dispatched without Giant, and add NETISR_FORCEQUEUE, which allows specific
netisr handlers to always be dispatched via a queue (deferred). Mark the
usb and if_ppp netisr handlers as NETISR_FORCEQUEUE, and explicitly
acquire Giant in those handlers.
Previously, any netisr handler not marked NETISR_MPSAFE would necessarily
run deferred and with Giant acquired. This change removes Giant
scaffolding from the netisr infrastructure, but NETISR_FORCEQUEUE allows
non-MPSAFE handlers to continue to force deferred dispatch so as to avoid
lock order reversals between their acqusition of Giant and any calling
context.
It is likely we will be able to remove NETISR_FORCEQUEUE once
IFF_NEEDSGIANT is removed, as non-MPSAFE usb and if_ppp drivers will no
longer be supported.
Reviewed by: bz
MFC after: 1 month
X-MFC note: We can't remove NETISR_MPSAFE from stable/7 for KPI reasons,
but the rest can go back.
University of Washington copyrights, which include the
advertising clause. Move $NetBSD$ into standard location for
FreeBSD source files, and normalize formatting.
MFC after: 3 days
- Introduce a subsystem mutex, natm_mtx, manipulated with accessor macros
NATM_LOCK_INIT(), NATM_LOCK(), NATM_UNLOCK(), NATM_LOCK_ASSERT(). It
protects the consistency of pcb-related data structures. Finer grained
locking is possible, but should be done in the context of specific
measurements (as very little work is done in netnatm -- most is in the
ATM device driver or socket layer, so there's probably not much
contention).
- Remove GIANT_REQUIRED, mark as NETISR_MPSAFE, remove
NET_NEEDS_GIANT("netnatm").
- Conditionally acquire Giant when entering network interfaces for
ifp->if_ioctl() using IFF_LOCKGIANT(ifp)/IFF_UNLOCKGIANT(ifp) in order
to coexist with non-MPSAFE atm ifnet drivers..
- De-spl.
MFC after: 2 weeks
Reviewed by: harti, bms (various versions)
whether or not the isr needs to hold Giant when running; Giant-less
operation is also controlled by the setting of debug_mpsafenet
o mark all netisr's except NETISR_IP as needing Giant
o add a GIANT_REQUIRED assertion to the top of netisr's that need Giant
o pickup Giant (when debug_mpsafenet is 1) inside ip_input before
calling up with a packet
o change netisr handling so swi_net runs w/o Giant; instead we grab
Giant before invoking handlers based on whether the handler needs Giant
o change netisr handling so that netisr's that are marked MPSAFE may
have multiple instances active at a time
o add netisr statistics for packets dropped because the isr is inactive
Supported by: FreeBSD Foundation
function prototypes. Use LIST_FOREACH instead of explicit loops.
The indentation of functions indendet by 4 space have been left alone.
2-space indented functions have been re-indented.
drain routines are done by swi_net, which allows for better queue control
at some future point. Packets may also be directly dispatched to a netisr
instead of queued, this may be of interest at some installations, but
currently defaults to off.
Reviewed by: hsu, silby, jayanth, sam
Sponsored by: DARPA, NAI Labs
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.
Tested on: i386, alpha, sparc64
before adding/removing packets from the queue. Also, the if_obytes and
if_omcasts fields should only be manipulated under protection of the mutex.
IF_ENQUEUE, IF_PREPEND, and IF_DEQUEUE perform all necessary locking on
the queue. An IF_LOCK macro is provided, as well as the old (mutex-less)
versions of the macros in the form _IF_ENQUEUE, _IF_QFULL, for code which
needs them, but their use is discouraged.
Two new macros are introduced: IF_DRAIN() to drain a queue, and IF_HANDOFF,
which takes care of locking/enqueue, and also statistics updating/start
if necessary.
include this in all kernels. Declare some const *intrq_present
variables that can be checked by a module prior to using *intrq
to queue data.
Make the if_tun module capable of processing atm, ip, ip6, ipx,
natm and netatalk packets when TUNSIFHEAD is ioctl()d on.
Review not required by: freebsd-hackers
