaef2e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -802,7 +802,10 @@ void blk_request_module(dev_t devt)
{
unsigned int major = MAJOR(devt);
struct blk_major_name **n;
+ int retry = 0;
+ int error;
+retry:
mutex_lock(&major_names_lock);
for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
if ((*n)->major == major && (*n)->probe) {
@@ -813,9 +816,16 @@ void blk_request_module(dev_t devt)
}
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));
+ if (retry++)
+ return;
+
+ error = request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt));
+ if (!error)
+ goto retry;
+
+ /* Make old-style 2.4 aliases work */
+ if (error > 0 && !request_module("block-major-%d", MAJOR(devt)))
+ goto retry;
}
#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */
--
2.46.1
