From: Arnd Bergmann <[email protected]> Arm has stopped setting ARCH_NEEDS_KMAP_HIGH_GET, so this is handled using the same wrappers across all architectures now, which leaves room for simplification.
Replace lock_kmap()/unlock_kmap() with open-coded spinlocks and drop the now empty arch_kmap_local_high_get() and kmap_high_unmap_local() helpers. Signed-off-by: Arnd Bergmann <[email protected]> --- mm/highmem.c | 100 ++++++--------------------------------------------- 1 file changed, 10 insertions(+), 90 deletions(-) diff --git a/mm/highmem.c b/mm/highmem.c index b5c8e4c2d5d4..bdeec56471c9 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -143,25 +143,6 @@ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock); pte_t *pkmap_page_table; -/* - * Most architectures have no use for kmap_high_get(), so let's abstract - * the disabling of IRQ out of the locking in that case to save on a - * potential useless overhead. - */ -#ifdef ARCH_NEEDS_KMAP_HIGH_GET -#define lock_kmap() spin_lock_irq(&kmap_lock) -#define unlock_kmap() spin_unlock_irq(&kmap_lock) -#define lock_kmap_any(flags) spin_lock_irqsave(&kmap_lock, flags) -#define unlock_kmap_any(flags) spin_unlock_irqrestore(&kmap_lock, flags) -#else -#define lock_kmap() spin_lock(&kmap_lock) -#define unlock_kmap() spin_unlock(&kmap_lock) -#define lock_kmap_any(flags) \ - do { spin_lock(&kmap_lock); (void)(flags); } while (0) -#define unlock_kmap_any(flags) \ - do { spin_unlock(&kmap_lock); (void)(flags); } while (0) -#endif - struct page *__kmap_to_page(void *vaddr) { unsigned long base = (unsigned long) vaddr & PAGE_MASK; @@ -237,9 +218,9 @@ static void flush_all_zero_pkmaps(void) void __kmap_flush_unused(void) { - lock_kmap(); + spin_lock(&kmap_lock); flush_all_zero_pkmaps(); - unlock_kmap(); + spin_unlock(&kmap_lock); } static inline unsigned long map_new_virtual(struct page *page) @@ -273,10 +254,10 @@ static inline unsigned long map_new_virtual(struct page *page) __set_current_state(TASK_UNINTERRUPTIBLE); add_wait_queue(pkmap_map_wait, &wait); - unlock_kmap(); + spin_unlock(&kmap_lock); schedule(); remove_wait_queue(pkmap_map_wait, &wait); - lock_kmap(); + spin_lock(&kmap_lock); /* Somebody else might have mapped it while we slept */ if (page_address(page)) @@ -312,60 +293,32 @@ void *kmap_high(struct page *page) * For highmem pages, we can't trust "virtual" until * after we have the lock. */ - lock_kmap(); + spin_lock(&kmap_lock); vaddr = (unsigned long)page_address(page); if (!vaddr) vaddr = map_new_virtual(page); pkmap_count[PKMAP_NR(vaddr)]++; BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2); - unlock_kmap(); + spin_unlock(&kmap_lock); return (void *) vaddr; } EXPORT_SYMBOL(kmap_high); -#ifdef ARCH_NEEDS_KMAP_HIGH_GET -/** - * kmap_high_get - pin a highmem page into memory - * @page: &struct page to pin - * - * Returns the page's current virtual memory address, or NULL if no mapping - * exists. If and only if a non null address is returned then a - * matching call to kunmap_high() is necessary. - * - * This can be called from any context. - */ -void *kmap_high_get(const struct page *page) -{ - unsigned long vaddr, flags; - - lock_kmap_any(flags); - vaddr = (unsigned long)page_address(page); - if (vaddr) { - BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 1); - pkmap_count[PKMAP_NR(vaddr)]++; - } - unlock_kmap_any(flags); - return (void *) vaddr; -} -#endif - /** * kunmap_high - unmap a highmem page into memory * @page: &struct page to unmap * - * If ARCH_NEEDS_KMAP_HIGH_GET is not defined then this may be called - * only from user context. + * This may be called only from user context. */ void kunmap_high(const struct page *page) { unsigned long vaddr; unsigned long nr; - unsigned long flags; int need_wakeup; unsigned int color = get_pkmap_color(page); wait_queue_head_t *pkmap_map_wait; - lock_kmap_any(flags); + spin_lock(&kmap_lock); vaddr = (unsigned long)page_address(page); BUG_ON(!vaddr); nr = PKMAP_NR(vaddr); @@ -392,7 +345,7 @@ void kunmap_high(const struct page *page) pkmap_map_wait = get_pkmap_wait_queue_head(color); need_wakeup = waitqueue_active(pkmap_map_wait); } - unlock_kmap_any(flags); + spin_unlock(&kmap_lock); /* do wake-up, if needed, race-free outside of the spin lock */ if (need_wakeup) @@ -507,30 +460,11 @@ static inline void kmap_local_idx_pop(void) #define arch_kmap_local_unmap_idx(idx, vaddr) kmap_local_calc_idx(idx) #endif -#ifndef arch_kmap_local_high_get -static inline void *arch_kmap_local_high_get(const struct page *page) -{ - return NULL; -} -#endif - #ifndef arch_kmap_local_set_pte #define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev) \ set_pte_at(mm, vaddr, ptep, ptev) #endif -/* Unmap a local mapping which was obtained by kmap_high_get() */ -static inline bool kmap_high_unmap_local(unsigned long vaddr) -{ -#ifdef ARCH_NEEDS_KMAP_HIGH_GET - if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) { - kunmap_high(pte_page(ptep_get(&pkmap_page_table[PKMAP_NR(vaddr)]))); - return true; - } -#endif - return false; -} - static pte_t *__kmap_pte; static pte_t *kmap_get_pte(unsigned long vaddr, int idx) @@ -574,8 +508,6 @@ EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot); void *__kmap_local_page_prot(const struct page *page, pgprot_t prot) { - void *kmap; - /* * To broaden the usage of the actual kmap_local() machinery always map * pages when debugging is enabled and the architecture has no problems @@ -584,11 +516,6 @@ void *__kmap_local_page_prot(const struct page *page, pgprot_t prot) if (!IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) && !PageHighMem(page)) return page_address(page); - /* Try kmap_high_get() if architecture has it enabled */ - kmap = arch_kmap_local_high_get(page); - if (kmap) - return kmap; - return __kmap_local_pfn_prot(page_to_pfn(page), prot); } EXPORT_SYMBOL(__kmap_local_page_prot); @@ -606,14 +533,7 @@ void kunmap_local_indexed(const void *vaddr) WARN_ON_ONCE(1); return; } - /* - * Handle mappings which were obtained by kmap_high_get() - * first as the virtual address of such mappings is below - * PAGE_OFFSET. Warn for all other addresses which are in - * the user space part of the virtual address space. - */ - if (!kmap_high_unmap_local(addr)) - WARN_ON_ONCE(addr < PAGE_OFFSET); + WARN_ON_ONCE(addr < PAGE_OFFSET); return; } -- 2.39.5
