From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756556AbbJ2JQy (ORCPT ); Thu, 29 Oct 2015 05:16:54 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:33174 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750927AbbJ2JQv (ORCPT ); Thu, 29 Oct 2015 05:16:51 -0400 From: Saurabh Sengar To: jdike@addtoit.com, richard@nod.at, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-kernel@vger.kernel.org Cc: Saurabh Sengar Subject: [PATCH v3] um: net: replace GFP_KERNEL with GFP_ATOMIC when spinlock is held Date: Thu, 29 Oct 2015 14:46:43 +0530 Message-Id: <1446110203-21968-1-git-send-email-saurabh.truth@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org replace GFP_KERNEL with GFP_ATOMIC while spinlock is held, as code while holding a spinlock should be atomic. GFP_KERNEL may sleep and can cause deadlock, where as GFP_ATOMIC may fail but certainly avoids deadlock Signed-off-by: Saurabh Sengar --- v3: removed the atomic variable, as per Richard comment arch/um/drivers/net_kern.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c index f70dd54..d898f6c 100644 --- a/arch/um/drivers/net_kern.c +++ b/arch/um/drivers/net_kern.c @@ -388,7 +388,7 @@ static const struct net_device_ops uml_netdev_ops = { static int driver_registered; static void eth_configure(int n, void *init, char *mac, - struct transport *transport) + struct transport *transport, int gfp_mask) { struct uml_net *device; struct net_device *dev; @@ -397,7 +397,7 @@ static void eth_configure(int n, void *init, char *mac, size = transport->private_size + sizeof(struct uml_net_private); - device = kzalloc(sizeof(*device), GFP_KERNEL); + device = kzalloc(sizeof(*device), gfp_mask); if (device == NULL) { printk(KERN_ERR "eth_configure failed to allocate struct " "uml_net\n"); @@ -568,7 +568,7 @@ static LIST_HEAD(transports); static LIST_HEAD(eth_cmd_line); static int check_transport(struct transport *transport, char *eth, int n, - void **init_out, char **mac_out) + void **init_out, char **mac_out, int gfp_mask) { int len; @@ -582,7 +582,7 @@ static int check_transport(struct transport *transport, char *eth, int n, else if (*eth != '\0') return 0; - *init_out = kmalloc(transport->setup_size, GFP_KERNEL); + *init_out = kmalloc(transport->setup_size, gfp_mask); if (*init_out == NULL) return 1; @@ -600,20 +600,22 @@ void register_transport(struct transport *new) void *init; char *mac = NULL; int match; + int gfp_mask; spin_lock(&transports_lock); BUG_ON(!list_empty(&new->list)); list_add(&new->list, &transports); spin_unlock(&transports_lock); + gfp_mask = GFP_KERNEL; list_for_each_safe(ele, next, ð_cmd_line) { eth = list_entry(ele, struct eth_init, list); match = check_transport(new, eth->init, eth->index, &init, - &mac); + &mac, gfp_mask); if (!match) continue; else if (init != NULL) { - eth_configure(eth->index, init, mac, new); + eth_configure(eth->index, init, mac, new, gfp_mask); kfree(init); } list_del(ð->list); @@ -627,14 +629,17 @@ static int eth_setup_common(char *str, int index) void *init; char *mac = NULL; int found = 0; + int gfp_mask; spin_lock(&transports_lock); + gfp_mask = GFP_ATOMIC; list_for_each(ele, &transports) { transport = list_entry(ele, struct transport, list); - if (!check_transport(transport, str, index, &init, &mac)) + if (!check_transport(transport, str, index, &init, + &mac, gfp_mask)) continue; if (init != NULL) { - eth_configure(index, init, mac, transport); + eth_configure(index, init, mac, transport, gfp_mask); kfree(init); } found = 1; -- 1.9.1