linux-kernel - [PATCH v2 net-next 3/6] lib/test_bitmap: verify intermediate arr32 when converting <-> bitmap

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Date:   Tue, 18 Oct 2022 16:00:24 +0200
From:   Alexander Lobakin <alexandr.lobakin@...el.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Alexander Lobakin <alexandr.lobakin@...el.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 net-next 3/6] lib/test_bitmap: verify intermediate arr32 when converting <-> bitmap

When testing converting bitmaps from/to arr32, use
bitmap_validate_arr32() to test whether the tail of the intermediate
array was cleared correctly. Previously there were checks only for
the actual bitmap generated with the double-conversion.
Note that we pass bitmap_arr32_size() instead of `sizeof(arr)`, as
we poison the bytes past the last used word with 0xa5s. Also, for
@nbits == 0, the validation function must return false, account that
case as well.

Signed-off-by: Alexander Lobakin <alexandr.lobakin@...el.com>
---
 lib/test_bitmap.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index a8005ad3bd58..c40ab3dfa776 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -605,6 +605,7 @@ static void __init test_bitmap_arr32(void)
 	unsigned int nbits, next_bit;
 	u32 arr[EXP1_IN_BITS / 32];
 	DECLARE_BITMAP(bmap2, EXP1_IN_BITS);
+	bool valid;
 
 	memset(arr, 0xa5, sizeof(arr));
 
@@ -620,6 +621,9 @@ static void __init test_bitmap_arr32(void)
 				" tail is not safely cleared: %d\n",
 				nbits, next_bit);
 
+		valid = bitmap_validate_arr32(arr, bitmap_arr32_size(nbits), nbits);
+		expect_eq_uint(!!nbits, valid);
+
 		if (nbits < EXP1_IN_BITS - 32)
 			expect_eq_uint(arr[DIV_ROUND_UP(nbits, 32)],
 								0xa5a5a5a5);
-- 
2.37.3