Replace a hand-coded overflow check with a specialised function. Even though compilers are smart enough to generate identical binary (i.e. check carry bit), but it's more foolproof and conveys the intention better. Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- fs/io_uring.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b324f7c7a5cc..f30580f59070 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2802,8 +2802,8 @@ static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) size_t len = req->rw.len; struct io_mapped_ubuf *imu; u16 index, buf_index = req->buf_index; + u64 buf_end, buf_addr = req->rw.addr; size_t offset; - u64 buf_addr; if (unlikely(buf_index >= ctx->nr_user_bufs)) return -EFAULT; @@ -2811,11 +2811,10 @@ static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) imu = &ctx->user_bufs[index]; buf_addr = req->rw.addr; - /* overflow */ - if (buf_addr + len < buf_addr) + if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) return -EFAULT; /* not inside the mapped region */ - if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) + if (buf_addr < imu->ubuf || buf_end > imu->ubuf + imu->len) return -EFAULT; /* -- 2.24.0
