From bea3348eef27e6044b6161fd04c3152215f96411 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Wed, 3 Oct 2007 16:41:36 -0700 Subject: [NET]: Make NAPI polling independent of struct net_device objects. 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 Signed-off-by: David S. Miller --- include/linux/netpoll.h | 55 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 41 insertions(+), 14 deletions(-) (limited to 'include/linux/netpoll.h') diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 29930b71a9aa..08dcc39ec18d 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -25,8 +25,6 @@ struct netpoll { struct netpoll_info { atomic_t refcnt; - spinlock_t poll_lock; - int poll_owner; int rx_flags; spinlock_t rx_lock; struct netpoll *rx_np; /* netpoll that registered an rx_hook */ @@ -64,32 +62,61 @@ static inline int netpoll_rx(struct sk_buff *skb) return ret; } -static inline void *netpoll_poll_lock(struct net_device *dev) +static inline int netpoll_receive_skb(struct sk_buff *skb) { + if (!list_empty(&skb->dev->napi_list)) + return netpoll_rx(skb); + return 0; +} + +static inline void *netpoll_poll_lock(struct napi_struct *napi) +{ + struct net_device *dev = napi->dev; + rcu_read_lock(); /* deal with race on ->npinfo */ - if (dev->npinfo) { - spin_lock(&dev->npinfo->poll_lock); - dev->npinfo->poll_owner = smp_processor_id(); - return dev->npinfo; + if (dev && dev->npinfo) { + spin_lock(&napi->poll_lock); + napi->poll_owner = smp_processor_id(); + return napi; } return NULL; } static inline void netpoll_poll_unlock(void *have) { - struct netpoll_info *npi = have; + struct napi_struct *napi = have; - if (npi) { - npi->poll_owner = -1; - spin_unlock(&npi->poll_lock); + if (napi) { + napi->poll_owner = -1; + spin_unlock(&napi->poll_lock); } rcu_read_unlock(); } +static inline void netpoll_netdev_init(struct net_device *dev) +{ + INIT_LIST_HEAD(&dev->napi_list); +} + #else -#define netpoll_rx(a) 0 -#define netpoll_poll_lock(a) NULL -#define netpoll_poll_unlock(a) +static inline int netpoll_rx(struct sk_buff *skb) +{ + return 0; +} +static inline int netpoll_receive_skb(struct sk_buff *skb) +{ + return 0; +} +static inline void *netpoll_poll_lock(struct napi_struct *napi) +{ + return NULL; +} +static inline void netpoll_poll_unlock(void *have) +{ +} +static inline void netpoll_netdev_init(struct net_device *dev) +{ +} #endif #endif -- cgit v1.2.3 From 0bcc1816188e570bde1d56a208996660f2633ae0 Mon Sep 17 00:00:00 2001 From: Satyam Sharma Date: Fri, 10 Aug 2007 15:35:05 -0700 Subject: [NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii . 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 Acked-by: Keiichi Kii Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- include/linux/netpoll.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/netpoll.h') diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 08dcc39ec18d..20250d963d72 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -35,6 +35,7 @@ struct netpoll_info { void netpoll_poll(struct netpoll *np); void netpoll_send_udp(struct netpoll *np, const char *msg, int len); +void netpoll_print_options(struct netpoll *np); int netpoll_parse_options(struct netpoll *np, char *opt); int netpoll_setup(struct netpoll *np); int netpoll_trap(void); -- cgit v1.2.3