On 8/27/26 09:49, Mike Rapoport wrote:
> On Mon, Aug 24, 2026 at 04:46:14PM +0200, David Hildenbrand (Arm) wrote:
>> On 8/23/26 14:17, Mike Rapoport (Microsoft) wrote:
>>> Introduce enum uffd_reason to define reasons for user faults rather than
>>> overload VM_UFFD_* VMA flags for that.
>>>
>>> Using a dedicated enum makes the code clearer and decoupling the fault
>>> reason from VMA flags clears the way for moving the uffd mode bits out
>>> of VMA namespace.
>>>
>>> No functional change.
>>>
>>> Assisted-by: copilot:claude-opus-4.6
>>> Signed-off-by: Mike Rapoport (Microsoft) <[email protected]>
>>> ---
>>> include/linux/userfaultfd_k.h | 16 ++++++++++++++--
>>> include/uapi/linux/userfaultfd.h | 6 +++---
>>> mm/huge_memory.c | 6 +++---
>>> mm/hugetlb.c | 10 +++++-----
>>> mm/memory.c | 10 +++++-----
>>> mm/shmem.c | 4 ++--
>>> mm/userfaultfd.c | 30 +++++++++++++++---------------
>>> 7 files changed, 47 insertions(+), 35 deletions(-)
>>>
>>> diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
>>> index 45355bdb4ec7..f401623f315d 100644
>>> --- a/include/linux/userfaultfd_k.h
>>> +++ b/include/linux/userfaultfd_k.h
>>> @@ -9,6 +9,18 @@
>>> #ifndef _LINUX_USERFAULTFD_K_H
>>> #define _LINUX_USERFAULTFD_K_H
>>>
>>> +#include <linux/bits.h>
>>> +
>>> +/* Fault reason #PF handler passes to handle_userfault() */
>>> +enum uf_reason {
>>
>> Can we just call this "userfault_reason" or "uffd_reason" ? Maybe the latter
>> is
>> actually what we want?
>
> userfault_reason sounds better to me.
>
> It describes what kind of user fault we are handling and the 'fd' part has
> nothing to do with it.
> We do use uffd as a short name for the subsystem, but still most if not all
> userfaultfd "external" APIs use userfault_ prefix.
>
> uf_ was an attempt to make it wee shorter :)
Yeah, I got that; while uffd is a known acronym, the uf_ not so much (and also I
wouldn't suggest it to become a thing, lol :) )
I've been wondering for a while whether it really should be called
handle_userfault()
And not instead
handle_userfaultfd()
Or maybe even better
handle_uffd_fault()
And then have
uffd_fault_reason
... but just a thought.
--
Cheers,
David
