Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754923Ab0KHUcU (ORCPT ); Mon, 8 Nov 2010 15:32:20 -0500 Received: from smtp-out.google.com ([74.125.121.35]:2738 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754772Ab0KHUcS (ORCPT ); Mon, 8 Nov 2010 15:32:18 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=subject:to:from:cc:date:message-id:in-reply-to:references: user-agent:mime-version:content-type: content-transfer-encoding:x-system-of-record; b=WXdqt7knvzaCDsuTn/smrLxtI455gOOHr6+Ot96wJQJf1e+d+kaB2QaS7V88Ej/EP wi90FZ/jHKymlqSXGtxFg== Subject: [PATCH v2 02/23] netconsole: Introduce locking over the netpoll fields To: simon.kagstrom@netinsight.net, davem@davemloft.net, nhorman@tuxdriver.com, Matt Mackall From: Mike Waychison Cc: adurbin@google.com, linux-kernel@vger.kernel.org, chavey@google.com, Greg KH , =?utf-8?q?Am=C3=A9rico?= Wang , akpm@linux-foundation.org, linux-api@vger.kernel.org Date: Mon, 08 Nov 2010 12:31:48 -0800 Message-ID: <20101108203147.22479.8515.stgit@crlf.mtv.corp.google.com> In-Reply-To: <20101108203120.22479.19708.stgit@crlf.mtv.corp.google.com> References: <20101108203120.22479.19708.stgit@crlf.mtv.corp.google.com> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6982 Lines: 221 The netconsole driver currently doesn't do any locking over its configuration fields. This can cause problems if we were to ever have concurrent writing to fields while somebody is enabling the service. For simplicity, this patch extends targets_list_lock to cover all configuration fields within the targets. Macros are also added here to wrap accessors so that we check whether the target has been enabled with locking handled. Signed-off-by: Mike Waychison --- drivers/net/netconsole.c | 114 ++++++++++++++++++++++++++-------------------- 1 files changed, 64 insertions(+), 50 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index c87a49e..6e16888 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -327,6 +327,7 @@ static ssize_t store_enabled(struct netconsole_target *nt, const char *buf, size_t count) { + unsigned long flags; int err; long enabled; @@ -335,6 +336,10 @@ static ssize_t store_enabled(struct netconsole_target *nt, return enabled; if (enabled) { /* 1 */ + spin_lock_irqsave(&target_list_lock, flags); + if (nt->enabled) + goto busy; + spin_unlock_irqrestore(&target_list_lock, flags); /* * Skip netpoll_parse_options() -- all the attributes are @@ -343,18 +348,28 @@ static ssize_t store_enabled(struct netconsole_target *nt, netpoll_print_options(&nt->np); err = netpoll_setup(&nt->np); + spin_lock_irqsave(&target_list_lock, flags); + if (err) + nt->enabled = 0; + else + nt->enabled = 1; + spin_unlock_irqrestore(&target_list_lock, flags); if (err) return err; printk(KERN_INFO "netconsole: network logging started\n"); - } else { /* 0 */ + spin_lock_irqsave(&target_list_lock, flags); + nt->enabled = 0; + spin_unlock_irqrestore(&target_list_lock, flags); + netpoll_cleanup(&nt->np); } - nt->enabled = enabled; - return strnlen(buf, count); +busy: + spin_unlock_irqrestore(&target_list_lock, flags); + return -EBUSY; } static ssize_t store_dev_name(struct netconsole_target *nt, @@ -363,13 +378,6 @@ static ssize_t store_dev_name(struct netconsole_target *nt, { size_t len; - if (nt->enabled) { - printk(KERN_ERR "netconsole: target (%s) is enabled, " - "disable to update parameters\n", - config_item_name(&nt->item)); - return -EINVAL; - } - strlcpy(nt->np.dev_name, buf, IFNAMSIZ); /* Get rid of possible trailing newline from echo(1) */ @@ -387,13 +395,6 @@ static ssize_t store_local_port(struct netconsole_target *nt, long local_port; #define __U16_MAX ((__u16) ~0U) - if (nt->enabled) { - printk(KERN_ERR "netconsole: target (%s) is enabled, " - "disable to update parameters\n", - config_item_name(&nt->item)); - return -EINVAL; - } - local_port = strtol10_check_range(buf, 0, __U16_MAX); if (local_port < 0) return local_port; @@ -410,13 +411,6 @@ static ssize_t store_remote_port(struct netconsole_target *nt, long remote_port; #define __U16_MAX ((__u16) ~0U) - if (nt->enabled) { - printk(KERN_ERR "netconsole: target (%s) is enabled, " - "disable to update parameters\n", - config_item_name(&nt->item)); - return -EINVAL; - } - remote_port = strtol10_check_range(buf, 0, __U16_MAX); if (remote_port < 0) return remote_port; @@ -430,13 +424,6 @@ static ssize_t store_local_ip(struct netconsole_target *nt, const char *buf, size_t count) { - if (nt->enabled) { - printk(KERN_ERR "netconsole: target (%s) is enabled, " - "disable to update parameters\n", - config_item_name(&nt->item)); - return -EINVAL; - } - nt->np.local_ip = in_aton(buf); return strnlen(buf, count); @@ -446,13 +433,6 @@ static ssize_t store_remote_ip(struct netconsole_target *nt, const char *buf, size_t count) { - if (nt->enabled) { - printk(KERN_ERR "netconsole: target (%s) is enabled, " - "disable to update parameters\n", - config_item_name(&nt->item)); - return -EINVAL; - } - nt->np.remote_ip = in_aton(buf); return strnlen(buf, count); @@ -466,13 +446,6 @@ static ssize_t store_remote_mac(struct netconsole_target *nt, char *p = (char *) buf; int i; - if (nt->enabled) { - printk(KERN_ERR "netconsole: target (%s) is enabled, " - "disable to update parameters\n", - config_item_name(&nt->item)); - return -EINVAL; - } - for (i = 0; i < ETH_ALEN - 1; i++) { remote_mac[i] = simple_strtoul(p, &p, 16); if (*p != ':') @@ -496,15 +469,56 @@ invalid: * Attribute definitions for netconsole_target. */ -#define NETCONSOLE_TARGET_ATTR_RO(_name) \ +#define __NETCONSOLE_TARGET_ATTR_RO(_name, _prefix_...) \ static struct netconsole_target_attr netconsole_target_##_name = \ - __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL) + __CONFIGFS_ATTR(_name, S_IRUGO, show_##_prefix_##_name, NULL) -#define NETCONSOLE_TARGET_ATTR_RW(_name) \ +#define __NETCONSOLE_TARGET_ATTR_RW(_name, _prefix_...) \ static struct netconsole_target_attr netconsole_target_##_name = \ - __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name) + __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, \ + show_##_prefix_##_name, store_##_prefix_##_name) + +#define NETCONSOLE_WRAP_ATTR_STORE(_name) \ +static ssize_t store_locked_##_name(struct netconsole_target *nt, \ + const char *buf, \ + size_t count) \ +{ \ + unsigned long flags; \ + ssize_t ret; \ + spin_lock_irqsave(&target_list_lock, flags); \ + if (nt->enabled) { \ + printk(KERN_ERR "netconsole: target (%s) is enabled, " \ + "disable to update parameters\n", \ + config_item_name(&nt->item)); \ + spin_unlock_irqrestore(&target_list_lock, flags); \ + return -EBUSY; \ + } \ + ret = store_##_name(nt, buf, count); \ + spin_unlock_irqrestore(&target_list_lock, flags); \ + return ret; \ +} + +#define NETCONSOLE_WRAP_ATTR_SHOW(_name) \ +static ssize_t show_locked_##_name(struct netconsole_target *nt, char *buf) \ +{ \ + unsigned long flags; \ + ssize_t ret; \ + spin_lock_irqsave(&target_list_lock, flags); \ + ret = show_##_name(nt, buf); \ + spin_unlock_irqrestore(&target_list_lock, flags); \ + return ret; \ +} + +#define NETCONSOLE_TARGET_ATTR_RW(_name) \ + NETCONSOLE_WRAP_ATTR_STORE(_name) \ + NETCONSOLE_WRAP_ATTR_SHOW(_name) \ + __NETCONSOLE_TARGET_ATTR_RW(_name, locked_) + +#define NETCONSOLE_TARGET_ATTR_RO(_name) \ + NETCONSOLE_WRAP_ATTR_SHOW(_name) \ + __NETCONSOLE_TARGET_ATTR_RO(_name, locked_) -NETCONSOLE_TARGET_ATTR_RW(enabled); +__NETCONSOLE_TARGET_ATTR_RW(enabled); NETCONSOLE_TARGET_ATTR_RW(dev_name); NETCONSOLE_TARGET_ATTR_RW(local_port); NETCONSOLE_TARGET_ATTR_RW(remote_port); -- 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/