In commit d0a21265df David Rientjes unified various archs'
module_alloc implementation (including x86) and removed the graduitous
shortcut for size == 0.
Then, in commit de7d2b567d, Joe Perches added a warning for
zero-length vmallocs, which can happen without kallsyms on modules
with no init sections (eg. zlib_deflate).
Fix this once and for all; the module code has to handle zero length
anyway, so get it right at the caller and remove the now-gratuitous
checks within the arch-specific module_alloc implementations.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42608
Reported-by: Conrad Kostecki <ConiKost@gmx.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
82fab442f5