Commit a7a20d1039 ("sd: limit the scope of the async probe domain")
make the SCSI device probing run device discovery in it's own async
domain.
However, as a result, the partition detection was no longer synchronized
by async_synchronize_full() (which, despite the name, only synchronizes
the global async space, not all of them). Which in turn meant that
"wait_for_device_probe()" would not wait for the SCSI partitions to be
parsed.
And "wait_for_device_probe()" was what the boot time init code relied on
for mounting the root filesystem.
Now, most people never noticed this, because not only is it
timing-dependent, but modern distributions all use initrd. So the root
filesystem isn't actually on a disk at all. And then before they
actually mount the final disk filesystem, they will have loaded the
scsi-wait-scan module, which not only does the expected
wait_for_device_probe(), but also does scsi_complete_async_scans().
[ Side note: scsi_complete_async_scans() had also been partially broken,
but that was fixed in commit 43a8d39d01 ("fix async probe
regression"), so that same commit a7a20d1039 had actually broken
setups even if you used scsi-wait-scan explicitly ]
Solve this problem by just moving the scsi_complete_async_scans() call
into wait_for_device_probe(). Everybody who wants to wait for device
probing to finish really wants the SCSI probing to complete, so there's
no reason not to do this.
So now "wait_for_device_probe()" really does what the name implies, and
properly waits for device probing to finish. This also removes the now
unnecessary extra calls to scsi_complete_async_scans().
Reported-and-tested-by: Artem S. Tashkinov <t.artem@mailcity.com>
Cc: Dan Williams <dan.j.williams@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: linux-scsi <linux-scsi@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
