diff mbox series

[v2,02/13] mm/gup: remove obsolete FOLL_LONGTERM comment

Message ID 2-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com (mailing list archive)
State New
Headers show
Series Simplify the external interface for GUP | expand

Commit Message

Jason Gunthorpe Jan. 24, 2023, 8:34 p.m. UTC
These days FOLL_LONGTERM is not allowed at all on any get_user_pages*()
functions, it must be only be used with pin_user_pages*(), plus it now has
universal support for all the pin_user_pages*() functions.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 include/linux/mm_types.h | 6 ------
 1 file changed, 6 deletions(-)

Comments

John Hubbard Jan. 25, 2023, 2:13 a.m. UTC | #1
On 1/24/23 12:34, Jason Gunthorpe wrote:
> These days FOLL_LONGTERM is not allowed at all on any get_user_pages*()
> functions, it must be only be used with pin_user_pages*(), plus it now has
> universal support for all the pin_user_pages*() functions.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>   include/linux/mm_types.h | 6 ------
>   1 file changed, 6 deletions(-)

Yes! Progress has happened.

Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
David Hildenbrand Feb. 8, 2023, 2:25 p.m. UTC | #2
On 24.01.23 21:34, Jason Gunthorpe wrote:
> These days FOLL_LONGTERM is not allowed at all on any get_user_pages*()
> functions, it must be only be used with pin_user_pages*(), plus it now has
> universal support for all the pin_user_pages*() functions.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>   include/linux/mm_types.h | 6 ------
>   1 file changed, 6 deletions(-)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index a689198caf7408..8971a40c120e38 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -1052,12 +1052,6 @@ typedef unsigned int __bitwise zap_flags_t;
>    * specifically failed.  Filesystem pages are still subject to bugs and use of
>    * FOLL_LONGTERM should be avoided on those pages.
>    *
> - * FIXME: Also NOTE that FOLL_LONGTERM is not supported in every GUP call.
> - * Currently only get_user_pages() and get_user_pages_fast() support this flag
> - * and calls to get_user_pages_[un]locked are specifically not allowed.  This
> - * is due to an incompatibility with the FS DAX check and
> - * FAULT_FLAG_ALLOW_RETRY.
> - *
>    * In the CMA case: long term pins in a CMA region would unnecessarily fragment
>    * that region.  And so, CMA attempts to migrate the page before pinning, when
>    * FOLL_LONGTERM is specified.

Reviewed-by: David Hildenbrand <david@redhat.com>
diff mbox series

Patch

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index a689198caf7408..8971a40c120e38 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -1052,12 +1052,6 @@  typedef unsigned int __bitwise zap_flags_t;
  * specifically failed.  Filesystem pages are still subject to bugs and use of
  * FOLL_LONGTERM should be avoided on those pages.
  *
- * FIXME: Also NOTE that FOLL_LONGTERM is not supported in every GUP call.
- * Currently only get_user_pages() and get_user_pages_fast() support this flag
- * and calls to get_user_pages_[un]locked are specifically not allowed.  This
- * is due to an incompatibility with the FS DAX check and
- * FAULT_FLAG_ALLOW_RETRY.
- *
  * In the CMA case: long term pins in a CMA region would unnecessarily fragment
  * that region.  And so, CMA attempts to migrate the page before pinning, when
  * FOLL_LONGTERM is specified.