Commit Graph

8 Commits

Author SHA1 Message Date
Sepherosa Ziehau
1321c5029e buf_ring/drbr: Add buf_ring_peek_clear_sc and use it in drbr_peek
Unlike buf_ring_peek, it only supports single consumer mode, and it
clears the cons_head if DEBUG_BUFRING/INVARIANTS is defined.

The normal use case of drbr_peek for network drivers is:

m = drbr_peek(br);
err = hw_spec_encap(&m); /* could m_defrag/m_collapse */
(*)
if (err) {
    if (m == NULL)
        drbr_advance(br);
    else
        drbr_putback(br, m);
    /* break the loop */
}
drbr_advance(br);

The race is:
If hw_spec_encap() m_defrag or m_collapse the mbuf, i.e. the old mbuf
was freed, or like the Hyper-V's network driver, that transmission-
done does not even require the TX lock; then on the other CPU at the
(*) time, the freed mbuf could be recycled and being drbr_enqueue even
before the current CPU had the chance to call drbr_{advance,putback}.
This triggers a panic in drbr_enqueue duplicated element check, if
DEBUG_BUFRING/INVARIANTS is defined.

Use buf_ring_peek_clear_sc() in drbr_peek() to fix the above race.

This change is a NO-OP, if neither DEBUG_BUFRING nor INVARIANTS are
defined.

MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D5416
2016-02-29 03:54:51 +00:00
Gleb Smirnoff
772e66a6fc Move ALTQ from contrib to net/altq. The ALTQ code is for many years
discontinued by its initial authors. In FreeBSD the code was already
slightly edited during the pf(4) SMP project. It is about to be edited
more in the projects/ifnet. Moving out of contrib also allows to remove
several hacks to the make glue.

Reviewed by:	net@
2015-04-16 20:22:40 +00:00
Bjoern A. Zeeb
0110795a35 Remove duplicate declaraton of the if_inc_counter() function after r272244.
if_var.h has the expected on and if_var.h include ifq.h and thus we get
duplicates.  It seems only one cavium ethernet file actually includes ifq.h
directly which might be another cleanup to be done but need to test first.
2014-09-28 15:38:21 +00:00
Gleb Smirnoff
bd071d4d19 - Remove empty wrappers ether_poll_[de]register_drv(). [1]
- Move polling(9) declarations out of ifq.h back to if_var.h
  they are absolutely unrelated to queues.

Submitted by:	Mikhail <mp lenta.ru> [1]
2014-09-28 14:05:18 +00:00
Gleb Smirnoff
112f50ffb2 Finally, convert counters in struct ifnet to counter(9).
Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2014-09-28 08:57:07 +00:00
Gleb Smirnoff
56b61ca27a Remove ifq_drops from struct ifqueue. Now queue drops are accounted in
struct ifnet if_oqdrops.

Some netgraph modules used ifqueue w/o ifnet. Accounting of queue drops
is simply removed from them. There were no API to read this statistic.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2014-09-19 09:01:19 +00:00
Marcel Moolenaar
62d76917b8 Introduce a procedural interface to the ifnet structure. The new
interface allows the ifnet structure to be defined as an opaque
type in NIC drivers.  This then allows the ifnet structure to be
changed without a need to change or recompile NIC drivers.

Put differently, NIC drivers can be written and compiled once and
be used with different network stack implementations, provided of
course that those network stack implementations have an API and
ABI compatible interface.

This commit introduces the 'if_t' type to replace 'struct ifnet *'
as the type of a network interface. The 'if_t' type is defined as
'void *' to enable the compiler to perform type conversion to
'struct ifnet *' and vice versa where needed and without warnings.
The functions that implement the API are the only functions that
need to have an explicit cast.

The MII code has been converted to use the driver API to avoid
unnecessary code churn. Code churn comes from having to work with
both converted and unconverted drivers in correlation with having
callback functions that take an interface. By converting the MII
code first, the callback functions can be defined so that the
compiler will perform the typecasts automatically.

As soon as all drivers have been converted, the if_t type can be
redefined as needed and the API functions can be fix to not need
an explicit cast.

The immediate benefactors of this change are:
1.  Juniper Networks - The network stack implementation in Junos
    is entirely different from FreeBSD's one and this change
    allows Juniper to build "stock" NIC drivers that can be used
    in combination with both the FreeBSD and Junos stacks.
2.  FreeBSD - This change opens the door towards changing ifnet
    and implementing new features and optimizations in the network
    stack without it requiring a change in the many NIC drivers
    FreeBSD has.

Submitted by:	Anuranjan Shukla <anshukla@juniper.net>
Reviewed by:	glebius@
Obtained from:	Juniper Networks, Inc.
2014-06-02 17:54:39 +00:00
Andre Oppermann
ded7d20fc5 Move all interface queue related structures, macros and definitions
from net/if_var to it own new net/ifq.h.

For now net/ifq.h is unconditionally included through net/if_var.h.

This is a mechanical change in preparation to make struct ifnet and
the individual interface queue mechanisms opaque.

Discussed with:	glebius
Sponsored by:	The FreeBSD Foundation
2013-10-29 17:48:08 +00:00