From 905889bc6c842d18f369bf2834cf7219f32709ae Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 23 Sep 2022 13:28:13 -0700 Subject: btrfs: send: Proactively round up to kmalloc bucket size Instead of discovering the kmalloc bucket size _after_ allocation, round up proactively so the allocation is explicitly made for the full size, allowing the compiler to correctly reason about the resulting size of the buffer through the existing __alloc_size() hint. Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Acked-by: David Sterba Link: https://lore.kernel.org/lkml/20220922133014.GI32411@suse.cz Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220923202822.2667581-8-keescook@chromium.org --- fs/btrfs/send.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 4ef4167072b8..f53e8049473d 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -438,6 +438,11 @@ static int fs_path_ensure_buf(struct fs_path *p, int len) path_len = p->end - p->start; old_buf_len = p->buf_len; + /* + * Allocate to the next largest kmalloc bucket size, to let + * the fast path happen most of the time. + */ + len = kmalloc_size_roundup(len); /* * First time the inline_buf does not suffice */ @@ -451,11 +456,7 @@ static int fs_path_ensure_buf(struct fs_path *p, int len) if (!tmp_buf) return -ENOMEM; p->buf = tmp_buf; - /* - * The real size of the buffer is bigger, this will let the fast path - * happen most of the time - */ - p->buf_len = ksize(p->buf); + p->buf_len = len; if (p->reversed) { tmp_buf = p->buf + old_buf_len - path_len - 1; -- cgit v1.2.3