Commit 7427c30b authored Jan 24, 2023 by Jason Gunthorpe Committed by Andrew Morton Feb 09, 2023

mm/gup: remove obsolete FOLL_LONGTERM comment

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.

Link: https://lkml.kernel.org/r/2-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com


Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent b2a72dff

include/linux/mm_types.h

+0 −6

Original line number	Diff line number	Diff line
		@@ -1053,12 +1053,6 @@ 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.