module: make waiting for a concurrent module loader interruptible

module: make waiting for a concurrent module loader interruptible

The recursive aes-arm-bs module load situation reported by Russell King
is getting fixed in the crypto layer, but this in the meantime fixes the
"recursive load hangs forever" by just making the waiting for the first
module load be interruptible.

This should now match the old behavior before commit 9b9879fc0327
("modules: catch concurrent module loads, treat them as idempotent"),
which used the different "wait for module to be ready" code in
module_patient_check_exists().

End result: a recursive module load will still block, but now a signal
will interrupt it and fail the second module load, at which point the
first module will successfully complete loading.

Fixes: 9b9879fc0327 ("modules: catch concurrent module loads, treat them as idempotent")
Cc: Russell King <linux@armlinux.org.uk>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>