On Wed, Mar 20, 2019 at 04:19:59AM -0700, Matthew Wilcox wrote: > On Wed, Mar 20, 2019 at 03:35:38PM +0800, Baoquan He wrote: > > /* > > - * returns the number of sections whose mem_maps were properly > > - * set. If this is <=0, then that means that the passed-in > > - * map was not consumed and must be freed. > > + * sparse_add_one_section - add a memory section > > + * @nid: The node to add section on > > + * @start_pfn: start pfn of the memory range > > + * @altmap: device page map > > + * > > + * Return 0 on success and an appropriate error code otherwise. > > */ > > I think it's worth documenting what those error codes are. Seems to be > just -ENOMEM and -EEXIST, but it'd be nice for users to know what they > can expect under which circumstances. > > Also, -EEXIST is a bad errno to return here: > > $ errno EEXIST > EEXIST 17 File exists > > What file? I think we should be using -EBUSY instead in case this errno > makes it back to userspace: > > $ errno EBUSY > EBUSY 16 Device or resource busy We return -EEXIST in case the section we are trying to add is already there, and that error is being caught by __add_pages(), which ignores the error in case is -EXIST and keeps going with further sections. Sure we can change that for -EBUSY, but I think -EEXIST makes more sense, plus that kind of error is never handed back to userspace. -- Oscar Salvador SUSE L3
