From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB968397E84; Mon, 23 Mar 2026 14:04:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774274655; cv=none; b=d1MCdYfOa13hDB2iWar53B/w8NJWEiT8NnaLcD44ncai3Rt2DFZtpdatFU4HxQRLszKqD5GKvR/TDCA4UWuBh5UxuyZ1gTCgti7ux0yOB1RWWufVNi2oer7xHZL+tPiPC2xucdvzGzRGSNvYOdZPizvPGWf4ZN/BjWw/EGAqexU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774274655; c=relaxed/simple; bh=j8AXq12N6GuRIn3hcNu2b9aNf6xytIuU/QFAobSKAIA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ISA4MZMWe2MfL2ViEtctl1HcLkwOj6xcR6EzLnVjzgtZwNr5/RBPuVszP/a9gv/wIZiHqc5yJ3/WLSKt0m6g1WtdZbORBPHxFmIwMzJ5qpGzkyTd4i+z+fCyRVHKi7OdNVreiGawiEql3KVYJT7l3/BMoi14V2Jbtz/dnqXIk+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xqPAJ+Rd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xqPAJ+Rd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FD33C4CEF7; Mon, 23 Mar 2026 14:04:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774274654; bh=j8AXq12N6GuRIn3hcNu2b9aNf6xytIuU/QFAobSKAIA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xqPAJ+RdX1zFtcD7QP+ukiG9Uhk17B6vC3GSDp+tTJXbdzL8Sl1tK8FOM3Oi116hN 1nvIFpLZYPAbR9tm4ZUnCDJUVIVKXKOoHzZqj8gDNSfR1ETHt+u+tNo5YGueAXzzcP CxTHj/vyWBg9ngQuGhBSJ2YHzsS1YeGszj+sF2J0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Martin Michaelis , Jens Axboe Subject: [PATCH 6.18 065/212] io_uring/kbuf: propagate BUF_MORE through early buffer commit path Date: Mon, 23 Mar 2026 14:44:46 +0100 Message-ID: <20260323134505.827133664@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134503.770111826@linuxfoundation.org> References: <20260323134503.770111826@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe commit 418eab7a6f3c002d8e64d6e95ec27118017019af upstream. When io_should_commit() returns true (eg for non-pollable files), buffer commit happens at buffer selection time and sel->buf_list is set to NULL. When __io_put_kbufs() generates CQE flags at completion time, it calls __io_put_kbuf_ring() which finds a NULL buffer_list and hence cannot determine whether the buffer was consumed or not. This means that IORING_CQE_F_BUF_MORE is never set for non-pollable input with incrementally consumed buffers. Likewise for io_buffers_select(), which always commits upfront and discards the return value of io_kbuf_commit(). Add REQ_F_BUF_MORE to store the result of io_kbuf_commit() during early commit. Then __io_put_kbuf_ring() can check this flag and set IORING_F_BUF_MORE accordingy. Reported-by: Martin Michaelis Cc: stable@vger.kernel.org Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Link: https://github.com/axboe/liburing/issues/1553 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- include/linux/io_uring_types.h | 3 +++ io_uring/kbuf.c | 10 +++++++--- 2 files changed, 10 insertions(+), 3 deletions(-) --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -518,6 +518,7 @@ enum { REQ_F_BL_NO_RECYCLE_BIT, REQ_F_BUFFERS_COMMIT_BIT, REQ_F_BUF_NODE_BIT, + REQ_F_BUF_MORE_BIT, REQ_F_HAS_METADATA_BIT, REQ_F_IMPORT_BUFFER_BIT, REQ_F_SQE_COPIED_BIT, @@ -603,6 +604,8 @@ enum { REQ_F_BUFFERS_COMMIT = IO_REQ_FLAG(REQ_F_BUFFERS_COMMIT_BIT), /* buf node is valid */ REQ_F_BUF_NODE = IO_REQ_FLAG(REQ_F_BUF_NODE_BIT), + /* incremental buffer consumption, more space available */ + REQ_F_BUF_MORE = IO_REQ_FLAG(REQ_F_BUF_MORE_BIT), /* request has read/write metadata assigned */ REQ_F_HAS_METADATA = IO_REQ_FLAG(REQ_F_HAS_METADATA_BIT), /* --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -216,7 +216,8 @@ static struct io_br_sel io_ring_buffer_s sel.addr = u64_to_user_ptr(READ_ONCE(buf->addr)); if (io_should_commit(req, issue_flags)) { - io_kbuf_commit(req, sel.buf_list, *len, 1); + if (!io_kbuf_commit(req, sel.buf_list, *len, 1)) + req->flags |= REQ_F_BUF_MORE; sel.buf_list = NULL; } return sel; @@ -349,7 +350,8 @@ int io_buffers_select(struct io_kiocb *r */ if (ret > 0) { req->flags |= REQ_F_BUFFERS_COMMIT | REQ_F_BL_NO_RECYCLE; - io_kbuf_commit(req, sel->buf_list, arg->out_len, ret); + if (!io_kbuf_commit(req, sel->buf_list, arg->out_len, ret)) + req->flags |= REQ_F_BUF_MORE; } } else { ret = io_provided_buffers_select(req, &arg->out_len, sel->buf_list, arg->iovs); @@ -395,8 +397,10 @@ static inline bool __io_put_kbuf_ring(st if (bl) ret = io_kbuf_commit(req, bl, len, nr); + if (ret && (req->flags & REQ_F_BUF_MORE)) + ret = false; - req->flags &= ~REQ_F_BUFFER_RING; + req->flags &= ~(REQ_F_BUFFER_RING | REQ_F_BUF_MORE); return ret; }