block: add helpers to run flush_dcache_page() against a bio and a request's pages

Mtdblock driver doesn't call flush_dcache_page for pages in request.  So,
this causes problems on architectures where the icache doesn't fill from
the dcache or with dcache aliases.  The patch fixes this.

The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid
pointless empty cache-thrashing loops on architectures for which
flush_dcache_page() is a no-op.  Every architecture was provided with this
flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is
equal 1 or do nothing otherwise.

See "fix mtd_blkdevs problem with caches on some architectures" discussion
on LKML for more information.

Signed-off-by: Ilya Loginov <isloginov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Peter Horton <phorton@bitbox.co.uk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/arch/alpha/include/asm/cacheflush.h b/arch/alpha/include/asm/cacheflush.h
index b686cc7..01d71e1 100644 (file)
--- a/arch/alpha/include/asm/cacheflush.h
+++ b/arch/alpha/include/asm/cacheflush.h
@@ -9,6 +9,7 @@
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index fd03fb6..247b7b0 100644 (file)
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -408,6 +408,7 @@ extern void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
  * about to change to user space.  This is the same method as used on SPARC64.
  * See update_mmu_cache for the user space part.
  */
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *);
 
 extern void __flush_dcache_page(struct address_space *mapping, struct page *page);

diff --git a/arch/avr32/include/asm/cacheflush.h b/arch/avr32/include/asm/cacheflush.h
index 6706747..96e5382 100644 (file)
--- a/arch/avr32/include/asm/cacheflush.h
+++ b/arch/avr32/include/asm/cacheflush.h
@@ -107,6 +107,7 @@ extern void flush_icache_page(struct vm_area_struct *vma, struct page *page);
  * do something here, but only for certain configurations.  No such
  * configurations exist at this time.
  */
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(page)           do { } while (0)
 #define flush_dcache_mmap_unlock(page)         do { } while (0)

diff --git a/arch/blackfin/include/asm/cacheflush.h b/arch/blackfin/include/asm/cacheflush.h
index af03a36..417eaac 100644 (file)
--- a/arch/blackfin/include/asm/cacheflush.h
+++ b/arch/blackfin/include/asm/cacheflush.h
@@ -68,9 +68,11 @@ do { memcpy(dst, src, len);                                          \
 #endif
 #if defined(CONFIG_BFIN_EXTMEM_WRITEBACK) || defined(CONFIG_BFIN_L2_WRITEBACK)
 # define flush_dcache_range(start,end)         blackfin_dcache_flush_range((start), (end))
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 # define flush_dcache_page(page)               blackfin_dflush_page(page_address(page))
 #else
 # define flush_dcache_range(start,end)         do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 # define flush_dcache_page(page)               do { } while (0)
 #endif
 

diff --git a/arch/cris/include/asm/cacheflush.h b/arch/cris/include/asm/cacheflush.h
index cf60e3f..36795bc 100644 (file)
--- a/arch/cris/include/asm/cacheflush.h
+++ b/arch/cris/include/asm/cacheflush.h
@@ -12,6 +12,7 @@
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/frv/include/asm/cacheflush.h b/arch/frv/include/asm/cacheflush.h
index 432a69e..edbac54 100644 (file)
--- a/arch/frv/include/asm/cacheflush.h
+++ b/arch/frv/include/asm/cacheflush.h
@@ -47,6 +47,7 @@ static inline void __flush_cache_all(void)
 }
 
 /* dcache/icache coherency... */
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #ifdef CONFIG_MMU
 extern void flush_dcache_page(struct page *page);
 #else

diff --git a/arch/h8300/include/asm/cacheflush.h b/arch/h8300/include/asm/cacheflush.h
index 5ffdca2..4cf2df2 100644 (file)
--- a/arch/h8300/include/asm/cacheflush.h
+++ b/arch/h8300/include/asm/cacheflush.h
@@ -15,6 +15,7 @@
 #define        flush_cache_dup_mm(mm)          do { } while (0)
 #define        flush_cache_range(vma,a,b)
 #define        flush_cache_page(vma,p,pfn)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define        flush_dcache_page(page)
 #define        flush_dcache_mmap_lock(mapping)
 #define        flush_dcache_mmap_unlock(mapping)

diff --git a/arch/ia64/include/asm/cacheflush.h b/arch/ia64/include/asm/cacheflush.h
index c8ce271..429eefc 100644 (file)
--- a/arch/ia64/include/asm/cacheflush.h
+++ b/arch/ia64/include/asm/cacheflush.h
@@ -25,6 +25,7 @@
 #define flush_cache_vmap(start, end)           do { } while (0)
 #define flush_cache_vunmap(start, end)         do { } while (0)
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #define flush_dcache_page(page)                        \
 do {                                           \
        clear_bit(PG_arch_1, &(page)->flags);   \

diff --git a/arch/m32r/include/asm/cacheflush.h b/arch/m32r/include/asm/cacheflush.h
index 78587c9..8e8e045 100644 (file)
--- a/arch/m32r/include/asm/cacheflush.h
+++ b/arch/m32r/include/asm/cacheflush.h
@@ -12,6 +12,7 @@ extern void _flush_cache_copyback_all(void);
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)
@@ -33,6 +34,7 @@ extern void smp_flush_cache_all(void);
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)
@@ -46,6 +48,7 @@ extern void smp_flush_cache_all(void);
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/m68k/include/asm/cacheflush_mm.h b/arch/m68k/include/asm/cacheflush_mm.h
index 16bf375..73de7c8 100644 (file)
--- a/arch/m68k/include/asm/cacheflush_mm.h
+++ b/arch/m68k/include/asm/cacheflush_mm.h
@@ -128,6 +128,7 @@ static inline void __flush_page_to_ram(void *vaddr)
        }
 }
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #define flush_dcache_page(page)                __flush_page_to_ram(page_address(page))
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/m68k/include/asm/cacheflush_no.h b/arch/m68k/include/asm/cacheflush_no.h
index c65f00a..89f1956 100644 (file)
--- a/arch/m68k/include/asm/cacheflush_no.h
+++ b/arch/m68k/include/asm/cacheflush_no.h
@@ -12,6 +12,7 @@
 #define flush_cache_range(vma, start, end)     __flush_cache_all()
 #define flush_cache_page(vma, vmaddr)          do { } while (0)
 #define flush_dcache_range(start,len)          __flush_cache_all()
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/microblaze/include/asm/cacheflush.h b/arch/microblaze/include/asm/cacheflush.h
index f989d6a..088076e 100644 (file)
--- a/arch/microblaze/include/asm/cacheflush.h
+++ b/arch/microblaze/include/asm/cacheflush.h
@@ -37,6 +37,7 @@
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
 
 #define flush_dcache_range(start, end) __invalidate_dcache_range(start, end)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/mips/include/asm/cacheflush.h b/arch/mips/include/asm/cacheflush.h
index 03b1d69..40bb9fd 100644 (file)
--- a/arch/mips/include/asm/cacheflush.h
+++ b/arch/mips/include/asm/cacheflush.h
@@ -38,6 +38,7 @@ extern void (*flush_cache_range)(struct vm_area_struct *vma,
 extern void (*flush_cache_page)(struct vm_area_struct *vma, unsigned long page, unsigned long pfn);
 extern void __flush_dcache_page(struct page *page);
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 static inline void flush_dcache_page(struct page *page)
 {
        if (cpu_has_dc_aliases || !cpu_has_ic_fills_f_dc)

diff --git a/arch/mn10300/include/asm/cacheflush.h b/arch/mn10300/include/asm/cacheflush.h
index 1a55d61..29e692f 100644 (file)
--- a/arch/mn10300/include/asm/cacheflush.h
+++ b/arch/mn10300/include/asm/cacheflush.h
@@ -26,6 +26,7 @@
 #define flush_cache_page(vma, vmaddr, pfn)     do {} while (0)
 #define flush_cache_vmap(start, end)           do {} while (0)
 #define flush_cache_vunmap(start, end)         do {} while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do {} while (0)
 #define flush_dcache_mmap_lock(mapping)                do {} while (0)
 #define flush_dcache_mmap_unlock(mapping)      do {} while (0)

diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h
index 7243951..7a73b61 100644 (file)
--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h
@@ -42,6 +42,7 @@ void flush_cache_mm(struct mm_struct *mm);
 #define flush_cache_vmap(start, end)           flush_cache_all()
 #define flush_cache_vunmap(start, end)         flush_cache_all()
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *page);
 
 #define flush_dcache_mmap_lock(mapping) \

diff --git a/arch/powerpc/include/asm/cacheflush.h b/arch/powerpc/include/asm/cacheflush.h
index ba667a3..ab9e402 100644 (file)
--- a/arch/powerpc/include/asm/cacheflush.h
+++ b/arch/powerpc/include/asm/cacheflush.h
@@ -25,6 +25,7 @@
 #define flush_cache_vmap(start, end)           do { } while (0)
 #define flush_cache_vunmap(start, end)         do { } while (0)
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *page);
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/s390/include/asm/cacheflush.h b/arch/s390/include/asm/cacheflush.h
index 49d5af9..405cc97 100644 (file)
--- a/arch/s390/include/asm/cacheflush.h
+++ b/arch/s390/include/asm/cacheflush.h
@@ -10,6 +10,7 @@
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/score/include/asm/cacheflush.h b/arch/score/include/asm/cacheflush.h
index 07cc8fc..caaba24 100644 (file)
--- a/arch/score/include/asm/cacheflush.h
+++ b/arch/score/include/asm/cacheflush.h
@@ -16,6 +16,7 @@ extern void flush_icache_range(unsigned long start, unsigned long end);
 extern void flush_dcache_range(unsigned long start, unsigned long end);
 
 #define flush_cache_dup_mm(mm)                 do {} while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do {} while (0)
 #define flush_dcache_mmap_lock(mapping)                do {} while (0)
 #define flush_dcache_mmap_unlock(mapping)      do {} while (0)

diff --git a/arch/sh/include/asm/cacheflush.h b/arch/sh/include/asm/cacheflush.h
index c29918f..dda96eb 100644 (file)
--- a/arch/sh/include/asm/cacheflush.h
+++ b/arch/sh/include/asm/cacheflush.h
@@ -42,6 +42,7 @@ extern void flush_cache_page(struct vm_area_struct *vma,
                                unsigned long addr, unsigned long pfn);
 extern void flush_cache_range(struct vm_area_struct *vma,
                                 unsigned long start, unsigned long end);
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *page);
 extern void flush_icache_range(unsigned long start, unsigned long end);
 extern void flush_icache_page(struct vm_area_struct *vma,

diff --git a/arch/sparc/include/asm/cacheflush_32.h b/arch/sparc/include/asm/cacheflush_32.h
index 68ac109..2e46877 100644 (file)
--- a/arch/sparc/include/asm/cacheflush_32.h
+++ b/arch/sparc/include/asm/cacheflush_32.h
@@ -75,6 +75,7 @@ BTFIXUPDEF_CALL(void, flush_sig_insns, struct mm_struct *, unsigned long)
 
 extern void sparc_flush_page_to_ram(struct page *page);
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #define flush_dcache_page(page)                        sparc_flush_page_to_ram(page)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/arch/sparc/include/asm/cacheflush_64.h b/arch/sparc/include/asm/cacheflush_64.h
index c433217..b953840 100644 (file)
--- a/arch/sparc/include/asm/cacheflush_64.h
+++ b/arch/sparc/include/asm/cacheflush_64.h
@@ -37,6 +37,7 @@ extern void flush_dcache_page_all(struct mm_struct *mm, struct page *page);
 #endif
 
 extern void __flush_dcache_range(unsigned long start, unsigned long end);
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *page);
 
 #define flush_icache_page(vma, pg)     do { } while(0)

diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h
index b54f6af..9076add 100644 (file)
--- a/arch/x86/include/asm/cacheflush.h
+++ b/arch/x86/include/asm/cacheflush.h
@@ -12,6 +12,7 @@ static inline void flush_cache_range(struct vm_area_struct *vma,
                                     unsigned long start, unsigned long end) { }
 static inline void flush_cache_page(struct vm_area_struct *vma,
                                    unsigned long vmaddr, unsigned long pfn) { }
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 static inline void flush_dcache_page(struct page *page) { }
 static inline void flush_dcache_mmap_lock(struct address_space *mapping) { }
 static inline void flush_dcache_mmap_unlock(struct address_space *mapping) { }

diff --git a/arch/xtensa/include/asm/cacheflush.h b/arch/xtensa/include/asm/cacheflush.h
index b7b8fbe..a508f2f 100644 (file)
--- a/arch/xtensa/include/asm/cacheflush.h
+++ b/arch/xtensa/include/asm/cacheflush.h
@@ -101,6 +101,7 @@ static inline void __invalidate_icache_page_alias(unsigned long virt,
 #define flush_cache_vmap(start,end)    flush_cache_all()
 #define flush_cache_vunmap(start,end)  flush_cache_all()
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page*);
 extern void flush_cache_range(struct vm_area_struct*, ulong, ulong);
 extern void flush_cache_page(struct vm_area_struct*, unsigned long, unsigned long);

diff --git a/block/blk-core.c b/block/blk-core.c
index 71da511..718897e 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2358,6 +2358,25 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
                rq->rq_disk = bio->bi_bdev->bd_disk;
 }
 
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+/**
+ * rq_flush_dcache_pages - Helper function to flush all pages in a request
+ * @rq: the request to be flushed
+ *
+ * Description:
+ *     Flush all pages in @rq.
+ */
+void rq_flush_dcache_pages(struct request *rq)
+{
+       struct req_iterator iter;
+       struct bio_vec *bvec;
+
+       rq_for_each_segment(bvec, rq, iter)
+               flush_dcache_page(bvec->bv_page);
+}
+EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
+#endif
+
 /**
  * blk_lld_busy - Check if underlying low-level drivers of a device are busy
  * @q : the queue of the device being checked

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 8ca17a3..64e2b37 100644 (file)
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -59,12 +59,14 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
                for (; nsect > 0; nsect--, block++, buf += tr->blksize)
                        if (tr->readsect(dev, block, buf))
                                return -EIO;
+               rq_flush_dcache_pages(req);
                return 0;
 
        case WRITE:
                if (!tr->writesect)
                        return -EIO;
 
+               rq_flush_dcache_pages(req);
                for (; nsect > 0; nsect--, block++, buf += tr->blksize)
                        if (tr->writesect(dev, block, buf))
                                return -EIO;

diff --git a/fs/bio.c b/fs/bio.c
index 12da5db..e23a63f 100644 (file)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1393,6 +1393,18 @@ void bio_check_pages_dirty(struct bio *bio)
        }
 }
 
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+void bio_flush_dcache_pages(struct bio *bi)
+{
+       int i;
+       struct bio_vec *bvec;
+
+       bio_for_each_segment(bvec, bi, i)
+               flush_dcache_page(bvec->bv_page);
+}
+EXPORT_SYMBOL(bio_flush_dcache_pages);
+#endif
+
 /**
  * bio_endio - end I/O on a bio
  * @bio:       bio

diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cacheflush.h
index ba4ec39..57b5c3c 100644 (file)
--- a/include/asm-generic/cacheflush.h
+++ b/include/asm-generic/cacheflush.h
@@ -13,6 +13,7 @@
 #define flush_cache_dup_mm(mm)                 do { } while (0)
 #define flush_cache_range(vma, start, end)     do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)     do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)                        do { } while (0)
 #define flush_dcache_mmap_lock(mapping)                do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)      do { } while (0)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 474792b..7fc5606 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -391,6 +391,18 @@ extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
                                 gfp_t, int);
 extern void bio_set_pages_dirty(struct bio *bio);
 extern void bio_check_pages_dirty(struct bio *bio);
+
+#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+# error        "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
+#endif
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+extern void bio_flush_dcache_pages(struct bio *bi);
+#else
+static inline void bio_flush_dcache_pages(struct bio *bi)
+{
+}
+#endif
+
 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
                                 unsigned long, unsigned int, int, gfp_t);
 extern struct bio *bio_copy_user_iov(struct request_queue *,

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1cc0297..e727f6c 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -752,6 +752,17 @@ struct req_iterator {
 #define rq_iter_last(rq, _iter)                                        \
                (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 
+#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+# error        "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
+#endif
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+extern void rq_flush_dcache_pages(struct request *rq);
+#else
+static inline void rq_flush_dcache_pages(struct request *rq)
+{
+}
+#endif
+
 extern int blk_register_queue(struct gendisk *disk);
 extern void blk_unregister_queue(struct gendisk *disk);
 extern void register_disk(struct gendisk *dev);