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From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
	mingo@kernel.org, jiangshanlai@gmail.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
	paul.gortmaker@windriver.com, Yury Norov <yury.norov@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH lib/bitmap 5/9] lib: bitmap: move ERANGE check from set_region to check_region
Date: Wed,  3 Mar 2021 15:56:12 -0800	[thread overview]
Message-ID: <20210303235616.22093-5-paulmck@kernel.org> (raw)
In-Reply-To: <20210303235526.GA21868@paulmck-ThinkPad-P72>

From: Paul Gortmaker <paul.gortmaker@windriver.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@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.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


  parent reply	other threads:[~2021-03-04  0:27 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-03 23:55 [PATCH tip/core/rcu 0/9] Add bitmap (thus CPU) ranges Paul E. McKenney
2021-03-03 23:56 ` [PATCH lib/bitmap 1/9] lib: test_bitmap: clearly separate ERANGE from EINVAL tests paulmck
2021-03-03 23:56 ` [PATCH lib/bitmap 2/9] lib: test_bitmap: add tests to trigger ERANGE case paulmck
2021-03-03 23:56 ` [PATCH lib/bitmap 3/9] lib: test_bitmap: add more start-end:offset/len tests paulmck
2021-03-03 23:56 ` [PATCH lib/bitmap 4/9] lib: bitmap: fold nbits into region struct paulmck
2021-03-03 23:56 ` paulmck [this message]
2021-03-03 23:56 ` [PATCH lib/bitmap 6/9] lib: bitmap: support "N" as an alias for size of bitmap paulmck
2021-03-03 23:56 ` [PATCH lib/bitmap 7/9] lib: test_bitmap: add tests for "N" alias paulmck
2021-03-03 23:56 ` [PATCH lib/bitmap 8/9] rcu: deprecate "all" option to rcu_nocbs= paulmck
2021-03-03 23:56 ` [PATCH lib/bitmap 9/9] rcutorture: Use "all" and "N" in "nohz_full" and "rcu_nocbs" paulmck

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