linux-kernel - [PATCH lib/bitmap 5/9] lib: bitmap: move ERANGE check from set_region to check

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Message-Id: <20210303235616.22093-5-paulmck@kernel.org>
Date:   Wed,  3 Mar 2021 15:56:12 -0800
From:   paulmck@...nel.org
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
        jiangshanlai@...il.com, akpm@...ux-foundation.org,
        mathieu.desnoyers@...icios.com, josh@...htriplett.org,
        tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
        dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
        oleg@...hat.com, joel@...lfernandes.org,
        paul.gortmaker@...driver.com, Yury Norov <yury.norov@...il.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: [PATCH lib/bitmap 5/9] lib: bitmap: move ERANGE check from set_region to check_region

From: Paul Gortmaker <paul.gortmaker@...driver.com>

It makes sense to do all the checks in check_region() and not 1/2
in check_region and 1/2 in set_region.

Since set_region is called immediately after check_region, the net
effect on runtime is zero, but it gets rid of an if (...) return...

Cc: Yury Norov <yury.norov@...il.com>
Cc: Rasmus Villemoes <linux@...musvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Acked-by: Yury Norov <yury.norov@...il.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 lib/bitmap.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 162e285..833f152a 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -500,17 +500,12 @@ struct region {
 	unsigned int nbits;
 };
 
-static int bitmap_set_region(const struct region *r, unsigned long *bitmap)
+static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
 {
 	unsigned int start;
 
-	if (r->end >= r->nbits)
-		return -ERANGE;
-
 	for (start = r->start; start <= r->end; start += r->group_len)
 		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
-
-	return 0;
 }
 
 static int bitmap_check_region(const struct region *r)
@@ -518,6 +513,9 @@ static int bitmap_check_region(const struct region *r)
 	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
 		return -EINVAL;
 
+	if (r->end >= r->nbits)
+		return -ERANGE;
+
 	return 0;
 }
 
@@ -656,9 +654,7 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
 		if (ret)
 			return ret;
 
-		ret = bitmap_set_region(&r, maskp);
-		if (ret)
-			return ret;
+		bitmap_set_region(&r, maskp);
 	}
 
 	return 0;
-- 
2.9.5