src-test2/sys/dev/netmap/netmap.c, branch release/11.3.0

MFC r343579, r344253

2019-02-25T09:13:33Z

netmap: fix lock order reversal related to kqueue usage When using poll(), select() or kevent() on netmap file descriptors, netmap executes the equivalent of NIOCTXSYNC and NIOCRXSYNC commands, before collecting the events that are ready. In other words, the poll/kevent callback has side effects. This is done to avoid the overhead of two system call per iteration (e.g., poll() + ioctl(NIOC*XSYNC)). When the kqueue subsystem invokes the kqueue(9) f_event callback (netmap_knrw), it holds the lock of the struct knlist object associated to the netmap port (the lock is provided at initialization, by calling knlist_init_mtx). However, netmap_knrw() may need to wake up another netmap port (or even the same one), which means that it may need to call knote(). Since knote() needs the lock of the struct knlist object associated to the to-be-wake-up netmap port, it is possible to have a lock order reversal problem (AB/BA deadlock). This change prevents the deadlock by executing the knote() call in a per-selinfo taskqueue, where it is possible to hold a mutex. The change also adds a counter (kqueue_users) to keep track of how many kqueue users are referencing a given struct nm_selinfo. In this way, nm_os_selwakeup() can schedule the kevent notification task only when kqueue is actually being used. This is important to avoid wasting CPU in the common case where kqueue is not used. Reviewed by: aleksandr.fedorov_itglobal.com Differential Revision: https://reviews.freebsd.org/D18956

MFC r343772, r343867

2019-02-12T09:26:05Z

netmap: refactor logging macros and pipes Changelist: - Replace ND, D and RD macros with nm_prdis, nm_prinf, nm_prerr and nm_prlim, to avoid possible naming conflicts. - Add netmap_krings_mode_commit() helper function and use that to reduce code duplication. - Refactor pipes control code to export some functions that can be reused by the veth driver (on Linux) and epair(4). - Add check to reject API requests with version less than 11. - Small code refactoring for the null adapter.

MFC r343689

2019-02-07T10:44:53Z

netmap: upgrade sync-kloop support Add SYNC_KLOOP_MODE option, and add support for direct mode, where application executes the TXSYNC and RXSYNC in the context of the ioeventfd wake up callback.

MFC r343344

2019-02-06T09:38:44Z

netmap: fix knote() argument to match the mutex state The nm_os_selwakeup function needs to call knote() to wake up kqueue(9) users. However, this function can be called from different code paths, with different lock requirements. This patch fixes the knote() call argument to match the relavant lock state. Also, comments have been updated to reflect current code. PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219846 Reported by: Aleksandr Fedorov Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D18876

MFC r342368, r342369

2018-12-31T11:10:02Z

netmap: fix bug in netmap_poll() optimization The bug was introduced by r339639, although it is present in the upstream netmap code since 2015. It is due to resetting the want_rx variable to POLLIN, rather than resetting it to POLLIN|POLLRDNORM. It only affects select(), which uses POLLRDNORM. poll() is not affected, because it uses POLLIN. Also, it only affects FreeBSD, because Linux skips the optimization implemented by the piece of code where the bug occurs. To check if txsync can be skipped, it is necessary to look for unseen TX space. However, this means comparing ring->cur against ring->tail, rather than ring->head against ring->tail (like nm_ring_empty() does). Sponsored by: Sunny Valley Networks

MFC r342300

2018-12-24T15:08:19Z

netmap: move buf_size validation code to its own function This code validates the netmap buf_size against the interface MTU and maximum descriptor size, to make sure the values are consistent. Moving this functionality to its own function is needed because this function is also called by Linux-specific code.

MFC r341624

2018-12-13T10:17:32Z

netmap: netmap_transmit should honor bpf packet tap hook This allows tcpdump to capture outbound kernel packets while in netmap mode Submitted by: Marc de la Gueronniere Reviewed by: vmaffione MFC after: 1 week Sponsored by: Verisign, Inc. Differential Revision: https://reviews.freebsd.org/D17896

MFC r341516, r341589

2018-12-13T10:13:29Z

netmap: align codebase to the current upstream (760279cfb2730a585) Changelist: - Replace netmap passthrough host support with a more general mechanism to call TXSYNC/RXSYNC from an in-kernel event-loop. No kernel threads are used to use this feature: the application is required to spawn a thread (or a process) and issue a SYNC_KLOOP_START (NIOCCTRL) command in the thread body. The kernel loop is executed by the ioctl implementation, which returns to userspace only when a different thread calls SYNC_KLOOP_STOP or the netmap file descriptor is closed. - Update the if_ptnet driver to cope with the new data structures, and prune all the obsolete ptnetmap code. - Add support for "null" netmap ports, useful to allocate netmap_if, netmap_ring and netmap buffers to be used by specialized applications (e.g. hypervisors). TXSYNC/RXSYNC on these ports have no effect. - Various fixes and code refactoring. Sponsored by: Sunny Valley Networks Differential Revision: https://reviews.freebsd.org/D18015

MFC r339639

2018-12-04T17:40:56Z

netmap: align codebase to the current upstream (sha 8374e1a7e6941) Changelist: - Move large parts of VALE code to a new file and header netmap_bdg.[ch]. This is useful to reuse the code within upcoming projects. - Improvements and bug fixes to pipes and monitors. - Introduce nm_os_onattach(), nm_os_onenter() and nm_os_onexit() to handle differences between FreeBSD and Linux. - Introduce some new helper functions to handle more host rings and fake rings (netmap_all_rings(), netmap_real_rings(), ...) - Added new sysctl to enable/disable hw checksum in emulated netmap mode. - nm_inject: add support for NS_MOREFRAG Approved by: gnn (mentor) Differential Revision: https://reviews.freebsd.org/D17364

Revert r330897:

2018-03-29T02:50:57Z

This was intended to be a non-functional change. It wasn't. The commit message was thus wrong. In addition it broke arm, and merged crypto related code. Revert with prejudice. This revert skips files touched in r316370 since that commit was since MFCed. This revert also skips files that require $FreeBSD$ property changes. Thank you to those who helped me get out of this mess including but not limited to gonzo, kevans, rgrimes. Requested by: gjb (re)