Messages in this thread Patch in this message | | | From | Luis Chamberlain <> | Subject | [PATCH v5 11/14] block: update __register_blkdev() probe documentation | Date | Wed, 3 Nov 2021 16:04:34 -0700 |
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__register_blkdev() is used to register a probe callback, and that callback is typically used to call add_disk(). Now that we are able to capture errors for add_disk(), we need to fix those probe calls where add_disk() fails and clean up resources.
We don't extend the probe call to return the error given:
1) we'd have to always special-case the case where the disk was already present, as otherwise concurrent requests to open an existing block device would fail, and this would be a userspace visible change 2) the error from ilookup() on blkdev_get_no_open() is sufficient 3) The only thing the probe call is used for is to support pre-devtmpfs, pre-udev semantics that want to create disks when their pre-created device node is accessed, and so we don't care for failures on probe there.
Expand documentation for the probe callback to ensure users cleanup resources if add_disk() is used and to clarify this interface may be removed in the future.
Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> --- block/genhd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/block/genhd.c b/block/genhd.c index 4ed87f25276a..2f5b7e24e88a 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -213,7 +213,10 @@ void blkdev_show(struct seq_file *seqf, off_t offset) * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If * @major = 0, try to allocate any unused major number. * @name: the name of the new block device as a zero terminated string - * @probe: allback that is called on access to any minor number of @major + * @probe: pre-devtmpfs / pre-udev callback used to create disks when their + * pre-created device node is accessed. When a probe call uses + * add_disk() and it fails the driver must cleanup resources. This + * interface may soon be removed. * * The @name must be unique within the system. * -- 2.33.0
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