Re: [PATCH 2/3] mm, swap: distinguish a malformed swap entry from a dying device

[Pedro Falcato]

On Wed, Aug 12, 2026 at 03:48:56AM -0700, Breno Leitao wrote:
> Hello David,
> 
> On Tue, Aug 11, 2026 at 05:36:31PM +0200, David Hildenbrand (Arm) wrote:
> > On 8/10/26 18:26, Breno Leitao wrote:
> > > +	return ERR_PTR(-EINVAL);
> > >  }
> >
> > Is -EINVAL really the logical right return value? Running into bad swap entries
> > sounds more serious to me than "-EINVAL" :)
> 
> Good point, maybe we need a strong drug here, what about -EIO?
> 
> I picked -EINVAL because it is what the swap code already returns for
> this exact condition. 
> 
> 
> 	* Returns -EINVAL if the swap entry is invalid, which might
> 	* occur if a page table entry has got corrupted.
> 	*/
> 	int swap_dup_entry_direct(swp_entry_t entry)
> 	{
> 		si = swap_entry_to_info(entry);
> 		if (WARN_ON_ONCE(!si)) {
> 			pr_err("%s%08lx\n", Bad_file, entry.val);
> 			return -EINVAL;
> 
> But, I do agree -EINVAL is too soft given the situation we are in.
> 
> I will return -EIO in the next version, if I don't hear any concern.

Perhaps -EUCLEAN would be a more fitting error. It's generally what
filesystems use, at least (EFSCORRUPTED = EUCLEAN). 

-- 
Pedro