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pmem: add wb_cache_pmem() to the PMEM API

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__arch_wb_cache_pmem() was already an internal implementation detail of
the x86 PMEM API, but this functionality needs to be exported as part of
the general PMEM API to handle the fsync/msync case for DAX mmaps.

One thing worth noting is that we really do want this to be part of the
PMEM API as opposed to a stand-alone function like clflush_cache_range()
because of ordering restrictions.  By having wb_cache_pmem() as part of
the PMEM API we can leave it unordered, call it multiple times to write
back large amounts of memory, and then order the multiple calls with a
single wmb_pmem().

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.com>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ross Zwisler
2016-01-22 15:10:37 -08:00
committed by Linus Torvalds
parent de14b9cb5e
commit 3f4a2670de
2 changed files with 27 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
include/linux/pmem.h
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@@ -53,12 +53,18 @@ static inline void arch_clear_pmem(void __pmem *addr, size_t size)
{
BUG();
}
static inline void arch_wb_cache_pmem(void __pmem *addr, size_t size)
{
BUG();
}
#endif
/*
* Architectures that define ARCH_HAS_PMEM_API must provide
* implementations for arch_memcpy_to_pmem(), arch_wmb_pmem(),
* arch_copy_from_iter_pmem(), arch_clear_pmem() and arch_has_wmb_pmem().
* arch_copy_from_iter_pmem(), arch_clear_pmem(), arch_wb_cache_pmem()
* and arch_has_wmb_pmem().
*/
static inline void memcpy_from_pmem(void *dst, void __pmem const *src, size_t size)
{
@@ -178,4 +184,18 @@ static inline void clear_pmem(void __pmem *addr, size_t size)
else
default_clear_pmem(addr, size);
}
/**
* wb_cache_pmem - write back processor cache for PMEM memory range
* @addr: virtual start address
* @size: number of bytes to write back
*
* Write back the processor cache range starting at 'addr' for 'size' bytes.
* This function requires explicit ordering with a wmb_pmem() call.
*/
static inline void wb_cache_pmem(void __pmem *addr, size_t size)
{
if (arch_has_pmem_api())
arch_wb_cache_pmem(addr, size);
}
#endif /* __PMEM_H__ */