$OpenBSD: ifq_deq_begin.9,v 1.5 2021/03/20 21:02:56 sthen Exp $
Copyright (c) 2015 David Gwynne <dlg@openbsd.org>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.Dd $Mdocdate: May 29 2020 $ .Dt IFQ_DEQ_BEGIN 9 .Os .Sh NAME .Nm ifq_deq_begin , .Nm ifq_deq_commit , .Nm ifq_deq_rollback .Nd dequeue an mbuf from an interface sending queue .Sh SYNOPSIS n net/if_var.h .Ft struct mbuf * .Fn ifq_deq_begin "struct ifqueue *ifq" .Ft void .Fn ifq_deq_commit "struct ifqueue *ifq" "struct mbuf *m" .Ft void .Fn ifq_deq_rollback "struct ifqueue *ifq" "struct mbuf *m" .Sh DESCRIPTION The ifq_deq_* set of functions provides a non-atomic alternative to .Xr ifq_dequeue 9 . Their use is discouraged, code should use .Xr ifq_dequeue 9 whenever possible. l -tag -width Ds t Fn ifq_deq_begin "struct ifqueue *ifq" Get a reference to the next mbuf to be transmitted from the .Fa ifq interface send queue. If an mbuf is to be transmitted, also acquire a lock on the send queue to exclude modification or freeing of the referenced mbuf. Its packet header must not be modified until the mbuf has been dequeued with .Fn ifq_deq_commit . t Fn ifq_deq_commit "struct ifqueue *ifq" "struct mbuf *m" Dequeue the mbuf .Fa m that was referenced by a previous call to .Fn ifq_deq_begin and release the lock on .Fa ifq . t Fn ifq_deq_rollback "struct ifqueue *ifq" "struct mbuf *m" Release the lock on the interface send queue .Fa ifq that was acquired while a reference to .Fa m was being held. .El .Sh CONTEXT .Fn ifq_deq_begin , .Fn ifq_deq_commit , and .Fn ifq_deq_rollback can be called during autoconf, from process context, or from interrupt context. .Sh RETURN VALUES .Fn ifq_deq_begin returns the next mbuf to be transmitted by the interface. If no packet is available for transmission, .Dv NULL is returned. .Sh SEE ALSO .Xr ifq_dequeue 9
Copyright (c) 2015 David Gwynne <dlg@openbsd.org>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.Dd $Mdocdate: May 29 2020 $ .Dt IFQ_DEQ_BEGIN 9 .Os .Sh NAME .Nm ifq_deq_begin , .Nm ifq_deq_commit , .Nm ifq_deq_rollback .Nd dequeue an mbuf from an interface sending queue .Sh SYNOPSIS n net/if_var.h .Ft struct mbuf * .Fn ifq_deq_begin "struct ifqueue *ifq" .Ft void .Fn ifq_deq_commit "struct ifqueue *ifq" "struct mbuf *m" .Ft void .Fn ifq_deq_rollback "struct ifqueue *ifq" "struct mbuf *m" .Sh DESCRIPTION The ifq_deq_* set of functions provides a non-atomic alternative to .Xr ifq_dequeue 9 . Their use is discouraged, code should use .Xr ifq_dequeue 9 whenever possible. l -tag -width Ds t Fn ifq_deq_begin "struct ifqueue *ifq" Get a reference to the next mbuf to be transmitted from the .Fa ifq interface send queue. If an mbuf is to be transmitted, also acquire a lock on the send queue to exclude modification or freeing of the referenced mbuf. Its packet header must not be modified until the mbuf has been dequeued with .Fn ifq_deq_commit . t Fn ifq_deq_commit "struct ifqueue *ifq" "struct mbuf *m" Dequeue the mbuf .Fa m that was referenced by a previous call to .Fn ifq_deq_begin and release the lock on .Fa ifq . t Fn ifq_deq_rollback "struct ifqueue *ifq" "struct mbuf *m" Release the lock on the interface send queue .Fa ifq that was acquired while a reference to .Fa m was being held. .El .Sh CONTEXT .Fn ifq_deq_begin , .Fn ifq_deq_commit , and .Fn ifq_deq_rollback can be called during autoconf, from process context, or from interrupt context. .Sh RETURN VALUES .Fn ifq_deq_begin returns the next mbuf to be transmitted by the interface. If no packet is available for transmission, .Dv NULL is returned. .Sh SEE ALSO .Xr ifq_dequeue 9