flush_kernel_dcache_page fixes and removal

exactly the same thing, can contains one or more of the following:

 1) an optimization to defer the cache flush for page cache pages not
    mapped into userspace
 2) additional flushing for mapped page cache pages if cache aliases
    are possible

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/core-api/cachetlb.rst           | 86 ++++++++-----------
 .../translations/zh_CN/core-api/cachetlb.rst  |  9 --
 arch/arm/include/asm/cacheflush.h             |  4 +-
 arch/arm/mm/flush.c                           | 33 -------
 arch/arm/mm/nommu.c                           |  6 --
 arch/csky/abiv1/cacheflush.c                  | 11 ---
 arch/csky/abiv1/inc/abi/cacheflush.h          |  4 +-
 arch/mips/include/asm/cacheflush.h            |  8 +-
 arch/nds32/include/asm/cacheflush.h           |  3 +-
 arch/nds32/mm/cacheflush.c                    |  9 --
 arch/parisc/include/asm/cacheflush.h          |  8 +-
 arch/parisc/kernel/cache.c                    |  3 +-
 arch/sh/include/asm/cacheflush.h              |  8 +-
 block/blk-map.c                               |  2 +-
 fs/exec.c                                     |  6 +-
 include/linux/highmem.h                       |  5 +-
 tools/testing/scatterlist/linux/mm.h          |  1 -
 17 files changed, 51 insertions(+), 155 deletions(-)

diff --git a/Documentation/core-api/cachetlb.rst b/Documentation/core-api/cachetlb.rst
index fe4290e26729..8aed9103e48a 100644
--- a/Documentation/core-api/cachetlb.rst
+++ b/Documentation/core-api/cachetlb.rst

@@ -271,10 +271,15 @@ maps this page at its virtual address.
 
   ``void flush_dcache_page(struct page *page)``
 
-	Any time the kernel writes to a page cache page, _OR_
-	the kernel is about to read from a page cache page and
-	user space shared/writable mappings of this page potentially
-	exist, this routine is called.
+        This routines must be called when:
+
+	  a) the kernel did write to a page that is in the page cache page
+	     and / or in high memory
+	  b) the kernel is about to read from a page cache page and user space
+	     shared/writable mappings of this page potentially exist.  Note
+	     that {get,pin}_user_pages{_fast} already call flush_dcache_page
+	     on any page found in the user address space and thus driver
+	     code rarely needs to take this into account.
 
 	.. note::
 

@@ -284,38 +289,34 @@ maps this page at its virtual address.
 	      handling vfs symlinks in the page cache need not call
 	      this interface at all.
 
-	The phrase "kernel writes to a page cache page" means,
-	specifically, that the kernel executes store instructions
-	that dirty data in that page at the page->virtual mapping
-	of that page.  It is important to flush here to handle
-	D-cache aliasing, to make sure these kernel stores are
-	visible to user space mappings of that page.
-
-	The corollary case is just as important, if there are users
-	which have shared+writable mappings of this file, we must make
-	sure that kernel reads of these pages will see the most recent
-	stores done by the user.
-
-	If D-cache aliasing is not an issue, this routine may
-	simply be defined as a nop on that architecture.
-
-        There is a bit set aside in page->flags (PG_arch_1) as
-	"architecture private".  The kernel guarantees that,
-	for pagecache pages, it will clear this bit when such
-	a page first enters the pagecache.
-
-	This allows these interfaces to be implemented much more
-	efficiently.  It allows one to "defer" (perhaps indefinitely)
-	the actual flush if there are currently no user processes
-	mapping this page.  See sparc64's flush_dcache_page and
-	update_mmu_cache implementations for an example of how to go
-	about doing this.
-
-	The idea is, first at flush_dcache_page() time, if
-	page->mapping->i_mmap is an empty tree, just mark the architecture
-	private page flag bit.  Later, in update_mmu_cache(), a check is
-	made of this flag bit, and if set the flush is done and the flag
-	bit is cleared.
+	The phrase "kernel writes to a page cache page" means, specifically,
+	that the kernel executes store instructions that dirty data in that
+	page at the page->virtual mapping of that page.  It is important to
+	flush here to handle D-cache aliasing, to make sure these kernel stores
+	are visible to user space mappings of that page.
+
+	The corollary case is just as important, if there are users which have
+	shared+writable mappings of this file, we must make sure that kernel
+	reads of these pages will see the most recent stores done by the user.
+
+	If D-cache aliasing is not an issue, this routine may simply be defined
+	as a nop on that architecture.
+
+        There is a bit set aside in page->flags (PG_arch_1) as "architecture
+	private".  The kernel guarantees that, for pagecache pages, it will
+	clear this bit when such a page first enters the pagecache.
+
+	This allows these interfaces to be implemented much more efficiently.
+	It allows one to "defer" (perhaps indefinitely) the actual flush if
+	there are currently no user processes mapping this page.  See sparc64's
+	flush_dcache_page and update_mmu_cache implementations for an example
+	of how to go about doing this.
+
+	The idea is, first at flush_dcache_page() time, if page_file_mapping()
+	returns a mapping, and mapping_mapped on that mapping returns %false,
+	just mark the architecture private page flag bit.  Later, in
+	update_mmu_cache(), a check is made of this flag bit, and if set the
+	flush is done and the flag bit is cleared.
 
 	.. important::
 

@@ -351,19 +352,6 @@ maps this page at its virtual address.
 	architectures).  For incoherent architectures, it should flush
 	the cache of the page at vmaddr.
 
-  ``void flush_kernel_dcache_page(struct page *page)``
-
-	When the kernel needs to modify a user page is has obtained
-	with kmap, it calls this function after all modifications are
-	complete (but before kunmapping it) to bring the underlying
-	page up to date.  It is assumed here that the user has no
-	incoherent cached copies (i.e. the original page was obtained
-	from a mechanism like get_user_pages()).  The default
-	implementation is a nop and should remain so on all coherent
-	architectures.  On incoherent architectures, this should flush
-	the kernel cache for page (using page_address(page)).
-
-
   ``void flush_icache_range(unsigned long start, unsigned long end)``
 
   	When the kernel stores into addresses that it will execute

diff --git a/Documentation/translations/zh_CN/core-api/cachetlb.rst b/Documentation/translations/zh_CN/core-api/cachetlb.rst
index 8376485a534d..55827b8a7c53 100644
--- a/Documentation/translations/zh_CN/core-api/cachetlb.rst
+++ b/Documentation/translations/zh_CN/core-api/cachetlb.rst

@@ -298,15 +298,6 @@ HyperSparc cpu就是这样一个具有这种属性的cpu。
 	用。默认的实现是nop（对于所有相干的架构应该保持这样）。对于不一致性
 	的架构，它应该刷新vmaddr处的页面缓存。
 
-  ``void flush_kernel_dcache_page(struct page *page)``
-
-	当内核需要修改一个用kmap获得的用户页时，它会在所有修改完成后（但在
-	kunmapping之前）调用这个函数，以使底层页面达到最新状态。这里假定用
-	户没有不一致性的缓存副本（即原始页面是从类似get_user_pages()的机制
-	中获得的）。默认的实现是一个nop，在所有相干的架构上都应该如此。在不
-	一致性的架构上，这应该刷新内核缓存中的页面（使用page_address(page)）。
-
-
   ``void flush_icache_range(unsigned long start, unsigned long end)``
 
 	当内核存储到它将执行的地址中时（例如在加载模块时），这个函数被调用。

diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index 2e24e765e6d3..5e56288e343b 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h

@@ -291,6 +291,7 @@ extern void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *);
 
+#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 static inline void flush_kernel_vmap_range(void *addr, int size)
 {
 	if ((cache_is_vivt() || cache_is_vipt_aliasing()))

@@ -312,9 +313,6 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 		__flush_anon_page(vma, page, vmaddr);
 }
 
-#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-extern void flush_kernel_dcache_page(struct page *);
-
 #define flush_dcache_mmap_lock(mapping)		xa_lock_irq(&mapping->i_pages)
 #define flush_dcache_mmap_unlock(mapping)	xa_unlock_irq(&mapping->i_pages)
 

diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 6d89db7895d1..7ff9feea13a6 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c

@@ -345,39 +345,6 @@ void flush_dcache_page(struct page *page)
 }
 EXPORT_SYMBOL(flush_dcache_page);
 
-/*
- * Ensure cache coherency for the kernel mapping of this page. We can
- * assume that the page is pinned via kmap.
- *
- * If the page only exists in the page cache and there are no user
- * space mappings, this is a no-op since the page was already marked
- * dirty at creation.  Otherwise, we need to flush the dirty kernel
- * cache lines directly.
- */
-void flush_kernel_dcache_page(struct page *page)
-{
-	if (cache_is_vivt() || cache_is_vipt_aliasing()) {
-		struct address_space *mapping;
-
-		mapping = page_mapping_file(page);
-
-		if (!mapping || mapping_mapped(mapping)) {
-			void *addr;
-
-			addr = page_address(page);
-			/*
-			 * kmap_atomic() doesn't set the page virtual
-			 * address for highmem pages, and
-			 * kunmap_atomic() takes care of cache
-			 * flushing already.
-			 */
-			if (!IS_ENABLED(CONFIG_HIGHMEM) || addr)
-				__cpuc_flush_dcache_area(addr, PAGE_SIZE);
-		}
-	}
-}
-EXPORT_SYMBOL(flush_kernel_dcache_page);
-
 /*
  * Flush an anonymous page so that users of get_user_pages()
  * can safely access the data.  The expected sequence is:

diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index 8b3d7191e2b8..2658f52903da 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c

@@ -166,12 +166,6 @@ void flush_dcache_page(struct page *page)
 }
 EXPORT_SYMBOL(flush_dcache_page);
 
-void flush_kernel_dcache_page(struct page *page)
-{
-	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
-}
-EXPORT_SYMBOL(flush_kernel_dcache_page);
-
 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 		       unsigned long uaddr, void *dst, const void *src,
 		       unsigned long len)

diff --git a/arch/csky/abiv1/cacheflush.c b/arch/csky/abiv1/cacheflush.c
index 07ff17ea33de..fb91b069dc69 100644
--- a/arch/csky/abiv1/cacheflush.c
+++ b/arch/csky/abiv1/cacheflush.c

@@ -56,17 +56,6 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
 	}
 }
 
-void flush_kernel_dcache_page(struct page *page)
-{
-	struct address_space *mapping;
-
-	mapping = page_mapping_file(page);
-
-	if (!mapping || mapping_mapped(mapping))
-		dcache_wbinv_all();
-}
-EXPORT_SYMBOL(flush_kernel_dcache_page);
-
 void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
 	unsigned long end)
 {

diff --git a/arch/csky/abiv1/inc/abi/cacheflush.h b/arch/csky/abiv1/inc/abi/cacheflush.h
index 6cab7afae962..ed62e2066ba7 100644
--- a/arch/csky/abiv1/inc/abi/cacheflush.h
+++ b/arch/csky/abiv1/inc/abi/cacheflush.h

@@ -14,12 +14,10 @@ extern void flush_dcache_page(struct page *);
 #define flush_cache_page(vma, page, pfn)	cache_wbinv_all()
 #define flush_cache_dup_mm(mm)			cache_wbinv_all()
 
-#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-extern void flush_kernel_dcache_page(struct page *);
-
 #define flush_dcache_mmap_lock(mapping)		xa_lock_irq(&mapping->i_pages)
 #define flush_dcache_mmap_unlock(mapping)	xa_unlock_irq(&mapping->i_pages)
 
+#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 static inline void flush_kernel_vmap_range(void *addr, int size)
 {
 	dcache_wbinv_all();

diff --git a/arch/mips/include/asm/cacheflush.h b/arch/mips/include/asm/cacheflush.h
index d687b40b9fbb..b3dc9c589442 100644
--- a/arch/mips/include/asm/cacheflush.h
+++ b/arch/mips/include/asm/cacheflush.h

@@ -125,13 +125,7 @@ static inline void kunmap_noncoherent(void)
 	kunmap_coherent();
 }
 
-#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-static inline void flush_kernel_dcache_page(struct page *page)
-{
-	BUG_ON(cpu_has_dc_aliases && PageHighMem(page));
-	flush_dcache_page(page);
-}
-
+#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 /*
  * For now flush_kernel_vmap_range and invalidate_kernel_vmap_range both do a
  * cache writeback and invalidate operation.

diff --git a/arch/nds32/include/asm/cacheflush.h b/arch/nds32/include/asm/cacheflush.h
index 7d6824f7c0e8..c2a222ebfa2a 100644
--- a/arch/nds32/include/asm/cacheflush.h
+++ b/arch/nds32/include/asm/cacheflush.h

@@ -36,8 +36,7 @@ void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
 void flush_anon_page(struct vm_area_struct *vma,
 		     struct page *page, unsigned long vaddr);
 
-#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-void flush_kernel_dcache_page(struct page *page);
+#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 void flush_kernel_vmap_range(void *addr, int size);
 void invalidate_kernel_vmap_range(void *addr, int size);
 #define flush_dcache_mmap_lock(mapping)   xa_lock_irq(&(mapping)->i_pages)

diff --git a/arch/nds32/mm/cacheflush.c b/arch/nds32/mm/cacheflush.c
index ad5344ef5d33..07aac65d1cab 100644
--- a/arch/nds32/mm/cacheflush.c
+++ b/arch/nds32/mm/cacheflush.c

@@ -318,15 +318,6 @@ void flush_anon_page(struct vm_area_struct *vma,
 	local_irq_restore(flags);
 }
 
-void flush_kernel_dcache_page(struct page *page)
-{
-	unsigned long flags;
-	local_irq_save(flags);
-	cpu_dcache_wbinval_page((unsigned long)page_address(page));
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL(flush_kernel_dcache_page);
-
 void flush_kernel_vmap_range(void *addr, int size)
 {
 	unsigned long flags;

diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h
index 99663fc1f997..eef0096db5f8 100644
--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h

@@ -36,16 +36,12 @@ void flush_cache_all_local(void);
 void flush_cache_all(void);
 void flush_cache_mm(struct mm_struct *mm);
 
-#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
 void flush_kernel_dcache_page_addr(void *addr);
-static inline void flush_kernel_dcache_page(struct page *page)
-{
-	flush_kernel_dcache_page_addr(page_address(page));
-}
 
 #define flush_kernel_dcache_range(start,size) \
 	flush_kernel_dcache_range_asm((start), (start)+(size));
 
+#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 void flush_kernel_vmap_range(void *vaddr, int size);
 void invalidate_kernel_vmap_range(void *vaddr, int size);
 

@@ -59,7 +55,7 @@ extern void flush_dcache_page(struct page *page);
 #define flush_dcache_mmap_unlock(mapping)	xa_unlock_irq(&mapping->i_pages)
 
 #define flush_icache_page(vma,page)	do { 		\
-	flush_kernel_dcache_page(page);			\
+	flush_kernel_dcache_page_addr(page_address(page)); \
 	flush_kernel_icache_page(page_address(page)); 	\
 } while (0)
 

diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 86a1a63563fd..39e02227e231 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c

@@ -334,7 +334,7 @@ void flush_dcache_page(struct page *page)
 		return;
 	}
 
-	flush_kernel_dcache_page(page);
+	flush_kernel_dcache_page_addr(page_address(page));
 
 	if (!mapping)
 		return;

@@ -375,7 +375,6 @@ EXPORT_SYMBOL(flush_dcache_page);
 
 /* Defined in arch/parisc/kernel/pacache.S */
 EXPORT_SYMBOL(flush_kernel_dcache_range_asm);
-EXPORT_SYMBOL(flush_kernel_dcache_page_asm);
 EXPORT_SYMBOL(flush_data_cache_local);
 EXPORT_SYMBOL(flush_kernel_icache_range_asm);
 

diff --git a/arch/sh/include/asm/cacheflush.h b/arch/sh/include/asm/cacheflush.h
index 4486a865ff62..372afa82fee6 100644
--- a/arch/sh/include/asm/cacheflush.h
+++ b/arch/sh/include/asm/cacheflush.h

@@ -63,6 +63,8 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 	if (boot_cpu_data.dcache.n_aliases && PageAnon(page))
 		__flush_anon_page(page, vmaddr);
 }
+
+#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 static inline void flush_kernel_vmap_range(void *addr, int size)
 {
 	__flush_wback_region(addr, size);

@@ -72,12 +74,6 @@ static inline void invalidate_kernel_vmap_range(void *addr, int size)
 	__flush_invalidate_region(addr, size);
 }
 
-#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-static inline void flush_kernel_dcache_page(struct page *page)
-{
-	flush_dcache_page(page);
-}
-
 extern void copy_to_user_page(struct vm_area_struct *vma,
 	struct page *page, unsigned long vaddr, void *dst, const void *src,
 	unsigned long len);

diff --git a/block/blk-map.c b/block/blk-map.c
index 3743158ddaeb..4639bc6b5c62 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c

@@ -309,7 +309,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
 
 static void bio_invalidate_vmalloc_pages(struct bio *bio)
 {
-#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
+#ifdef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
 	if (bio->bi_private && !op_is_write(bio_op(bio))) {
 		unsigned long i, len = 0;
 

diff --git a/fs/exec.c b/fs/exec.c
index 38f63451b928..41a888d4edde 100644
--- a/fs/exec.c
+++ b/fs/exec.c

@@ -574,7 +574,7 @@ static int copy_strings(int argc, struct user_arg_ptr argv,
 				}
 
 				if (kmapped_page) {
-					flush_kernel_dcache_page(kmapped_page);
+					flush_dcache_page(kmapped_page);
 					kunmap(kmapped_page);
 					put_arg_page(kmapped_page);
 				}

@@ -592,7 +592,7 @@ static int copy_strings(int argc, struct user_arg_ptr argv,
 	ret = 0;
 out:
 	if (kmapped_page) {
-		flush_kernel_dcache_page(kmapped_page);
+		flush_dcache_page(kmapped_page);
 		kunmap(kmapped_page);
 		put_arg_page(kmapped_page);
 	}

@@ -634,7 +634,7 @@ int copy_string_kernel(const char *arg, struct linux_binprm *bprm)
 		kaddr = kmap_atomic(page);
 		flush_arg_page(bprm, pos & PAGE_MASK, page);
 		memcpy(kaddr + offset_in_page(pos), arg, bytes_to_copy);
-		flush_kernel_dcache_page(page);
+		flush_dcache_page(page);
 		kunmap_atomic(kaddr);
 		put_arg_page(page);
 	}

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 8c6e8e996c87..e95551bf99e9 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h

@@ -130,10 +130,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page
 }
 #endif
 
-#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-static inline void flush_kernel_dcache_page(struct page *page)
-{
-}
+#ifndef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
 static inline void flush_kernel_vmap_range(void *vaddr, int size)
 {
 }

diff --git a/tools/testing/scatterlist/linux/mm.h b/tools/testing/scatterlist/linux/mm.h
index f9a12005fcea..16ec895bbe5f 100644
--- a/tools/testing/scatterlist/linux/mm.h
+++ b/tools/testing/scatterlist/linux/mm.h

@@ -127,7 +127,6 @@ kmalloc_array(unsigned int n, unsigned int size, unsigned int flags)
 #define kmemleak_free(a)
 
 #define PageSlab(p) (0)
-#define flush_kernel_dcache_page(p)
 
 #define MAX_ERRNO	4095
 

-- 
2.30.2

+++ b/drivers/block/ps3disk.c
 		offset += size;
-		flush_kernel_dcache_page(bvec.bv_page);
+		flush_dcache_page(bvec.bv_page);
 		bvec_kunmap_irq(buf, &flags);

---
 drivers/mmc/host/jz4740_mmc.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/mmc/host/jz4740_mmc.c 

b/drivers/mmc/host/jz4740_mmc.c
index 0db17bcc9c16..aa2240c83510 100644

--- a/drivers/mmc/host/jz4740_mmc.c
+++ b/drivers/mmc/host/jz4740_mmc.c

@@ -578,10 +578,6 @@ static bool jz4740_mmc_read_data(struct 

jz4740_mmc_host *host,
 			}
 		}
 		data->bytes_xfered += miter->length;
-
-		/* This can go away once MIPS implements
-		 * flush_kernel_dcache_page */
-		flush_dcache_page(miter->page);
 	}
 	sg_miter_stop(miter);

--
2.30.2

---
 drivers/mmc/host/jz4740_mmc.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/mmc/host/jz4740_mmc.c b/drivers/mmc/host/jz4740_mmc.c
index 0db17bcc9c16..aa2240c83510 100644
--- a/drivers/mmc/host/jz4740_mmc.c
+++ b/drivers/mmc/host/jz4740_mmc.c

@@ -578,10 +578,6 @@ static bool jz4740_mmc_read_data(struct jz4740_mmc_host *host,
                        }
                }
                data->bytes_xfered += miter->length;
-
-               /* This can go away once MIPS implements
-                * flush_kernel_dcache_page */
-               flush_dcache_page(miter->page);
        }
        sg_miter_stop(miter);

--

2.30.2

---
 drivers/mmc/host/mmc_spi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 65c65bb5737f..3d28a3d3001b 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c

@@ -948,7 +948,7 @@ mmc_spi_data_do(struct mmc_spi_host *host, struct mmc_command *cmd,

                /* discard mappings */
                if (direction == DMA_FROM_DEVICE)
-                       flush_kernel_dcache_page(sg_page(sg));
+                       flush_dcache_page(sg_page(sg));
                kunmap(sg_page(sg));
                if (dma_dev)
                        dma_unmap_page(dma_dev, dma_addr, PAGE_SIZE, dir);
--

2.30.2