diff mbox series

[V1,05/10] arch/kmap_atomic: Consolidate duplicate code

Message ID 20200430203845.582900-6-ira.weiny@intel.com (mailing list archive)
State Superseded
Headers show
Series Remove duplicated kmap code | expand

Commit Message

Ira Weiny April 30, 2020, 8:38 p.m. UTC 
From: Ira Weiny <ira.weiny@intel.com>

Every arch has the same code to ensure atomic operations and a check for
!HIGHMEM page.

Remove the duplicate code by defining a core kmap_atomic() which only
calls the arch specific kmap_atomic_high() when the page is high memory.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
Changes from V0:
	consolidate comments
	Use a similar architecture to kmap() and define
		kmap_atomic_high() for architecture specific
		functionality
	Fix 0-day build issue in arch/mips/mm/cache.c
---
 arch/arc/include/asm/highmem.h        |  2 +-
 arch/arc/mm/highmem.c                 |  9 ++-------
 arch/arm/include/asm/highmem.h        |  2 +-
 arch/arm/mm/highmem.c                 |  9 ++-------
 arch/csky/include/asm/highmem.h       |  2 +-
 arch/csky/mm/highmem.c                |  9 ++-------
 arch/microblaze/include/asm/highmem.h |  2 +-
 arch/microblaze/mm/highmem.c          |  6 ------
 arch/mips/include/asm/highmem.h       |  2 +-
 arch/mips/mm/cache.c                  |  2 +-
 arch/mips/mm/highmem.c                | 18 ++----------------
 arch/nds32/include/asm/highmem.h      |  2 +-
 arch/nds32/mm/highmem.c               |  9 ++-------
 arch/powerpc/include/asm/highmem.h    |  2 +-
 arch/powerpc/mm/highmem.c             | 11 -----------
 arch/sparc/include/asm/highmem.h      |  2 +-
 arch/sparc/mm/highmem.c               |  9 ++-------
 arch/x86/include/asm/highmem.h        |  7 +++++--
 arch/x86/mm/highmem_32.c              | 20 --------------------
 arch/xtensa/include/asm/highmem.h     |  2 +-
 arch/xtensa/mm/highmem.c              |  9 ++-------
 include/linux/highmem.h               | 22 ++++++++++++++++++++++
 22 files changed, 51 insertions(+), 107 deletions(-)

Comments

Al Viro May 1, 2020, 2:09 a.m. UTC | #1 
On Thu, Apr 30, 2020 at 01:38:40PM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> Every arch has the same code to ensure atomic operations and a check for
> !HIGHMEM page.
> 
> Remove the duplicate code by defining a core kmap_atomic() which only
> calls the arch specific kmap_atomic_high() when the page is high memory.

Err....  AFAICS, you've just silently changed the semantics for
kmap_atomic_prot() here.  And while most of the callers are converted,
drivers/gpu/drm/ttm/ttm_bo_util.c one is not, so at the very least it's
a bisect hazard...

And I would argue that having kmap_atomic() differ from kmap_atomic_prot()
wrt disabling preempt is asking for trouble.
Christoph Hellwig May 1, 2020, 8:39 a.m. UTC | #2 
On Thu, Apr 30, 2020 at 01:38:40PM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> Every arch has the same code to ensure atomic operations and a check for
> !HIGHMEM page.
> 
> Remove the duplicate code by defining a core kmap_atomic() which only
> calls the arch specific kmap_atomic_high() when the page is high memory.
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/arch/arc/include/asm/highmem.h b/arch/arc/include/asm/highmem.h
index 8387a5596a91..75bd0fa77fe2 100644
--- a/arch/arc/include/asm/highmem.h
+++ b/arch/arc/include/asm/highmem.h
@@ -30,7 +30,7 @@ 
 
 #include <asm/cacheflush.h>
 
-extern void *kmap_atomic(struct page *page);
+extern void *kmap_atomic_high(struct page *page);
 extern void __kunmap_atomic(void *kvaddr);
 
 extern void kmap_init(void);
diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
index 4db13a6b9f3b..0964b011c29f 100644
--- a/arch/arc/mm/highmem.c
+++ b/arch/arc/mm/highmem.c
@@ -49,16 +49,11 @@ 
 extern pte_t * pkmap_page_table;
 static pte_t * fixmap_page_table;
 
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	int idx, cpu_idx;
 	unsigned long vaddr;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	cpu_idx = kmap_atomic_idx_push();
 	idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
 	vaddr = FIXMAP_ADDR(idx);
@@ -68,7 +63,7 @@  void *kmap_atomic(struct page *page)
 
 	return (void *)vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kv)
 {
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
index 736f65283e7b..4edb6db3a5c8 100644
--- a/arch/arm/include/asm/highmem.h
+++ b/arch/arm/include/asm/highmem.h
@@ -60,7 +60,7 @@  static inline void *kmap_high_get(struct page *page)
  * when CONFIG_HIGHMEM is not set.
  */
 #ifdef CONFIG_HIGHMEM
-extern void *kmap_atomic(struct page *page);
+extern void *kmap_atomic_high(struct page *page);
 extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 #endif
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index c700b32350ee..075fdc235091 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -31,18 +31,13 @@  static inline pte_t get_fixmap_pte(unsigned long vaddr)
 	return *ptep;
 }
 
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	unsigned int idx;
 	unsigned long vaddr;
 	void *kmap;
 	int type;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
 	 * There is no cache coherency issue when non VIVT, so force the
@@ -76,7 +71,7 @@  void *kmap_atomic(struct page *page)
 
 	return (void *)vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kvaddr)
 {
diff --git a/arch/csky/include/asm/highmem.h b/arch/csky/include/asm/highmem.h
index be11c5b67122..6807df1232f3 100644
--- a/arch/csky/include/asm/highmem.h
+++ b/arch/csky/include/asm/highmem.h
@@ -32,7 +32,7 @@  extern pte_t *pkmap_page_table;
 
 #define ARCH_HAS_KMAP_FLUSH_TLB
 extern void kmap_flush_tlb(unsigned long addr);
-extern void *kmap_atomic(struct page *page);
+extern void *kmap_atomic_high(struct page *page);
 extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 extern struct page *kmap_atomic_to_page(void *ptr);
diff --git a/arch/csky/mm/highmem.c b/arch/csky/mm/highmem.c
index e9952211264b..63d74b47eee6 100644
--- a/arch/csky/mm/highmem.c
+++ b/arch/csky/mm/highmem.c
@@ -21,16 +21,11 @@  EXPORT_SYMBOL(kmap_flush_tlb);
 
 EXPORT_SYMBOL(kmap);
 
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
@@ -42,7 +37,7 @@  void *kmap_atomic(struct page *page)
 
 	return (void *)vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kvaddr)
 {
diff --git a/arch/microblaze/include/asm/highmem.h b/arch/microblaze/include/asm/highmem.h
index 0c94046f2d58..fe4ad8bac9ae 100644
--- a/arch/microblaze/include/asm/highmem.h
+++ b/arch/microblaze/include/asm/highmem.h
@@ -54,7 +54,7 @@  extern pte_t *pkmap_page_table;
 extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
 extern void __kunmap_atomic(void *kvaddr);
 
-static inline void *kmap_atomic(struct page *page)
+static inline void *kmap_atomic_high(struct page *page)
 {
 	return kmap_atomic_prot(page, kmap_prot);
 }
diff --git a/arch/microblaze/mm/highmem.c b/arch/microblaze/mm/highmem.c
index d7569f77fa15..a14f356b055b 100644
--- a/arch/microblaze/mm/highmem.c
+++ b/arch/microblaze/mm/highmem.c
@@ -38,12 +38,6 @@  void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
-
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
diff --git a/arch/mips/include/asm/highmem.h b/arch/mips/include/asm/highmem.h
index 24e7e7e5cc7b..a515bcf15d4b 100644
--- a/arch/mips/include/asm/highmem.h
+++ b/arch/mips/include/asm/highmem.h
@@ -48,7 +48,7 @@  extern pte_t *pkmap_page_table;
 
 #define ARCH_HAS_KMAP_FLUSH_TLB
 extern void kmap_flush_tlb(unsigned long addr);
-extern void *kmap_atomic(struct page *page);
+extern void *kmap_atomic_high(struct page *page);
 extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 33b409391ddb..f015bb51fab0 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -14,9 +14,9 @@ 
 #include <linux/sched.h>
 #include <linux/syscalls.h>
 #include <linux/mm.h>
+#include <linux/highmem.h>
 
 #include <asm/cacheflush.h>
-#include <asm/highmem.h>
 #include <asm/processor.h>
 #include <asm/cpu.h>
 #include <asm/cpu-features.h>
diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c
index eb8ec8493f2f..2bda56372995 100644
--- a/arch/mips/mm/highmem.c
+++ b/arch/mips/mm/highmem.c
@@ -18,25 +18,11 @@  void kmap_flush_tlb(unsigned long addr)
 }
 EXPORT_SYMBOL(kmap_flush_tlb);
 
-/*
- * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
- * no global lock is needed and because the kmap code must perform a global TLB
- * invalidation when the kmap pool wraps.
- *
- * However when holding an atomic kmap is is not legal to sleep, so atomic
- * kmaps are appropriate for short, tight code paths only.
- */
-
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
@@ -48,7 +34,7 @@  void *kmap_atomic(struct page *page)
 
 	return (void*) vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kvaddr)
 {
diff --git a/arch/nds32/include/asm/highmem.h b/arch/nds32/include/asm/highmem.h
index c93c7368bb3f..28f5e7072c70 100644
--- a/arch/nds32/include/asm/highmem.h
+++ b/arch/nds32/include/asm/highmem.h
@@ -51,7 +51,7 @@  extern void kmap_init(void);
  * when CONFIG_HIGHMEM is not set.
  */
 #ifdef CONFIG_HIGHMEM
-extern void *kmap_atomic(struct page *page);
+extern void *kmap_atomic_high(struct page *page);
 extern void __kunmap_atomic(void *kvaddr);
 extern void *kmap_atomic_pfn(unsigned long pfn);
 extern struct page *kmap_atomic_to_page(void *ptr);
diff --git a/arch/nds32/mm/highmem.c b/arch/nds32/mm/highmem.c
index f9348bec0ecb..f5f3a21460c4 100644
--- a/arch/nds32/mm/highmem.c
+++ b/arch/nds32/mm/highmem.c
@@ -10,18 +10,13 @@ 
 #include <asm/fixmap.h>
 #include <asm/tlbflush.h>
 
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	unsigned int idx;
 	unsigned long vaddr, pte;
 	int type;
 	pte_t *ptep;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	type = kmap_atomic_idx_push();
 
 	idx = type + KM_TYPE_NR * smp_processor_id();
@@ -37,7 +32,7 @@  void *kmap_atomic(struct page *page)
 	return (void *)vaddr;
 }
 
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kvaddr)
 {
diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h
index ba3371977d49..ac0efc2cf08a 100644
--- a/arch/powerpc/include/asm/highmem.h
+++ b/arch/powerpc/include/asm/highmem.h
@@ -62,7 +62,7 @@  extern pte_t *pkmap_page_table;
 extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
 extern void __kunmap_atomic(void *kvaddr);
 
-static inline void *kmap_atomic(struct page *page)
+static inline void *kmap_atomic_high(struct page *page)
 {
 	return kmap_atomic_prot(page, kmap_prot);
 }
diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c
index 320c1672b2ae..f9558ef4b8fa 100644
--- a/arch/powerpc/mm/highmem.c
+++ b/arch/powerpc/mm/highmem.c
@@ -24,22 +24,11 @@ 
 #include <linux/highmem.h>
 #include <linux/module.h>
 
-/*
- * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
- * gives a more generic (and caching) interface. But kmap_atomic can
- * be used in IRQ contexts, so in some (very limited) cases we need
- * it.
- */
 void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
diff --git a/arch/sparc/include/asm/highmem.h b/arch/sparc/include/asm/highmem.h
index 4bdb79fed02c..c96a0603d821 100644
--- a/arch/sparc/include/asm/highmem.h
+++ b/arch/sparc/include/asm/highmem.h
@@ -50,7 +50,7 @@  void kmap_init(void) __init;
 
 #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
 
-void *kmap_atomic(struct page *page);
+void *kmap_atomic_high(struct page *page);
 void __kunmap_atomic(void *kvaddr);
 
 #define flush_cache_kmaps()	flush_cache_all()
diff --git a/arch/sparc/mm/highmem.c b/arch/sparc/mm/highmem.c
index d4a80adea7e5..b53070ab6a31 100644
--- a/arch/sparc/mm/highmem.c
+++ b/arch/sparc/mm/highmem.c
@@ -53,16 +53,11 @@  void __init kmap_init(void)
         kmap_prot = __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE);
 }
 
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	unsigned long vaddr;
 	long idx, type;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
@@ -87,7 +82,7 @@  void *kmap_atomic(struct page *page)
 
 	return (void*) vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kvaddr)
 {
diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
index 90b96594d6c5..72e154e17416 100644
--- a/arch/x86/include/asm/highmem.h
+++ b/arch/x86/include/asm/highmem.h
@@ -58,8 +58,11 @@  extern unsigned long highstart_pfn, highend_pfn;
 #define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
 #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
 
-void *kmap_atomic_prot(struct page *page, pgprot_t prot);
-void *kmap_atomic(struct page *page);
+extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
+void *kmap_atomic_high(struct page *page)
+{
+	return kmap_atomic_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);
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index c4ebfd0ae401..937d2cc40389 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -4,25 +4,11 @@ 
 #include <linux/swap.h> /* for totalram_pages */
 #include <linux/memblock.h>
 
-/*
- * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
- * no global lock is needed and because the kmap code must perform a global TLB
- * invalidation when the kmap pool wraps.
- *
- * However when holding an atomic kmap it is not legal to sleep, so atomic
- * kmaps are appropriate for short, tight code paths only.
- */
 void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
-	pagefault_disable();
-
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
@@ -34,12 +20,6 @@  void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 }
 EXPORT_SYMBOL(kmap_atomic_prot);
 
-void *kmap_atomic(struct page *page)
-{
-	return kmap_atomic_prot(page, kmap_prot);
-}
-EXPORT_SYMBOL(kmap_atomic);
-
 /*
  * This is the same as kmap_atomic() but can map memory that doesn't
  * have a struct page associated with it.
diff --git a/arch/xtensa/include/asm/highmem.h b/arch/xtensa/include/asm/highmem.h
index 5a481f7def0b..d4fb9f78ba32 100644
--- a/arch/xtensa/include/asm/highmem.h
+++ b/arch/xtensa/include/asm/highmem.h
@@ -68,7 +68,7 @@  static inline void flush_cache_kmaps(void)
 	flush_cache_all();
 }
 
-void *kmap_atomic(struct page *page);
+void *kmap_atomic_high(struct page *page);
 void __kunmap_atomic(void *kvaddr);
 
 void kmap_init(void);
diff --git a/arch/xtensa/mm/highmem.c b/arch/xtensa/mm/highmem.c
index 711641c4d214..217f2ebaa298 100644
--- a/arch/xtensa/mm/highmem.c
+++ b/arch/xtensa/mm/highmem.c
@@ -37,16 +37,11 @@  static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
 		color;
 }
 
-void *kmap_atomic(struct page *page)
+void *kmap_atomic_high(struct page *page)
 {
 	enum fixed_addresses idx;
 	unsigned long vaddr;
 
-	preempt_disable();
-	pagefault_disable();
-	if (!PageHighMem(page))
-		return page_address(page);
-
 	idx = kmap_idx(kmap_atomic_idx_push(),
 		       DCACHE_ALIAS(page_to_phys(page)));
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
@@ -57,7 +52,7 @@  void *kmap_atomic(struct page *page)
 
 	return (void *)vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_high);
 
 void __kunmap_atomic(void *kvaddr)
 {
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index ae6e8cb81043..e0106b4f7dbb 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -61,6 +61,28 @@  static inline void kunmap(struct page *page)
 	kunmap_high(page);
 }
 
+/*
+ * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
+ * no global lock is needed and because the kmap code must perform a global TLB
+ * invalidation when the kmap pool wraps.
+ *
+ * However when holding an atomic kmap is is not legal to sleep, so atomic
+ * kmaps are appropriate for short, tight code paths only.
+ *
+ * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+ * gives a more generic (and caching) interface. But kmap_atomic can
+ * be used in IRQ contexts, so in some (very limited) cases we need
+ * it.
+ */
+static inline void *kmap_atomic(struct page *page)
+{
+	preempt_disable();
+	pagefault_disable();
+	if (!PageHighMem(page))
+		return page_address(page);
+	return kmap_atomic_high(page);
+}
+
 /* declarations for linux/mm/highmem.c */
 unsigned int nr_free_highpages(void);
 extern atomic_long_t _totalhigh_pages;