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 B0AB8156E5 for ; Wed, 20 Sep 2023 12:36:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 307BBC433CD; Wed, 20 Sep 2023 12:36:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695213392; bh=FNglxMDhYr7sQn10Q8KCUkaHePNLtieMEZZYKOZFTOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eVX3i6wQyo/MIiKBibx7mbuf4AEZnqo1PBqnC1nIfaAnm6p03TiMqLM5I5pQ6/4Ua Apxij6DCXJzoGu2Z8+mdxDHyzPIB0EPjks5gKRMP3tJG/0GxRLr7PbmJZ9QMOBZD3A +qwpf/SpCkRxIy9pBO/jsOqa7IIhDQHxwDBg2wd0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Logan Gunthorpe , renlonglong , Dave Jiang , Jon Mason Subject: [PATCH 5.4 221/367] ntb: Fix calculation ntb_transport_tx_free_entry() Date: Wed, 20 Sep 2023 13:29:58 +0200 Message-ID: <20230920112904.314486390@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112858.471730572@linuxfoundation.org> References: <20230920112858.471730572@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Jiang commit 5a7693e6bbf19b22fd6c1d2c4b7beb0a03969e2c upstream. ntb_transport_tx_free_entry() never returns 0 with the current calculation. If head == tail, then it would return qp->tx_max_entry. Change compare to tail >= head and when they are equal, a 0 would be returned. Fixes: e74bfeedad08 ("NTB: Add flow control to the ntb_netdev") Reviewed-by: Logan Gunthorpe Signed-off-by: renlonglong Signed-off-by: Dave Jiang Signed-off-by: Jon Mason Signed-off-by: Greg Kroah-Hartman --- drivers/ntb/ntb_transport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/ntb/ntb_transport.c +++ b/drivers/ntb/ntb_transport.c @@ -2431,7 +2431,7 @@ unsigned int ntb_transport_tx_free_entry unsigned int head = qp->tx_index; unsigned int tail = qp->remote_rx_info->entry; - return tail > head ? tail - head : qp->tx_max_entry + tail - head; + return tail >= head ? tail - head : qp->tx_max_entry + tail - head; } EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);