diff options
| author | David Hildenbrand <david@redhat.com> | 2023-01-02 17:08:55 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-01-18 17:12:57 -0800 |
| commit | b6b7a8faf05c709cd9f63d3b7d9c66bd91bc3b0d (patch) | |
| tree | e9314f6d0ce7fd59966ee70989134666ed5b477a /include/linux/mm.h | |
| parent | fc4f4be9b5271e43eeb4c675d190fa9734de9ea3 (diff) | |
| download | linux-next-b6b7a8faf05c709cd9f63d3b7d9c66bd91bc3b0d.tar.gz | |
mm/nommu: don't use VM_MAYSHARE for MAP_PRIVATE mappings
Let's stop using VM_MAYSHARE for MAP_PRIVATE mappings and use
VM_MAYOVERLAY instead. Rewrite determine_vm_flags() to make the whole
logic easier to digest, and to cleanly separate MAP_PRIVATE vs.
MAP_SHARED.
No functional change intended.
Link: https://lkml.kernel.org/r/20230102160856.500584-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 791bac40bf8e..8a8563359946 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -276,7 +276,12 @@ extern unsigned int kobjsize(const void *objp); #define VM_MAYSHARE 0x00000080 #define VM_GROWSDOWN 0x00000100 /* general info on the segment */ +#ifdef CONFIG_MMU #define VM_UFFD_MISSING 0x00000200 /* missing pages tracking */ +#else /* CONFIG_MMU */ +#define VM_MAYOVERLAY 0x00000200 /* nommu: R/O MAP_PRIVATE mapping that might overlay a file mapping */ +#define VM_UFFD_MISSING 0 +#endif /* CONFIG_MMU */ #define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */ #define VM_UFFD_WP 0x00001000 /* wrprotect pages tracking */ @@ -1358,7 +1363,7 @@ static inline bool is_nommu_shared_mapping(vm_flags_t flags) * ptrace does not apply. Note that there is no mprotect() to upgrade * write permissions later. */ - return flags & VM_MAYSHARE; + return flags & (VM_MAYSHARE | VM_MAYOVERLAY); } #endif |