arch/kunmap_atomic: consolidate duplicate code

Every single architecture (including !CONFIG_HIGHMEM) calls...

	pagefault_enable();
	preempt_enable();

... before returning from __kunmap_atomic().  Lift this code into the
kunmap_atomic() macro.

While we are at it rename __kunmap_atomic() to kunmap_atomic_high() to
be consistent.

[ira.weiny@intel.com: don't enable pagefault/preempt twice]
  Link: http://lkml.kernel.org/r/20200518184843.3029640-1-ira.weiny@intel.com
[akpm@linux-foundation.org: coding style fixes]
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
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: 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>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/20200507150004.1423069-8-ira.weiny@intel.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arc/include/asm/highmem.h

@@ -30,8 +30,6 @@
 
 #include <asm/cacheflush.h>
 
-extern void __kunmap_atomic(void *kvaddr);
-
 extern void kmap_init(void);
 
 static inline void flush_cache_kmaps(void)

arch/arc/mm/highmem.c

@@ -65,7 +65,7 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kv)
+void kunmap_atomic_high(void *kv)
 {
 	unsigned long kvaddr = (unsigned long)kv;
 
@@ -87,11 +87,8 @@ void __kunmap_atomic(void *kv)
 
 		kmap_atomic_idx_pop();
 	}
-
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);
 
 static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
 {

arch/arm/include/asm/highmem.h

@@ -60,7 +60,6 @@ static inline void *kmap_high_get(struct page *page)
  * when CONFIG_HIGHMEM is not set.
  */
 #ifdef CONFIG_HIGHMEM
-extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 #endif
 

arch/arm/mm/highmem.c

@@ -73,7 +73,7 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 	int idx, type;
@@ -95,10 +95,8 @@ void __kunmap_atomic(void *kvaddr)
 		/* this address was obtained through kmap_high_get() */
 		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
 	}
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);
 
 void *kmap_atomic_pfn(unsigned long pfn)
 {

arch/csky/include/asm/highmem.h

@@ -32,7 +32,6 @@ extern pte_t *pkmap_page_table;
 
 #define ARCH_HAS_KMAP_FLUSH_TLB
 extern void kmap_flush_tlb(unsigned long addr);
-extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 extern struct page *kmap_atomic_to_page(void *ptr);
 

arch/csky/mm/highmem.c

@@ -39,13 +39,13 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 	int idx;
 
 	if (vaddr < FIXADDR_START)
-		goto out;
+		return;
 
 #ifdef CONFIG_DEBUG_HIGHMEM
 	idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();
@@ -58,11 +58,8 @@ void __kunmap_atomic(void *kvaddr)
 	(void) idx; /* to kill a warning */
 #endif
 	kmap_atomic_idx_pop();
-out:
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);
 
 /*
  * This is the same as kmap_atomic() but can map memory that doesn't

arch/microblaze/include/asm/highmem.h

@@ -61,7 +61,6 @@ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 
 	return kmap_atomic_high_prot(page, prot);
 }
-extern void __kunmap_atomic(void *kvaddr);
 
 static inline void *kmap_atomic_high(struct page *page)
 {

arch/microblaze/mm/highmem.c

@@ -51,17 +51,14 @@ void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 }
 EXPORT_SYMBOL(kmap_atomic_high_prot);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 	int type;
 	unsigned int idx;
 
-	if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
-		pagefault_enable();
-		preempt_enable();
+	if (vaddr < __fix_to_virt(FIX_KMAP_END))
 		return;
-	}
 
 	type = kmap_atomic_idx();
 
@@ -77,7 +74,5 @@ void __kunmap_atomic(void *kvaddr)
 	local_flush_tlb_page(NULL, vaddr);
 
 	kmap_atomic_idx_pop();
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);

arch/mips/include/asm/highmem.h

@@ -48,7 +48,6 @@ extern pte_t *pkmap_page_table;
 
 #define ARCH_HAS_KMAP_FLUSH_TLB
 extern void kmap_flush_tlb(unsigned long addr);
-extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 
 #define flush_cache_kmaps()	BUG_ON(cpu_has_dc_aliases)

arch/mips/mm/cache.c

@@ -103,7 +103,7 @@ void __flush_dcache_page(struct page *page)
 	flush_data_cache_page(addr);
 
 	if (PageHighMem(page))
-		__kunmap_atomic((void *)addr);
+		kunmap_atomic((void *)addr);
 }
 
 EXPORT_SYMBOL(__flush_dcache_page);
@@ -146,7 +146,7 @@ void __update_cache(unsigned long address, pte_t pte)
 			flush_data_cache_page(addr);
 
 		if (PageHighMem(page))
-			__kunmap_atomic((void *)addr);
+			kunmap_atomic((void *)addr);
 
 		ClearPageDcacheDirty(page);
 	}

arch/mips/mm/highmem.c

@@ -36,16 +36,13 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 	int type __maybe_unused;
 
-	if (vaddr < FIXADDR_START) { // FIXME
-		pagefault_enable();
-		preempt_enable();
+	if (vaddr < FIXADDR_START)
 		return;
-	}
 
 	type = kmap_atomic_idx();
 #ifdef CONFIG_DEBUG_HIGHMEM
@@ -63,10 +60,8 @@ void __kunmap_atomic(void *kvaddr)
 	}
 #endif
 	kmap_atomic_idx_pop();
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);
 
 /*
  * This is the same as kmap_atomic() but can map memory that doesn't

arch/nds32/include/asm/highmem.h

@@ -51,7 +51,6 @@ extern void kmap_init(void);
  * when CONFIG_HIGHMEM is not set.
  */
 #ifdef CONFIG_HIGHMEM
-extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 extern struct page *kmap_atomic_to_page(void *ptr);
 #endif

arch/nds32/mm/highmem.c

@@ -33,7 +33,7 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	if (kvaddr >= (void *)FIXADDR_START) {
 		unsigned long vaddr = (unsigned long)kvaddr;
@@ -44,7 +44,5 @@ void __kunmap_atomic(void *kvaddr)
 		ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
 		set_pte(ptep, 0);
 	}
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);

arch/parisc/include/asm/cacheflush.h

@@ -122,11 +122,9 @@ static inline void *kmap_atomic(struct page *page)
 	return page_address(page);
 }
 
-static inline void __kunmap_atomic(void *addr)
+static inline void kunmap_atomic_high(void *addr)
 {
 	flush_kernel_dcache_page_addr(addr);
-	pagefault_enable();
-	preempt_enable();
 }
 
 #define kmap_atomic_prot(page, prot)	kmap_atomic(page)

arch/powerpc/include/asm/highmem.h

@@ -69,7 +69,6 @@ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 
 	return kmap_atomic_high_prot(page, prot);
 }
-extern void __kunmap_atomic(void *kvaddr);
 
 static inline void *kmap_atomic_high(struct page *page)
 {

arch/powerpc/mm/highmem.c

@@ -40,15 +40,12 @@ void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 }
 EXPORT_SYMBOL(kmap_atomic_high_prot);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 
-	if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
-		pagefault_enable();
-		preempt_enable();
+	if (vaddr < __fix_to_virt(FIX_KMAP_END))
 		return;
-	}
 
 	if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM)) {
 		int type = kmap_atomic_idx();
@@ -66,7 +63,5 @@ void __kunmap_atomic(void *kvaddr)
 	}
 
 	kmap_atomic_idx_pop();
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);

arch/sparc/include/asm/highmem.h

@@ -50,8 +50,6 @@ void kmap_init(void) __init;
 
 #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
 
-void __kunmap_atomic(void *kvaddr);
-
 #define flush_cache_kmaps()	flush_cache_all()
 
 #endif /* __KERNEL__ */

arch/sparc/mm/highmem.c

@@ -84,16 +84,13 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 	int type;
 
-	if (vaddr < FIXADDR_START) { // FIXME
-		pagefault_enable();
-		preempt_enable();
+	if (vaddr < FIXADDR_START)
 		return;
-	}
 
 	type = kmap_atomic_idx();
 
@@ -126,7 +123,5 @@ void __kunmap_atomic(void *kvaddr)
 #endif
 
 	kmap_atomic_idx_pop();
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);

arch/x86/include/asm/highmem.h

@@ -72,7 +72,6 @@ static inline void *kmap_atomic_high(struct page *page)
 {
 	return kmap_atomic_high_prot(page, kmap_prot);
 }
-void __kunmap_atomic(void *kvaddr);
 void *kmap_atomic_pfn(unsigned long pfn);
 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
 

arch/x86/mm/highmem_32.c

@@ -30,7 +30,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
 }
 EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 
@@ -60,11 +60,8 @@ void __kunmap_atomic(void *kvaddr)
 		BUG_ON(vaddr >= (unsigned long)high_memory);
 	}
 #endif
-
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);
 
 void __init set_highmem_pages_init(void)
 {

arch/xtensa/include/asm/highmem.h

@@ -68,8 +68,6 @@ static inline void flush_cache_kmaps(void)
 	flush_cache_all();
 }
 
-void __kunmap_atomic(void *kvaddr);
-
 void kmap_init(void);
 
 #endif

arch/xtensa/mm/highmem.c

@@ -54,7 +54,7 @@ void *kmap_atomic_high(struct page *page)
 }
 EXPORT_SYMBOL(kmap_atomic_high);
 
-void __kunmap_atomic(void *kvaddr)
+void kunmap_atomic_high(void *kvaddr)
 {
 	if (kvaddr >= (void *)FIXADDR_START &&
 	    kvaddr < (void *)FIXADDR_TOP) {
@@ -73,11 +73,8 @@ void __kunmap_atomic(void *kvaddr)
 
 		kmap_atomic_idx_pop();
 	}
-
-	pagefault_enable();
-	preempt_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic);
+EXPORT_SYMBOL(kunmap_atomic_high);
 
 void __init kmap_init(void)
 {

include/linux/highmem.h

@@ -33,6 +33,7 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
 
 #ifdef CONFIG_HIGHMEM
 extern void *kmap_atomic_high(struct page *page);
+extern void kunmap_atomic_high(void *kvaddr);
 #include <asm/highmem.h>
 
 #ifndef ARCH_HAS_KMAP_FLUSH_TLB
@@ -151,10 +152,12 @@ static inline void *kmap_atomic(struct page *page)
 }
 #define kmap_atomic_prot(page, prot)	kmap_atomic(page)
 
-static inline void __kunmap_atomic(void *addr)
+static inline void kunmap_atomic_high(void *addr)
 {
-	pagefault_enable();
-	preempt_enable();
+	/*
+	 * Nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic()
+	 * handles re-enabling faults + preemption
+	 */
 }
 
 #define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
@@ -204,7 +207,9 @@ static inline void kmap_atomic_idx_pop(void)
 #define kunmap_atomic(addr)                                     \
 do {                                                            \
 	BUILD_BUG_ON(__same_type((addr), struct page *));       \
-	__kunmap_atomic(addr);                                  \
+	kunmap_atomic_high(addr);                                  \
+	pagefault_enable();                                     \
+	preempt_enable();                                       \
 } while (0)