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

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

[Christophe JAILLET]

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@wanadoo.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

[PATCH 2/2] watch_queue: Fix a memory leak

[Christophe JAILLET]

The 'notes_bitmap' is allocated in 'watch_queue_set_size()' but is never
released.
Free it when 'wqueue' and its other fields are freed.

Fixes: c73be61cede5 ("pipe: Add general notification queue support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
WARNING: This patch is certainly buggy because there is 'rcu'
consideration, but I've nothing better to propose.

It is maybe also completely buggy because freeing reference counted
resources is sometimes puzzling!

So review with care and update as needed (if needed :) )
---
 kernel/watch_queue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c
index 41ea30948c57..36c6822bec86 100644
--- a/kernel/watch_queue.c
+++ b/kernel/watch_queue.c
@@ -372,6 +372,7 @@ static void __put_watch_queue(struct kref *kref)
 	wfilter = rcu_access_pointer(wqueue->filter);
 	if (wfilter)
 		kfree_rcu(wfilter, rcu);
+	bitmap_free(wqueue->notes_bitmap);
 	kfree_rcu(wqueue, rcu);
 }
 
-- 
2.30.2