From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: [PATCH 2/8] n_gsm: uplink SKBs accumulate on list Date: Mon, 13 Aug 2012 13:43:36 +0100 Message-ID: <20120813124326.6125.86930.stgit@localhost.localdomain> References: <20120813124254.6125.70371.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:43373 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665Ab2HMM0Q (ORCPT ); Mon, 13 Aug 2012 08:26:16 -0400 In-Reply-To: <20120813124254.6125.70371.stgit@localhost.localdomain> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: greg@kroah.com, linux-serial@vger.kernel.org From: Russ Gorby gsm_dlci_data_kick will not call any output function if tx_bytes > THRESH_LO furthermore it will call the output function only once if tx_bytes == 0 If the size of the IP writes are on the order of THRESH_LO we can get into a situation where skbs accumulate on the outbound list being starved for events to call the output function. gsm_dlci_data_kick now calls the sweep function when tx_bytes==0 Signed-off-by: Russ Gorby Tested-by: Kappel, LaurentX Signed-off-by: Alan Cox Cc: Hay and Water --- drivers/tty/n_gsm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 5c6c2e2..9b0a44d 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -971,16 +971,19 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm) static void gsm_dlci_data_kick(struct gsm_dlci *dlci) { unsigned long flags; + int sweep; spin_lock_irqsave(&dlci->gsm->tx_lock, flags); /* If we have nothing running then we need to fire up */ + sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); if (dlci->gsm->tx_bytes == 0) { if (dlci->net) gsm_dlci_data_output_framed(dlci->gsm, dlci); else gsm_dlci_data_output(dlci->gsm, dlci); - } else if (dlci->gsm->tx_bytes < TX_THRESH_LO) - gsm_dlci_data_sweep(dlci->gsm); + } + if (sweep) + gsm_dlci_data_sweep(dlci->gsm); spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); }