linux-kernel - [PATCH 1/2] watch_queue: Use the bitmap API when applicable

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Date:   Sun, 28 Nov 2021 14:58:26 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     dhowells@...hat.com, lukas.bulwahn@...il.com
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH 1/2] watch_queue: Use the bitmap API when applicable

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

While at it, use 'bitmap_fill()' to avoid an explicit 'memset()'

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;
-- 
2.30.2