6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yang Erkun yangerkun@huawei.com
[ Upstream commit 457ef47c08d2979f3e59ce66267485c3faed70c8 ]
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"), 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") Suggested-by: Christoph Hellwig hch@lst.de Signed-off-by: Yang Erkun yangerkun@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20241209110435.3670985-1-yangerkun@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/genhd.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c index 8645cf3b0816e..99344f53c7897 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -778,7 +778,7 @@ static ssize_t disk_badblocks_store(struct device *dev, }
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD -void blk_request_module(dev_t devt) +static bool blk_probe_dev(dev_t devt) { unsigned int major = MAJOR(devt); struct blk_major_name **n; @@ -788,14 +788,26 @@ void blk_request_module(dev_t devt) if ((*n)->major == major && (*n)->probe) { (*n)->probe(devt); mutex_unlock(&major_names_lock); - return; + return true; } } mutex_unlock(&major_names_lock); + return false; +} + +void blk_request_module(dev_t devt) +{ + int error; + + if (blk_probe_dev(devt)) + return;
- 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)); + error = request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)); + /* Make old-style 2.4 aliases work */ + if (error > 0) + error = request_module("block-major-%d", MAJOR(devt)); + if (!error) + blk_probe_dev(devt); } #endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */