Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757680Ab3HATfm (ORCPT ); Thu, 1 Aug 2013 15:35:42 -0400 Received: from usmamail.tilera.com ([12.216.194.151]:21419 "EHLO USMAMAIL.TILERA.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757624Ab3HATfh (ORCPT ); Thu, 1 Aug 2013 15:35:37 -0400 Message-ID: In-Reply-To: References: <20130801.113100.2059303096028571906.davem@davemloft.net> From: Chris Metcalf Date: Thu, 1 Aug 2013 11:36:42 -0400 Subject: [PATCH v3 07/13] tile: fix panic bug in napi support for tilegx network driver To: , MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3421 Lines: 109 The code used to call napi_disable() in an interrupt handler (from smp_call_function), which in turn could call msleep(). Unfortunately you can't sleep in an interrupt context. Luckily it turns out all the NAPI support functions are just operating on data structures and not on any deeply per-cpu data, so we can arrange to set up and tear down all the NAPI state on the core driving the process, and just do the IRQ enable/disable as a smp_call_function thing. Signed-off-by: Chris Metcalf --- drivers/net/ethernet/tile/tilegx.c | 65 +++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 32 deletions(-) diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c index e9eba2b..17bcf33 100644 --- a/drivers/net/ethernet/tile/tilegx.c +++ b/drivers/net/ethernet/tile/tilegx.c @@ -650,37 +650,13 @@ static enum hrtimer_restart tile_net_handle_egress_timer(struct hrtimer *t) return HRTIMER_NORESTART; } -/* Helper function for "tile_net_update()". - * "dev" (i.e. arg) is the device being brought up or down, - * or NULL if all devices are now down. - */ -static void tile_net_update_cpu(void *arg) +/* Helper function for "tile_net_update()". */ +static void manage_ingress_irq(void *enable) { - struct tile_net_info *info = &__get_cpu_var(per_cpu_info); - struct net_device *dev = arg; - - if (!info->has_iqueue) - return; - - if (dev != NULL) { - if (!info->napi_added) { - netif_napi_add(dev, &info->napi, - tile_net_poll, TILE_NET_WEIGHT); - info->napi_added = true; - } - if (!info->napi_enabled) { - napi_enable(&info->napi); - info->napi_enabled = true; - } + if (enable) enable_percpu_irq(ingress_irq, 0); - } else { + else disable_percpu_irq(ingress_irq); - if (info->napi_enabled) { - napi_disable(&info->napi); - info->napi_enabled = false; - } - /* FIXME: Drain the iqueue. */ - } } /* Helper function for tile_net_open() and tile_net_stop(). @@ -717,10 +693,35 @@ static int tile_net_update(struct net_device *dev) return -EIO; } - /* Update all cpus, sequentially (to protect "netif_napi_add()"). */ - for_each_online_cpu(cpu) - smp_call_function_single(cpu, tile_net_update_cpu, - (saw_channel ? dev : NULL), 1); + /* Update all cpus, sequentially (to protect "netif_napi_add()"). + * We use on_each_cpu to handle the IPI mask or unmask. + */ + if (!saw_channel) + on_each_cpu(manage_ingress_irq, (void *)0, 1); + for_each_online_cpu(cpu) { + struct tile_net_info *info = &per_cpu(per_cpu_info, cpu); + if (!info->has_iqueue) + continue; + if (saw_channel) { + if (!info->napi_added) { + netif_napi_add(dev, &info->napi, + tile_net_poll, TILE_NET_WEIGHT); + info->napi_added = true; + } + if (!info->napi_enabled) { + napi_enable(&info->napi); + info->napi_enabled = true; + } + } else { + if (info->napi_enabled) { + napi_disable(&info->napi); + info->napi_enabled = false; + } + /* FIXME: Drain the iqueue. */ + } + } + if (saw_channel) + on_each_cpu(manage_ingress_irq, (void *)1, 1); /* HACK: Allow packets to flow in the simulator. */ if (saw_channel) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/