From 2c2241081f7dec878331fdc3a3f2361e99556bca Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Tue, 24 Jan 2023 16:34:34 -0400 Subject: [PATCH] mm/gup: move private gup FOLL_ flags to internal.h Move the flags that should not/are not used outside gup.c and related into mm/internal.h to discourage driver abuse. To make this more maintainable going forward compact the two FOLL ranges with new bit numbers from 0 to 11 and 16 to 21, using shifts so it is explicit. Switch to an enum so the whole thing is easier to read. Link: https://lkml.kernel.org/r/13-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe Reviewed-by: John Hubbard Acked-by: David Hildenbrand Cc: David Howells Cc: Christoph Hellwig Cc: Claudio Imbrenda Cc: Alistair Popple Cc: Mike Rapoport (IBM) Signed-off-by: Andrew Morton --- include/linux/mm_types.h | 57 +++++++++++++++++++++++++++++------------------- mm/internal.h | 15 +++++++++++++ 2 files changed, 50 insertions(+), 22 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 434b3ac..56753d0 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1040,9 +1040,6 @@ typedef unsigned int __bitwise zap_flags_t; * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each * other. Here is what they mean, and how to use them: * - * FOLL_LONGTERM indicates that the page will be held for an indefinite time - * period _often_ under userspace control. This is in contrast to - * iov_iter_get_pages(), whose usages are transient. * * FIXME: For pages which are part of a filesystem, mappings are subject to the * lifetime enforced by the filesystem and we need guarantees that longterm @@ -1086,24 +1083,40 @@ typedef unsigned int __bitwise zap_flags_t; * Please see Documentation/core-api/pin_user_pages.rst for more information. */ -#define FOLL_WRITE 0x01 /* check pte is writable */ -#define FOLL_TOUCH 0x02 /* mark page accessed */ -#define FOLL_GET 0x04 /* do get_page on page */ -#define FOLL_DUMP 0x08 /* give error on hole if it would be zero */ -#define FOLL_FORCE 0x10 /* get_user_pages read/write w/o permission */ -#define FOLL_NOWAIT 0x20 /* if a disk transfer is needed, start the IO - * and return without waiting upon it */ -#define FOLL_NOFAULT 0x80 /* do not fault in pages */ -#define FOLL_HWPOISON 0x100 /* check page is hwpoisoned */ -#define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */ -#define FOLL_REMOTE 0x2000 /* we are working on non-current tsk/mm */ -#define FOLL_ANON 0x8000 /* don't do file mappings */ -#define FOLL_LONGTERM 0x10000 /* mapping lifetime is indefinite: see below */ -#define FOLL_SPLIT_PMD 0x20000 /* split huge pmd before returning */ -#define FOLL_PIN 0x40000 /* pages must be released via unpin_user_page */ -#define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ -#define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */ -#define FOLL_INTERRUPTIBLE 0x200000 /* allow interrupts from generic signals */ -#define FOLL_UNLOCKABLE 0x400000 /* allow unlocking the mmap lock (internal only) */ +enum { + /* check pte is writable */ + FOLL_WRITE = 1 << 0, + /* do get_page on page */ + FOLL_GET = 1 << 1, + /* give error on hole if it would be zero */ + FOLL_DUMP = 1 << 2, + /* get_user_pages read/write w/o permission */ + FOLL_FORCE = 1 << 3, + /* + * if a disk transfer is needed, start the IO and return without waiting + * upon it + */ + FOLL_NOWAIT = 1 << 4, + /* do not fault in pages */ + FOLL_NOFAULT = 1 << 5, + /* check page is hwpoisoned */ + FOLL_HWPOISON = 1 << 6, + /* don't do file mappings */ + FOLL_ANON = 1 << 7, + /* + * FOLL_LONGTERM indicates that the page will be held for an indefinite + * time period _often_ under userspace control. This is in contrast to + * iov_iter_get_pages(), whose usages are transient. + */ + FOLL_LONGTERM = 1 << 8, + /* split huge pmd before returning */ + FOLL_SPLIT_PMD = 1 << 9, + /* allow returning PCI P2PDMA pages */ + FOLL_PCI_P2PDMA = 1 << 10, + /* allow interrupts from generic signals */ + FOLL_INTERRUPTIBLE = 1 << 11, + + /* See also internal only FOLL flags in mm/internal.h */ +}; #endif /* _LINUX_MM_TYPES_H */ diff --git a/mm/internal.h b/mm/internal.h index 4f5ca34..dfb37e9 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -858,6 +858,21 @@ int migrate_device_coherent_page(struct page *page); struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags); int __must_check try_grab_page(struct page *page, unsigned int flags); +enum { + /* mark page accessed */ + FOLL_TOUCH = 1 << 16, + /* a retry, previous pass started an IO */ + FOLL_TRIED = 1 << 17, + /* we are working on non-current tsk/mm */ + FOLL_REMOTE = 1 << 18, + /* pages must be released via unpin_user_page */ + FOLL_PIN = 1 << 19, + /* gup_fast: prevent fall-back to slow gup */ + FOLL_FAST_ONLY = 1 << 20, + /* allow unlocking the mmap lock */ + FOLL_UNLOCKABLE = 1 << 21, +}; + /* * Indicates for which pages that are write-protected in the page table, * whether GUP has to trigger unsharing via FAULT_FLAG_UNSHARE such that the -- 2.7.4