linux-kernel - [PATCH v2] lib/test_bpf: Call page_address() on page acquired with GFP

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Date:   Tue, 13 Jun 2023 00:17:56 -0700
From:   Sumitra Sharma <sumitraartsy@...il.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...ux.dev>,
        Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Stanislav Fomichev <sdf@...gle.com>,
        Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Ira Weiny <ira.weiny@...el.com>, Fabio <fmdefrancesco@...il.com>,
        Deepak R Varma <drv@...lo.com>
Subject: [PATCH v2] lib/test_bpf: Call page_address() on page acquired with
 GFP_KERNEL flag

generate_test_data() acquires a page with alloc_page(GFP_KERNEL). Pages
allocated with GFP_KERNEL cannot come from Highmem. This is why
there is no need to call kmap() on them.

Therefore, use a plain page_address() on that page.

Suggested-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
Signed-off-by: Sumitra Sharma <sumitraartsy@...il.com>
---

Changes in v2: 
	- Remove the kmap() call and call page_address() instead.
	- Change the commit subject and message.

 lib/test_bpf.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index ade9ac672adb..70fcd0bcf14b 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -14388,11 +14388,10 @@ static void *generate_test_data(struct bpf_test *test, int sub)
 		if (!page)
 			goto err_kfree_skb;
 
-		ptr = kmap(page);
+		ptr = page_address(page);
 		if (!ptr)
 			goto err_free_page;
 		memcpy(ptr, test->frag_data, MAX_DATA);
-		kunmap(page);
 		skb_add_rx_frag(skb, 0, page, 0, MAX_DATA, MAX_DATA);
 	}
 
-- 
2.25.1