From 28856ab2c0b5b6e87b9a9739a0b59b6ff83689bd Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 12 Oct 2023 04:13:58 -0700 Subject: [PATCH 1/4] netconsole: move init/cleanup functions lower Move alloc_param_target() and its counterpart (free_param_target()) to the bottom of the file. These functions are called mostly at initialization/cleanup of the module, and they should be just above the callers, at the bottom of the file. From a practical perspective, having alloc_param_target() at the bottom of the file will avoid forward declaration later (in the following patch). Nothing changed other than the functions location. Suggested-by: Jakub Kicinski Signed-off-by: Breno Leitao Link: https://lore.kernel.org/r/20231012111401.333798-2-leitao@debian.org Signed-off-by: Jakub Kicinski --- drivers/net/netconsole.c | 104 +++++++++++++++++++-------------------- 1 file changed, 52 insertions(+), 52 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 3111e1648592..d609fb59cf99 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -192,58 +192,6 @@ static struct netconsole_target *alloc_and_init(void) return nt; } -/* Allocate new target (from boot/module param) and setup netpoll for it */ -static struct netconsole_target *alloc_param_target(char *target_config) -{ - struct netconsole_target *nt; - int err; - - nt = alloc_and_init(); - if (!nt) { - err = -ENOMEM; - goto fail; - } - - if (*target_config == '+') { - nt->extended = true; - target_config++; - } - - if (*target_config == 'r') { - if (!nt->extended) { - pr_err("Netconsole configuration error. Release feature requires extended log message"); - err = -EINVAL; - goto fail; - } - nt->release = true; - target_config++; - } - - /* Parse parameters and setup netpoll */ - err = netpoll_parse_options(&nt->np, target_config); - if (err) - goto fail; - - err = netpoll_setup(&nt->np); - if (err) - goto fail; - - nt->enabled = true; - - return nt; - -fail: - kfree(nt); - return ERR_PTR(err); -} - -/* Cleanup netpoll for given target (from boot/module param) and free it */ -static void free_param_target(struct netconsole_target *nt) -{ - netpoll_cleanup(&nt->np); - kfree(nt); -} - #ifdef CONFIG_NETCONSOLE_DYNAMIC /* @@ -938,6 +886,58 @@ static void write_msg(struct console *con, const char *msg, unsigned int len) spin_unlock_irqrestore(&target_list_lock, flags); } +/* Allocate new target (from boot/module param) and setup netpoll for it */ +static struct netconsole_target *alloc_param_target(char *target_config) +{ + struct netconsole_target *nt; + int err; + + nt = alloc_and_init(); + if (!nt) { + err = -ENOMEM; + goto fail; + } + + if (*target_config == '+') { + nt->extended = true; + target_config++; + } + + if (*target_config == 'r') { + if (!nt->extended) { + pr_err("Netconsole configuration error. Release feature requires extended log message"); + err = -EINVAL; + goto fail; + } + nt->release = true; + target_config++; + } + + /* Parse parameters and setup netpoll */ + err = netpoll_parse_options(&nt->np, target_config); + if (err) + goto fail; + + err = netpoll_setup(&nt->np); + if (err) + goto fail; + + nt->enabled = true; + + return nt; + +fail: + kfree(nt); + return ERR_PTR(err); +} + +/* Cleanup netpoll for given target (from boot/module param) and free it */ +static void free_param_target(struct netconsole_target *nt) +{ + netpoll_cleanup(&nt->np); + kfree(nt); +} + static struct console netconsole_ext = { .name = "netcon_ext", .flags = CON_ENABLED | CON_EXTENDED, From 131eeb45b96107b19f9f231d6e81348b471b2ed0 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 12 Oct 2023 04:13:59 -0700 Subject: [PATCH 2/4] netconsole: Initialize configfs_item for default targets For netconsole targets allocated during the boot time (passing netconsole=... argument), netconsole_target->item is not initialized. That is not a problem because it is not used inside configfs. An upcoming patch will be using it, thus, initialize the targets with the name 'cmdline' plus a counter starting from 0. This name will match entries in the configfs later. Suggested-by: Joel Becker Signed-off-by: Breno Leitao Link: https://lore.kernel.org/r/20231012111401.333798-3-leitao@debian.org Signed-off-by: Jakub Kicinski --- drivers/net/netconsole.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index d609fb59cf99..e153bce4dee4 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -53,6 +53,8 @@ static bool oops_only = false; module_param(oops_only, bool, 0600); MODULE_PARM_DESC(oops_only, "Only log oops messages"); +#define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline" + #ifndef MODULE static int __init option_setup(char *opt) { @@ -165,6 +167,10 @@ static void netconsole_target_put(struct netconsole_target *nt) { } +static void populate_configfs_item(struct netconsole_target *nt, + int cmdline_count) +{ +} #endif /* CONFIG_NETCONSOLE_DYNAMIC */ /* Allocate and initialize with defaults. @@ -688,6 +694,17 @@ static struct configfs_subsystem netconsole_subsys = { }, }; +static void populate_configfs_item(struct netconsole_target *nt, + int cmdline_count) +{ + char target_name[16]; + + snprintf(target_name, sizeof(target_name), "%s%d", + NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count); + config_item_init_type_name(&nt->item, target_name, + &netconsole_target_type); +} + #endif /* CONFIG_NETCONSOLE_DYNAMIC */ /* Handle network interface device notifications */ @@ -887,7 +904,8 @@ static void write_msg(struct console *con, const char *msg, unsigned int len) } /* Allocate new target (from boot/module param) and setup netpoll for it */ -static struct netconsole_target *alloc_param_target(char *target_config) +static struct netconsole_target *alloc_param_target(char *target_config, + int cmdline_count) { struct netconsole_target *nt; int err; @@ -922,6 +940,7 @@ static struct netconsole_target *alloc_param_target(char *target_config) if (err) goto fail; + populate_configfs_item(nt, cmdline_count); nt->enabled = true; return nt; @@ -954,6 +973,7 @@ static int __init init_netconsole(void) { int err; struct netconsole_target *nt, *tmp; + unsigned int count = 0; bool extended = false; unsigned long flags; char *target_config; @@ -961,7 +981,7 @@ static int __init init_netconsole(void) if (strnlen(input, MAX_PARAM_LENGTH)) { while ((target_config = strsep(&input, ";"))) { - nt = alloc_param_target(target_config); + nt = alloc_param_target(target_config, count); if (IS_ERR(nt)) { err = PTR_ERR(nt); goto fail; @@ -977,6 +997,7 @@ static int __init init_netconsole(void) spin_lock_irqsave(&target_list_lock, flags); list_add(&nt->list, &target_list); spin_unlock_irqrestore(&target_list_lock, flags); + count++; } } From 5fbd6cdbe304b4154f63e3f8abf7c9c644ccb62c Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 12 Oct 2023 04:14:00 -0700 Subject: [PATCH 3/4] netconsole: Attach cmdline target to dynamic target Enable the attachment of a dynamic target to the target created during boot time. The boot-time targets are named as "cmdline\d", where "\d" is a number starting at 0. If the user creates a dynamic target named "cmdline0", it will attach to the first target created at boot time (as defined in the `netconsole=...` command line argument). `cmdline1` will attach to the second target and so forth. If there is no netconsole target created at boot time, then, the target name could be reused. Relevant design discussion: https://lore.kernel.org/all/ZRWRal5bW93px4km@gmail.com/ Suggested-by: Joel Becker Signed-off-by: Breno Leitao Link: https://lore.kernel.org/r/20231012111401.333798-4-leitao@debian.org Signed-off-by: Jakub Kicinski --- drivers/net/netconsole.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index e153bce4dee4..6e14ba5e06c8 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -629,6 +629,23 @@ static const struct config_item_type netconsole_target_type = { .ct_owner = THIS_MODULE, }; +static struct netconsole_target *find_cmdline_target(const char *name) +{ + struct netconsole_target *nt, *ret = NULL; + unsigned long flags; + + spin_lock_irqsave(&target_list_lock, flags); + list_for_each_entry(nt, &target_list, list) { + if (!strcmp(nt->item.ci_name, name)) { + ret = nt; + break; + } + } + spin_unlock_irqrestore(&target_list_lock, flags); + + return ret; +} + /* * Group operations and type for netconsole_subsys. */ @@ -639,6 +656,17 @@ static struct config_item *make_netconsole_target(struct config_group *group, struct netconsole_target *nt; unsigned long flags; + /* Checking if a target by this name was created at boot time. If so, + * attach a configfs entry to that target. This enables dynamic + * control. + */ + if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX, + strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) { + nt = find_cmdline_target(name); + if (nt) + return &nt->item; + } + nt = alloc_and_init(); if (!nt) return ERR_PTR(-ENOMEM); From 7eeb84d89f2e561ac5b97e0142c029908ddf00d5 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 12 Oct 2023 04:14:01 -0700 Subject: [PATCH 4/4] Documentation: netconsole: add support for cmdline targets With the previous patches, there is no more limitation at modifying the targets created at boot time (or module load time). Document the way on how to create the configfs directories to be able to modify these netconsole targets. The design discussion about this topic could be found at: https://lore.kernel.org/all/ZRWRal5bW93px4km@gmail.com/ Signed-off-by: Breno Leitao Link: https://lore.kernel.org/r/20231012111401.333798-5-leitao@debian.org Signed-off-by: Jakub Kicinski --- Documentation/networking/netconsole.rst | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst index 7a9de0568e84..390730a74332 100644 --- a/Documentation/networking/netconsole.rst +++ b/Documentation/networking/netconsole.rst @@ -99,9 +99,6 @@ Dynamic reconfiguration: Dynamic reconfigurability is a useful addition to netconsole that enables remote logging targets to be dynamically added, removed, or have their parameters reconfigured at runtime from a configfs-based userspace interface. -[ Note that the parameters of netconsole targets that were specified/created -from the boot/module option are not exposed via this interface, and hence -cannot be modified dynamically. ] To include this feature, select CONFIG_NETCONSOLE_DYNAMIC when building the netconsole module (or kernel, if netconsole is built-in). @@ -155,6 +152,25 @@ You can also update the local interface dynamically. This is especially useful if you want to use interfaces that have newly come up (and may not have existed when netconsole was loaded / initialized). +Netconsole targets defined at boot time (or module load time) with the +`netconsole=` param are assigned the name `cmdline`. For example, the +first target in the parameter is named `cmdline0`. You can control and modify +these targets by creating configfs directories with the matching name. + +Let's suppose you have two netconsole targets defined at boot time:: + + netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc;4444@10.0.0.1/eth1,9353@10.0.0.3/12:34:56:78:9a:bc + +You can modify these targets in runtime by creating the following targets:: + + mkdir cmdline0 + cat cmdline0/remote_ip + 10.0.0.2 + + mkdir cmdline1 + cat cmdline1/remote_ip + 10.0.0.3 + Extended console: =================