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path: root/drivers/net/netconsole.c
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2007-10-10[NET] netconsole: Support dynamic reconfiguration using configfsSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Support multiple logging targetsSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for multiple targets, independent of CONFIG_NETCONSOLE_DYNAMIC -- this is useful even in the default case and (including the infrastructure introduced in previous patches) doesn't really add too many bytes to module text. All the complexity (and size) comes with the dynamic reconfigurability / userspace interface patch, and so it's plausible users may want to keep this enabled but that disabled (say to avoid a dependency on CONFIG_CONFIGFS_FS too). Also update documentation to mention the use of ";" separator to specify multiple logging targets in the boot/module option string. Brief overview: We maintain a target_list (and corresponding lock). Get rid of the static "default_target" and introduce allocation and release functions for our netconsole_target objects (but keeping sure to preserve previous behaviour such as default values). During init_netconsole(), ";" is used as the separator to identify multiple target specifications in the boot/module option string. The target specifications are parsed and netpolls setup. During exit, the target_list is torn down and all items released. Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Introduce netconsole_netdev_notifierSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. To update fields of underlying netpoll structure at runtime on corresponding NETDEV_CHANGEADDR or NETDEV_CHANGENAME notifications. ioctl(SIOCSIFHWADDR or SIOCSIFNAME) could be used to change the hardware/MAC address or name of the local interface that our netpoll is attached to. Whenever this happens, netdev notifier chain is called out with the NETDEV_CHANGEADDR or NETDEV_CHANGENAME event message. We respond to that and update the local_mac or dev_name field of the struct netpoll. This makes sense anyway, but is especially required for dynamic netconsole because the netpoll structure's internal members become user visible files when either sysfs or configfs are used. So this helps us to keep up with the MAC address/name changes and keep values in struct netpoll uptodate. [ Note that ioctl(SIOCSIFADDR) to change IP address of interface at runtime is not handled (to update local_ip of netpoll) on purpose -- some setups may set the local_ip to a private address, not necessary the actual IP address of the sender host, as presently allowed. ] Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Introduce netconsole_targetSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. Introduce a wrapper structure over netpoll to represent logging targets configured in netconsole. This will get extended with other members in further patches. This is done independent of the (to-be-introduced) NETCONSOLE_DYNAMIC config option so that we're able to drastically cut down on the #ifdef complexity of final netconsole.c. Also, struct netconsole_target would be required for multiple targets support also, and not just dynamic reconfigurability. Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Use netif_running() in write_msg()Satyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. Avoid unnecessarily disabling interrupts and calling netpoll_send_udp() if the corresponding local interface is not up. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Simplify boot/module option setup logicSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. Presently, boot/module parameters are set up quite differently for the case of built-in netconsole (__setup() -> obsolete_checksetup() -> netpoll_parse_options() -> strlen(config) == 0 in init_netconsole()) vs modular netconsole (module_param_string() -> string copied to the config variable -> strlen(config) != 0 init_netconsole() -> netpoll_parse_options()). This patch makes both of them similar by doing exactly the equivalent of a module_param_string() in option_setup() also -- just copying the param string passed from the kernel command line into "config" variable. So, strlen(config) != 0 in both cases, and netpoll_parse_options() is always called from init_netconsole(), thus making the setup logic for both cases similar. Now, option_setup() is only ever called / used for the built-in case, so we put it inside a #ifndef MODULE, otherwise gcc will complain about option_setup() being "defined but not used". Also, the "configured" variable is redundant with this patch and hence removed. Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Remove bogus checkSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. The (!np.dev) check in write_msg() is bogus (always false), because: np.dev is set by netpoll_setup(), which is called by init_netconsole() before register_console(), so write_msg() cannot be triggered unless netpoll_setup() successfully set np.dev. Also np.dev cannot go away from under us, because netpoll_setup() grabs us reference on it. So let's remove the bogus check. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET] netconsole: Cleanups, codingstyle, prettyficationSatyam Sharma
Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. (1) Remove unwanted headers. (2) Mark __init and __exit as appropriate. (3) Various trivial codingstyle and prettification stuff. Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02netpoll queue cleanupStephen Hemminger
The beast had a long and not very happy history. At one point, a friend (netdump) had asked that he open up a little. Well, the friend was long gone now, and the beast had this dangling piece hanging (netpoll_queue). It wasn't hard to stitch the netpoll_queue back in where it belonged and make everything tidy. Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
2006-12-02netpoll setup error handlingStephen Hemminger
The beast was not always healthy. When it was sick, it tended to be laconic and not tell anyone the real problem. A few small changes had it telling the world about its problems, if they really wanted to hear. Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
2006-06-05[NETCONSOLE]: Clean up initcall warning.Matt Mackall
From: Matt Mackall <mpm@selenic.com> netconsole is being wrong here. If it wasn't enabled there's no error. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-09[NET] netconsole: set .name in struct consoleRandy Dunlap
Set .name in netconsole's struct console to identify the struct's owner. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-31[PATCH] Don't pass boot parameters to argv_init[]OGAWA Hirofumi
The boot cmdline is parsed in parse_early_param() and parse_args(,unknown_bootoption). And __setup() is used in obsolete_checksetup(). start_kernel() -> parse_args() -> unknown_bootoption() -> obsolete_checksetup() If __setup()'s callback (->setup_func()) returns 1 in obsolete_checksetup(), obsolete_checksetup() thinks a parameter was handled. If ->setup_func() returns 0, obsolete_checksetup() tries other ->setup_func(). If all ->setup_func() that matched a parameter returns 0, a parameter is seted to argv_init[]. Then, when runing /sbin/init or init=app, argv_init[] is passed to the app. If the app doesn't ignore those arguments, it will warning and exit. This patch fixes a wrong usage of it, however fixes obvious one only. Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!