block: don't return -EINVAL for not found names in devt_from_devname

When we didn't find a device and didn't guess it might be a partition,
it might still show up later, so don't disable rootwait for it by
returning -EINVAL.

Fixes: 079caa35f786 ("init: clear root_wait on all invalid root= strings")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230622150644.600327-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Improve kernel-doc headers

Fix the documentation of the devt_from_partuuid() return value.

Fix the following two recently introduced kernel-doc warnings:

block/bdev.c:570: warning: Function parameter or member 'hops' not described in 'bd_finish_claiming'
block/early-lookup.c:46: warning: Function parameter or member 'devt' not described in 'devt_from_partuuid'

Cc: Christoph Hellwig <hch@lst.de>
Fixes: 0718afd47f70 ("block: introduce holder ops")
Fixes: cf056a431215 ("init: improve the name_to_dev_t interface")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230621165054.743815-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix rootwait= again

The previous rootwait fix added an -EINVAL return to a completely
bogus superflous branch, fix this.

Fixes: 1341c7d2ccf4 ("block: fix rootwait=")
Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Fabio Estevam <festevam@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230609051737.328930-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix rootwait=

Failures to look up the gendisk must return -ENODEV so that rootwait
retries the lookup instead of -EINVAL which exits early.

Fixes: cf056a431215 ("init: improve the name_to_dev_t interface")
Reported-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20230607135746.92995-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: mark early_lookup_bdev as __init

early_lookup_bdev is now only used during the early boot code as it
should, so mark it __init to not waste run time memory on it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-25-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move more code to early-lookup.c

blk_lookup_devt is only used by code in early-lookup.c, so move it
there.

printk_all_partitions and it's helper bdevt_str are only used by the
early init code in init/do_mounts.c, so they should go there as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move the code to do early boot lookup of block devices to block/

Create a new block/early-lookup.c to keep the early block device lookup
code instead of having this code sit with the early mount code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>