From a7da811215cd563a3389769d93b0f7d6cdb9bffe Mon Sep 17 00:00:00 2001 From: Yang Erkun Date: Mon, 9 Dec 2024 19:04:35 +0800 Subject: [PATCH] block: retry call probe after request_module in blk_request_module [ 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 Signed-off-by: Yang Erkun Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241209110435.3670985-1-yangerkun@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/genhd.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 8256e11f85b7..1cb517969607 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -738,7 +738,7 @@ 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; @@ -748,14 +748,26 @@ 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; +} - 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)); +void blk_request_module(dev_t devt) +{ + int error; + + if (blk_probe_dev(devt)) + return; + + 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 */