From b8c015598c8ef9195b8a2a5089e275c4f64ca999 Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Thu, 30 Jun 2022 02:12:20 -0700 Subject: [PATCH] io_uring: allow 0 length for buffer select If user gives 0 for length, we can set it from the available buffer size. Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220630091231.1456789-2-dylany@fb.com Signed-off-by: Jens Axboe --- io_uring/kbuf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 5e00f16e89b8..e538fa7cb727 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -115,7 +115,7 @@ static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len, kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list); list_del(&kbuf->list); - if (*len > kbuf->len) + if (*len == 0 || *len > kbuf->len) *len = kbuf->len; req->flags |= REQ_F_BUFFER_SELECTED; req->kbuf = kbuf; @@ -145,7 +145,7 @@ static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len, buf = page_address(bl->buf_pages[index]); buf += off; } - if (*len > buf->len) + if (*len == 0 || *len > buf->len) *len = buf->len; req->flags |= REQ_F_BUFFER_RING; req->buf_list = bl; -- 2.34.1