linux-kernel - [PATCH v1 8/8] powerpc/mem: Use kmap_local

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Date:   Wed,  7 Apr 2021 17:22:41 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 8/8] powerpc/mem: Use kmap_local_page() in flushing
 functions

Flushing functions don't rely on preemption being disabled, so
use kmap_local_page() instead of kmap_atomic().

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/mm/mem.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 65b2205839fe..1895bd64191a 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -464,16 +464,16 @@ static void flush_dcache_icache_hugepage(struct page *page)
 {
 	int i;
 	int nr = compound_nr(page);
-	void *start;
 
 	if (!PageHighMem(page)) {
 		for (i = 0; i < nr; i++)
 			__flush_dcache_icache(lowmem_page_address(page + i));
 	} else {
 		for (i = 0; i < nr; i++) {
-			start = kmap_atomic(page+i);
+			void *start = kmap_local_page(page + i);
+
 			__flush_dcache_icache(start);
-			kunmap_atomic(start);
+			kunmap_local(start);
 		}
 	}
 }
@@ -489,9 +489,10 @@ void flush_dcache_icache_page(struct page *page)
 	if (!PageHighMem(page)) {
 		__flush_dcache_icache(lowmem_page_address(page));
 	} else if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
-		void *start = kmap_atomic(page);
+		void *start = kmap_local_page(page);
+
 		__flush_dcache_icache(start);
-		kunmap_atomic(start);
+		kunmap_local(start);
 	} else {
 		flush_dcache_icache_phys(page_to_phys(page));
 	}
@@ -564,11 +565,11 @@ void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
 void flush_icache_user_page(struct vm_area_struct *vma, struct page *page,
 			     unsigned long addr, int len)
 {
-	unsigned long maddr;
+	void *maddr;
 
-	maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
-	flush_icache_range(maddr, maddr + len);
-	kunmap(page);
+	maddr = kmap_local_page(page) + (addr & ~PAGE_MASK);
+	flush_icache_range((unsigned long)maddr, (unsigned long)maddr + len);
+	kunmap_local(maddr);
 }
 
 /*
-- 
2.25.0