linux-kernel - [PATCH] watch_queue: Use the bitmap API when applicable

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Message-Id: <58a5271107adaa8dc8df32bd8e6b97145caf3b04.1640337380.git.christophe.jaillet@wanadoo.fr>
Date:   Fri, 24 Dec 2021 10:17:14 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     lukas.bulwahn@...il.com, dhowells@...hat.com
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] watch_queue: Use the bitmap API when applicable

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

Also change a memset(0xff) into an equivalent bitmap_fill() to keep
consistency.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
---
 kernel/watch_queue.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c
index 9c9eb20dd2c5..41ea30948c57 100644
--- a/kernel/watch_queue.c
+++ b/kernel/watch_queue.c
@@ -219,7 +219,6 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes)
 	struct page **pages;
 	unsigned long *bitmap;
 	unsigned long user_bufs;
-	unsigned int bmsize;
 	int ret, i, nr_pages;
 
 	if (!wqueue)
@@ -258,13 +257,11 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes)
 		pages[i]->index = i * WATCH_QUEUE_NOTES_PER_PAGE;
 	}
 
-	bmsize = (nr_notes + BITS_PER_LONG - 1) / BITS_PER_LONG;
-	bmsize *= sizeof(unsigned long);
-	bitmap = kmalloc(bmsize, GFP_KERNEL);
+	bitmap = bitmap_alloc(nr_notes, GFP_KERNEL);
 	if (!bitmap)
 		goto error_p;
 
-	memset(bitmap, 0xff, bmsize);
+	bitmap_fill(bitmap, nr_notes);
 	wqueue->notes = pages;
 	wqueue->notes_bitmap = bitmap;
 	wqueue->nr_pages = nr_pages;
-- 
2.32.0