[PATCH v2 14/17] pmem: kill wmb_pmem()

All users have been replaced with flushing in the pmem driver. Cc: Ross Zwisler <ross.zwisler(a)linux.intel.com&gt; Signed-off-by: Dan Williams <dan.j.williams(a)intel.com&gt; --- arch/x86/include/asm/pmem.h | 36 ++------------------------------- include/linux/pmem.h | 47 ++++--------------------------------------- 2 files changed, 6 insertions(+), 77 deletions(-) diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h index fbc5e92e1ecc..a8cf2a6b14d9 100644 --- a/arch/x86/include/asm/pmem.h +++ b/arch/x86/include/asm/pmem.h @@ -26,8 +26,7 @@ * @n: length of the copy in bytes * * Copy data to persistent memory media via non-temporal stores so that - * a subsequent arch_wmb_pmem() can flush cpu and memory controller - * write buffers to guarantee durability. + * a subsequent pmem driver flush operation will drain posted write queues. */ static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src, size_t n) @@ -57,32 +56,12 @@ static inline int arch_memcpy_from_pmem(void *dst, const void __pmem *src, } /** - * arch_wmb_pmem - synchronize writes to persistent memory - * - * After a series of arch_memcpy_to_pmem() operations this drains data - * from cpu write buffers and any platform (memory controller) buffers - * to ensure that written data is durable on persistent memory media. - */ -static inline void arch_wmb_pmem(void) -{ - /* - * wmb() to 'sfence' all previous writes such that they are - * architecturally visible to 'pcommit'. Note, that we've - * already arranged for pmem writes to avoid the cache via - * arch_memcpy_to_pmem(). - */ - wmb(); - pcommit_sfence(); -} - -/** * arch_wb_cache_pmem - write back a cache range with CLWB * @vaddr: virtual start address * @size: number of bytes to write back * * Write back a cache range using the CLWB (cache line write back) - * instruction. This function requires explicit ordering with an - * arch_wmb_pmem() call. + * instruction. */ static inline void arch_wb_cache_pmem(void __pmem *addr, size_t size) { @@ -113,7 +92,6 @@ static inline bool __iter_needs_pmem_wb(struct iov_iter *i) * @i: iterator with source data * * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'. - * This function requires explicit ordering with an arch_wmb_pmem() call. */ static inline size_t arch_copy_from_iter_pmem(void __pmem *addr, size_t bytes, struct iov_iter *i) @@ -136,7 +114,6 @@ static inline size_t arch_copy_from_iter_pmem(void __pmem *addr, size_t bytes, * @size: number of bytes to zero * * Write zeros into the memory range starting at 'addr' for 'size' bytes. - * This function requires explicit ordering with an arch_wmb_pmem() call. */ static inline void arch_clear_pmem(void __pmem *addr, size_t size) { @@ -150,14 +127,5 @@ static inline void arch_invalidate_pmem(void __pmem *addr, size_t size) { clflush_cache_range((void __force *) addr, size); } - -static inline bool __arch_has_wmb_pmem(void) -{ - /* - * We require that wmb() be an 'sfence', that is only guaranteed on - * 64-bit builds - */ - return static_cpu_has(X86_FEATURE_PCOMMIT); -} #endif /* CONFIG_ARCH_HAS_PMEM_API */ #endif /* __ASM_X86_PMEM_H__ */ diff --git a/include/linux/pmem.h b/include/linux/pmem.h index 57d146fe44dd..9e3ea94b8157 100644 --- a/include/linux/pmem.h +++ b/include/linux/pmem.h @@ -26,16 +26,6 @@ * calling these symbols with arch_has_pmem_api() and redirect to the * implementation in asm/pmem.h. */ -static inline bool __arch_has_wmb_pmem(void) -{ - return false; -} - -static inline void arch_wmb_pmem(void) -{ - BUG(); -} - static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src, size_t n) { @@ -101,20 +91,6 @@ static inline int memcpy_from_pmem(void *dst, void __pmem const *src, return default_memcpy_from_pmem(dst, src, size); } -/** - * arch_has_wmb_pmem - true if wmb_pmem() ensures durability - * - * For a given cpu implementation within an architecture it is possible - * that wmb_pmem() resolves to a nop. In the case this returns - * false, pmem api users are unable to ensure durability and may want to - * fall back to a different data consistency model, or otherwise notify - * the user. - */ -static inline bool arch_has_wmb_pmem(void) -{ - return arch_has_pmem_api() && __arch_has_wmb_pmem(); -} - /* * These defaults seek to offer decent performance and minimize the * window between i/o completion and writes being durable on media. @@ -152,7 +128,7 @@ static inline void default_clear_pmem(void __pmem *addr, size_t size) * being effectively evicted from, or never written to, the processor * cache hierarchy after the copy completes. After memcpy_to_pmem() * data may still reside in cpu or platform buffers, so this operation - * must be followed by a wmb_pmem(). + * must be followed by a blkdev_issue_flush() on the pmem block device. */ static inline void memcpy_to_pmem(void __pmem *dst, const void *src, size_t n) { @@ -163,28 +139,13 @@ static inline void memcpy_to_pmem(void __pmem *dst, const void *src, size_t n) } /** - * wmb_pmem - synchronize writes to persistent memory - * - * After a series of memcpy_to_pmem() operations this drains data from - * cpu write buffers and any platform (memory controller) buffers to - * ensure that written data is durable on persistent memory media. - */ -static inline void wmb_pmem(void) -{ - if (arch_has_wmb_pmem()) - arch_wmb_pmem(); - else - wmb(); -} - -/** * copy_from_iter_pmem - copy data from an iterator to PMEM * @addr: PMEM destination address * @bytes: number of bytes to copy * @i: iterator with source data * * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'. - * This function requires explicit ordering with a wmb_pmem() call. + * See blkdev_issue_flush() note for memcpy_to_pmem(). */ static inline size_t copy_from_iter_pmem(void __pmem *addr, size_t bytes, struct iov_iter *i) @@ -200,7 +161,7 @@ static inline size_t copy_from_iter_pmem(void __pmem *addr, size_t bytes, * @size: number of bytes to zero * * Write zeros into the memory range starting at 'addr' for 'size' bytes. - * This function requires explicit ordering with a wmb_pmem() call. + * See blkdev_issue_flush() note for memcpy_to_pmem(). */ static inline void clear_pmem(void __pmem *addr, size_t size) { @@ -230,7 +191,7 @@ static inline void invalidate_pmem(void __pmem *addr, size_t size) * @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. + * See blkdev_issue_flush() note for memcpy_to_pmem(). */ static inline void wb_cache_pmem(void __pmem *addr, size_t size) {