linux-kernel - [PATCH v2] xen-blkfront: Use the bitmap API when applicable

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Message-Id: <d6f31db1d2542e1b4ba66d4cea80d3891678aa5a.1638476031.git.christophe.jaillet@wanadoo.fr>
Date:   Thu,  2 Dec 2021 21:16:04 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     boris.ostrovsky@...cle.com, jgross@...e.com,
        sstabellini@...nel.org, roger.pau@...rix.com, axboe@...nel.dk
Cc:     xen-devel@...ts.xenproject.org, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH v2] xen-blkfront: Use the bitmap API when applicable

Use 'bitmap_zalloc()' to simplify code, improve the semantic and avoid some
open-coded arithmetic in allocator arguments.

Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

Use 'bitmap_copy()' to avoid an explicit 'memcpy()'

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
v1 --> v2: change another kfree into bitmap_free
---
 drivers/block/xen-blkfront.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 700c765a759a..69cf13608ce0 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -442,22 +442,20 @@ static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
 	if (end > nr_minors) {
 		unsigned long *bitmap, *old;
 
-		bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
-				 GFP_KERNEL);
+		bitmap = bitmap_zalloc(end, GFP_KERNEL);
 		if (bitmap == NULL)
 			return -ENOMEM;
 
 		spin_lock(&minor_lock);
 		if (end > nr_minors) {
 			old = minors;
-			memcpy(bitmap, minors,
-			       BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
+			bitmap_copy(bitmap, minors, nr_minors);
 			minors = bitmap;
 			nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
 		} else
 			old = bitmap;
 		spin_unlock(&minor_lock);
-		kfree(old);
+		bitmap_free(old);
 	}
 
 	spin_lock(&minor_lock);
@@ -2610,7 +2608,7 @@ static void __exit xlblk_exit(void)
 
 	xenbus_unregister_driver(&blkfront_driver);
 	unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
-	kfree(minors);
+	bitmap_free(minors);
 }
 module_exit(xlblk_exit);
 
-- 
2.30.2