Re: [PATCH v5 3/5] mm: introduce mmap3 for safely defining new mmap flags
From: Kirill A. Shutemov <hidden>
Date: 2017-08-16 11:15:41
Also in:
linux-fsdevel, linux-mm, linux-xfs, lkml, nvdimm
On Wed, Aug 16, 2017 at 12:44:22AM -0700, Dan Williams wrote:
quoted hunk ↗ jump to hunk
diff --git a/include/linux/mman.h b/include/linux/mman.h index c8367041fafd..0e1de42c836f 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h@@ -7,6 +7,40 @@ #include <linux/atomic.h> #include <uapi/linux/mman.h> +#ifndef MAP_32BIT +#define MAP_32BIT 0 +#endif +#ifndef MAP_HUGE_2MB +#define MAP_HUGE_2MB 0 +#endif +#ifndef MAP_HUGE_1GB +#define MAP_HUGE_1GB 0 +#endif + +/* + * The historical set of flags that all mmap implementations implicitly + * support when file_operations.mmap_supported_mask is zero. + */ +#define LEGACY_MAP_SUPPORTED_MASK (MAP_SHARED \ + | MAP_PRIVATE \ + | MAP_FIXED \ + | MAP_ANONYMOUS \ + | MAP_UNINITIALIZED \ + | MAP_GROWSDOWN \ + | MAP_DENYWRITE \ + | MAP_EXECUTABLE \ + | MAP_LOCKED \ + | MAP_NORESERVE \ + | MAP_POPULATE \ + | MAP_NONBLOCK \ + | MAP_STACK \ + | MAP_HUGETLB \ + | MAP_32BIT \ + | MAP_HUGE_2MB \ + | MAP_HUGE_1GB) + +#define MAP_SUPPORTED_MASK (LEGACY_MAP_SUPPORTED_MASK) + extern int sysctl_overcommit_memory; extern int sysctl_overcommit_ratio; extern unsigned long sysctl_overcommit_kbytes;
Since we looking into mmap(2) ABI, maybe we should consider re-defining MAP_DENYWRITE and MAP_EXECUTABLE as 0 in hope that we would be able to re-use these bits in the future? These flags are ignored now anyway. -- Kirill A. Shutemov