linux-kernel - [PATCH v5 2/5] vduse: Use memcpy_{to,from}_page() in do

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Date:   Wed,  3 Aug 2022 12:55:20 +0800
From:   Xie Yongji <xieyongji@...edance.com>
To:     jasowang@...hat.com, mst@...hat.com, xiaodong.liu@...el.com,
        maxime.coquelin@...hat.com, stefanha@...hat.com
Cc:     songmuchun@...edance.com,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, Xie Yongji <xieyongji@...edance.com>
Subject: [PATCH v5 2/5] vduse: Use memcpy_{to,from}_page() in do_bounce()

kmap_atomic() is being deprecated in favor of kmap_local_page().

The use of kmap_atomic() in do_bounce() is all thread local therefore
kmap_local_page() is a sufficient replacement.

Convert to kmap_local_page() but, instead of open coding it,
use the helpers memcpy_to_page() and memcpy_from_page().

Signed-off-by: Xie Yongji <xieyongji@...edance.com>
Acked-by: Jason Wang <jasowang@...hat.com>
Reviewed-by: Muchun Song <songmuchun@...edance.com>
---
 drivers/vdpa/vdpa_user/iova_domain.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index bca1f0b8850c..50d7c08d5450 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -138,18 +138,17 @@ static void do_bounce(phys_addr_t orig, void *addr, size_t size,
 {
 	unsigned long pfn = PFN_DOWN(orig);
 	unsigned int offset = offset_in_page(orig);
-	char *buffer;
+	struct page *page;
 	unsigned int sz = 0;
 
 	while (size) {
 		sz = min_t(size_t, PAGE_SIZE - offset, size);
 
-		buffer = kmap_atomic(pfn_to_page(pfn));
+		page = pfn_to_page(pfn);
 		if (dir == DMA_TO_DEVICE)
-			memcpy(addr, buffer + offset, sz);
+			memcpy_from_page(addr, page, offset, sz);
 		else
-			memcpy(buffer + offset, addr, sz);
-		kunmap_atomic(buffer);
+			memcpy_to_page(page, offset, addr, sz);
 
 		size -= sz;
 		pfn++;
-- 
2.20.1