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* [NET] netconsole: Support dynamic reconfiguration using configfsSatyam Sharma2007-10-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [NET]: Make NAPI polling independent of struct net_device objects.Stephen Hemminger2007-10-101-14/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Several devices have multiple independant RX queues per net device, and some have a single interrupt doorbell for several queues. In either case, it's easier to support layouts like that if the structure representing the poll is independant from the net device itself. The signature of the ->poll() call back goes from: int foo_poll(struct net_device *dev, int *budget) to int foo_poll(struct napi_struct *napi, int budget) The caller is returned the number of RX packets processed (or the number of "NAPI credits" consumed if you want to get abstract). The callee no longer messes around bumping dev->quota, *budget, etc. because that is all handled in the caller upon return. The napi_struct is to be embedded in the device driver private data structures. Furthermore, it is the driver's responsibility to disable all NAPI instances in it's ->stop() device close handler. Since the napi_struct is privatized into the driver's private data structures, only the driver knows how to get at all of the napi_struct instances it may have per-device. With lots of help and suggestions from Rusty Russell, Roland Dreier, Michael Chan, Jeff Garzik, and Jamal Hadi Salim. Bug fixes from Thomas Graf, Roland Dreier, Peter Zijlstra, Joseph Fannin, Scott Wood, Hans J. Koch, and Michael Chan. [ Ported to current tree and all drivers converted. Integrated Stephen's follow-on kerneldoc additions, and restored poll_list handling to the old style to fix mutual exclusion issues. -DaveM ] Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* WorkQueue: Fix up arch-specific work items where possibleDavid Howells2006-12-051-1/+1
| | | | | | | | | | Fix up arch-specific work items where possible to use the new work_struct and delayed_work structs. Three places that enqueue bits of their stack and then return have been marked with #error as this is not permitted. Signed-Off-By: David Howells <dhowells@redhat.com>
* netpoll header cleanupStephen Hemminger2006-12-021-4/+3
| | | | | | | | As Steve left netpoll beast, hopefully not to return soon. He noticed that the header was messy. He straightened it up and polished it a little, then waved goodbye. Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
* netpoll queue cleanupStephen Hemminger2006-12-021-2/+2
| | | | | | | | | | | | 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>
* netpoll retry cleanupStephen Hemminger2006-12-021-1/+0
| | | | | | | | | | | | The netpoll beast was still not happy. If the beast got clogged pipes, it tended to stare blankly off in space for a long time. The problem couldn't be completely fixed because the beast talked with irq's disabled. But it could be made less painful and shorter. Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
* netpoll per device txqStephen Hemminger2006-12-021-0/+2
| | | | | | | | | When the netpoll beast got really busy, it tended to clog things, so it stored them for later. But the beast was putting all it's skb's in one basket. This was bad because maybe some pipes were clogged and others were not. Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
* netpoll info leakStephen Hemminger2006-12-021-0/+1
| | | | | | | | | | | | | After looking harder, Steve noticed that the netpoll beast leaked a little every time it shutdown for a nap. Not a big leak, but a nuisance kind of thing. He took out his refcount duct tape and patched the leak. It was overkill since there was already other locking in that area, but it looked clean and wouldn't attract fleas. Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
* [NET] netpoll: break recursive loop in netpoll rx pathNeil Horman2006-06-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The netpoll system currently has a rx to tx path via: netpoll_rx __netpoll_rx arp_reply netpoll_send_skb dev->hard_start_tx This rx->tx loop places network drivers at risk of inadvertently causing a deadlock or BUG halt by recursively trying to acquire a spinlock that is used in both their rx and tx paths (this problem was origionally reported to me in the 3c59x driver, which shares a spinlock between the boomerang_interrupt and boomerang_start_xmit routines). This patch breaks this loop, by queueing arp frames, so that they can be responded to after all receive operations have been completed. Tested by myself and the reported with successful results. Specifically it was tested with netdump. Heres the BZ with details: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=194055 Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETPOLL]: wrong return for null netpoll_poll_lock()Ben Dooks2005-10-121-1/+1
| | | | | | | | | | When netpoll is not being used, the macro that defines the removed routing netpoll_poll_lock defines the return as zero, but the real routine returns a `void *` Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETPOLL]: fix initialization/NAPI raceMatt Mackall2005-08-111-6/+13
| | | | | | | | | | | This fixes a race during initialization with the NAPI softirq processing by using an RCU approach. This race was discovered when refill_skbs() was added to the setup code. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETPOLL]: add retry timeoutMatt Mackall2005-08-111-0/+1
| | | | | | | | | | | | | | Add limited retry logic to netpoll_send_skb Each time we attempt to send, decrement our per-device retry counter. On every successful send, we reset the counter. We delay 50us between attempts with up to 20000 retries for a total of 1 second. After we've exhausted our retries, subsequent failed attempts will try only once until reset by success. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETPOLL]: allow multiple netpoll_clients to register against one interfaceJeff Moyer2005-06-221-3/+12
| | | | | | | | | | | | | | | | | | | | This patch provides support for registering multiple netpoll clients to the same network device. Only one of these clients may register an rx_hook, however. In practice, this restriction has not been problematic. It is worth mentioning, though, that the current design can be easily extended to allow for the registration of multiple rx_hooks. The basic idea of the patch is that the rx_np pointer in the netpoll_info structure points to the struct netpoll that has rx_hook filled in. Aside from this one case, there is no need for a pointer from the struct net_device to an individual struct netpoll. A lock is introduced to protect the setting and clearing of the np_rx pointer. The pointer will only be cleared upon netpoll client module removal, and the lock should be uncontested. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETPOLL]: Introduce a netpoll_info structJeff Moyer2005-06-221-8/+17
| | | | | | | | | | | | | | | This patch introduces a netpoll_info structure, which the struct net_device will now point to instead of pointing to a struct netpoll. The reason for this is two-fold: 1) fields such as the rx_flags, poll_owner, and poll_lock should be maintained per net_device, not per netpoll; and 2) this is a first step in providing support for multiple netpoll clients to register against the same net_device. The struct netpoll is now pointed to by the netpoll_info structure. As such, the previous behaviour of the code is preserved. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETPOLL]: Set poll_owner to -1 before unlocking in netpoll_poll_unlock()Jeff Moyer2005-06-221-1/+1
| | | | | | | | This trivial patch moves the assignment of poll_owner to -1 inside of the lock. This fixes a potential SMP race in the code. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+67
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!
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