Hello,
It seems thare are many places where code assumes iounmap(NULL) is safe.
Also there are several patches that state it explicitly:
ff6defa6a8fa ("ALSA: Deletion of checks before the function call "iounmap")
e24bb0ed8179 ("staging: dgnc: remove NULL test")
At the same time it seems PPC implementation generates a warning in this case:
3bfafd6b136b ("netxen: avoid invalid iounmap")
arch/powerpc/mm/pgtable_64.c:
if ((unsigned long)addr < ioremap_bot) {
printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
" at 0x%p\n", addr);
return;
}
Could you please clarify if iounmap(NULL) safe or not.
I guess it would be less errorprone if the answer is architecture independent.
--
Thank you,
Alexey Khoroshilov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
