parisc/kmap: remove duplicate kmap code

parisc reimplements the kmap calls except to flush its dcache.  This is
arguably an abuse of kmap but regardless it is messy and confusing.

Remove the duplicate code and have parisc define ARCH_HAS_FLUSH_ON_KUNMAP
for a kunmap_flush_on_unmap() architecture specific call to flush the
cache.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-14-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/parisc/include/asm/cacheflush.h

@@ -100,35 +100,11 @@ flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vma
 	}
 }
 
-#include <asm/kmap_types.h>
-
-#define ARCH_HAS_KMAP
-
-static inline void *kmap(struct page *page)
-{
-	might_sleep();
-	return page_address(page);
-}
-
-static inline void kunmap(struct page *page)
-{
-	flush_kernel_dcache_page_addr(page_address(page));
-}
-
-static inline void *kmap_atomic(struct page *page)
-{
-	preempt_disable();
-	pagefault_disable();
-	return page_address(page);
-}
-
-static inline void kunmap_atomic_high(void *addr)
+#define ARCH_HAS_FLUSH_ON_KUNMAP
+static inline void kunmap_flush_on_unmap(void *addr)
 {
 	flush_kernel_dcache_page_addr(addr);
 }
 
-#define kmap_atomic_prot(page, prot)	kmap_atomic(page)
-#define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
-
 #endif /* _PARISC_CACHEFLUSH_H */
 

include/linux/highmem.h

@@ -130,7 +130,6 @@ static inline struct page *kmap_to_page(void *addr)
 
 static inline unsigned long totalhigh_pages(void) { return 0UL; }
 
-#ifndef ARCH_HAS_KMAP
 static inline void *kmap(struct page *page)
 {
 	might_sleep();
@@ -143,6 +142,9 @@ static inline void kunmap_high(struct page *page)
 
 static inline void kunmap(struct page *page)
 {
+#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+	kunmap_flush_on_unmap(page_address(page));
+#endif
 }
 
 static inline void *kmap_atomic(struct page *page)
@@ -156,15 +158,17 @@ static inline void *kmap_atomic(struct page *page)
 static inline void kunmap_atomic_high(void *addr)
 {
 	/*
-	 * Nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic()
+	 * Mostly nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic()
 	 * handles re-enabling faults + preemption
 	 */
+#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+	kunmap_flush_on_unmap(addr);
+#endif
 }
 
 #define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
 
 #define kmap_flush_unused()	do {} while(0)
-#endif
 
 #endif /* CONFIG_HIGHMEM */