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| author | Dan Williams <dan.j.williams@intel.com> | 2017-10-23 17:20:00 +0300 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2018-01-20 03:50:53 +0300 |
| commit | 785a3fab4adbf91b2189c928a59ae219c54ba95e (patch) | |
| tree | 7a3f3342c336eb99cbc7ddbe09741af78d7e99b2 /include/linux/pfn_t.h | |
| parent | 77dd66a3c67c93ab401ccc15efff25578be281fd (diff) | |
| download | linux-785a3fab4adbf91b2189c928a59ae219c54ba95e.tar.xz | |
mm, dax: introduce pfn_t_special()
In support of removing the VM_MIXEDMAP indication from DAX VMAs,
introduce pfn_t_special() for drivers to indicate that _PAGE_SPECIAL
should be used for DAX ptes. This also helps identify drivers like
dccssblk that only want to use DAX in a read-only fashion without
get_user_pages() support.
Ideally we could delete axonram and dcssblk DAX support, but if we need
to keep it better make it explicit that axonram and dcssblk only support
a sub-set of DAX due to missing _PAGE_DEVMAP support.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'include/linux/pfn_t.h')
| -rw-r--r-- | include/linux/pfn_t.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h index 43b1d7648e82..a03c2642a87c 100644 --- a/include/linux/pfn_t.h +++ b/include/linux/pfn_t.h @@ -15,8 +15,10 @@ #define PFN_SG_LAST (1ULL << (BITS_PER_LONG_LONG - 2)) #define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3)) #define PFN_MAP (1ULL << (BITS_PER_LONG_LONG - 4)) +#define PFN_SPECIAL (1ULL << (BITS_PER_LONG_LONG - 5)) #define PFN_FLAGS_TRACE \ + { PFN_SPECIAL, "SPECIAL" }, \ { PFN_SG_CHAIN, "SG_CHAIN" }, \ { PFN_SG_LAST, "SG_LAST" }, \ { PFN_DEV, "DEV" }, \ @@ -120,4 +122,15 @@ pud_t pud_mkdevmap(pud_t pud); #endif #endif /* __HAVE_ARCH_PTE_DEVMAP */ +#ifdef __HAVE_ARCH_PTE_SPECIAL +static inline bool pfn_t_special(pfn_t pfn) +{ + return (pfn.val & PFN_SPECIAL) == PFN_SPECIAL; +} +#else +static inline bool pfn_t_special(pfn_t pfn) +{ + return false; +} +#endif /* __HAVE_ARCH_PTE_SPECIAL */ #endif /* _LINUX_PFN_T_H_ */ |