unmount, which causes error from nmount(2) call when performing
MNT_DELEXPORT over the directory which ceased to be a mount point.
The race is legitimate and innocent, but results in the chatty mountd.
Silence it by providing an distinguished error code for the situation,
and ignoring the error in mountd loop.
Based on the patch by: Andreas Longwitz <longwitz@incore.de>
Prodded and tested by: bdrewery
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
This change implements a notification (via devctl) to userland when
the kernel produces coredumps after a process has crashed.
devd can then run a specific command to produce a human readable crash
report. The command is most usually a helper that runs gdb/lldb
commands on the file/coredump pair. It's possible to use this
functionality for implementing automatic generation of crash reports.
devd(8) will be notified of the full path of the binary that crashed and
the full path of the coredump file.
is being done in the callout code and harmonizes the macro
use.:
1) The callout_active() will lie. Basically if a migration
is occuring and the callout is about to expire and the
migration has been deferred, the callout_active will no
longer return true until after the migration. This confuses
and breaks callers that are doing callout_init(&c, 1); such
as TCP.
2) The migration code had a bug in it where when migrating, if
a two calls to callout_reset came in and they both collided with
the callout on the wheel about to run, then the second call to
callout_reset would corrupt the list the callout wheel uses
putting the callout thread into a endless loop.
3) Per imp, I have fixed all the macro occurance in the code that
were for the most part being ignored.
Phabricator D1711 and looked at by lstewart and jhb and sbruno.
Reviewed by: kostikbel, imp, adrian, hselasky
MFC after: 3 days
Sponsored by: Netflix Inc.
allows the user to request administrative changes to individual devices
such as attach or detaching drivers or disabling and re-enabling devices.
- Add a new /dev/devctl2 character device which uses ioctls for device
requests. The ioctls use a common 'struct devreq' which is somewhat
similar to 'struct ifreq'.
- The ioctls identify the device to operate on via a string. This
string can either by the device's name, or it can be a bus-specific
address. (For unattached devices, a bus address is the only way to
locate a device.) Bus drivers register an eventhandler to claim
unrecognized device names that the driver recognizes as a valid address.
Two buses currently support addresses: ACPI recognizes any device
in the ACPI namespace via its full path starting with "\" and
the PCI bus driver recognizes an address specification of
'pci[<domain>:]<bus>:<slot>:<func>' (identical to the PCI selector
strings supported by pciconf).
- To make it easier to cut and paste, change the PnP location string
in the PCI bus driver to output a full PCI selector string rather
than 'slot=<slot> function=<func>'.
- Add a devctl(3) interface in libdevctl which provides a wrapper around
the ioctls and is the preferred interface for other userland code.
- Add a devctl(8) program which is a simple wrapper around the requests
supported by devctl(3).
- Add a device_is_suspended() function to check DF_SUSPENDED.
- Add a resource_unset_value() function that can be used to remove a
hint from the kernel environment. This is used to clear a
hint.<driver>.<unit>.disabled hint when re-enabling a boot-time
disabled device.
Reviewed by: imp (parts)
Requested by: imp (changing PCI location string)
Relnotes: yes
flag value is already exposed via dv_flags, just not the meaning of the
flags themselves. Use these constants to annotate devices that are
disabled or suspended in devinfo output.
in kernel config files..
put VERBOSE_SYSINIT in it's own option header so the one file,
init_main.c, can use it instead of requiring an entire kernel recompile
to change one file..
chances of finding problems related to wraparound sooner.
This comes from P4 change 167856 on 2009/08/26 around when we had problems
with the TCP stack with ticks after 24 days of uptime.
before pipeclose() is called, since for !PIPE_NAMED case, when peer is
already closed, the pipe pair memory is freed.
Submitted by: luke.tw@gmail.com
PR: 197246
Tested by: pho
MFC after: 3 days
subverted by userspace into cycle. Both umtx_propagate_priority() and
umtx_repropagate_priority() would then loop infinitely, owning the
spinlock.
Check for the cycle using standard Floyd' algorithm before doing the
pass in the affected functions. Add simple check for condition of
tricking the thread into a wait for itself, which could be easily
simulated by usermode without race.
Found by: Eric van Gyzen <eric@vangyzen.net>
In collaboration with: Eric van Gyzen <eric@vangyzen.net>
Tested by: pho
MFC after: 1 week
being held before sleeping.
This has bitten me (in ath(4)) once before and I'd like to see this
not bite anyone else.
Differential Revision: D1638
Reviewed by: jhb, hselasky
MFC after: 1 week
The core kernel part is patch file utimes.2008.4.diff from
pluknet@FreeBSD.org. I updated the code for API changes, added the manual
page and added compatibility code for old kernels. There is also audit and
Capsicum support.
A new UTIME_* constant might allow setting birthtimes in future.
Differential Revision: https://reviews.freebsd.org/D1426
Submitted by: pluknet (partially)
Reviewed by: delphij, pluknet, rwatson
Relnotes: yes
in bitfield argument is wrong, as it will be treated as bit 10, causing any
code printing >=10 bits with bit 10 on as having a trailing comma.
Newline (intended one) should be part of the format string (already present
in the examples).
Also fix grammar and kill EOL whitespace in comment while here.
PR: 195005
Approved by: bdrewery
FreeBSD developers need more time to review patches in the surrounding
areas like the TCP stack which are using MPSAFE callouts to restore
distribution of callouts on multiple CPUs.
Bump the __FreeBSD_version instead of reverting it.
Suggested by: kmacy, adrian, glebius and kib
Differential Revision: https://reviews.freebsd.org/D1438
We obtain a stable copy and store it in local 'fde' variable. Storing another
copy (based on aforementioned variable) does not serve any purpose.
No functional changes.
The only potential in-tree consumer (_fdrop) special-cased it and returns 0
0 on its own instead of calling badfo_close.
Remove the special case since it is not needed and very unlikely to encounter
anyway.
No objections from: kib
Prior to this change CLOCK_MONOTONIC could go backwards when the timecounter
hardware was changed via 'sysctl kern.timecounter.hardware'. This happened
because the vdso timehands update was missing the special treatment in
tc_windup() when changing timecounters.
Reviewed by: kib
in r277199. Acquire the neccessary reference in delist_dev_locked()
and inform destroy_devl() about it using CDP_UNREF_DTR flag.
Fix some style nits, add asserts.
Discussed with: hselasky
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
attachment to the process. Note that the command is not intended to
be a security measure, rather it is an obfuscation feature,
implemented for parity with other operating systems.
Discussed with: jilles, rwatson
Man page fixes by: rwatson
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
== SIG_DFL or SIG_IGN. Sloppy code does not fully initialize struct
sigaction for such cases, and being too demanding in the case of
default handler does not catch anything.
Reported and tested by: Alex Tutubalin <lexa@lexa.ru>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
- Close a migration race where callout_reset() failed to set the
CALLOUT_ACTIVE flag.
- Callout callback functions are now allowed to be protected by
spinlocks.
- Switching the callout CPU number cannot always be done on a
per-callout basis. See the updated timeout(9) manual page for more
information.
- The timeout(9) manual page has been updated to reflect how all the
functions inside the callout API are working. The manual page has
been made function oriented to make it easier to deduce how each of
the functions making up the callout API are working without having
to first read the whole manual page. Group all functions into a
handful of sections which should give a quick top-level overview
when the different functions should be used.
- The CALLOUT_SHAREDLOCK flag and its functionality has been removed
to reduce the complexity in the callout code and to avoid problems
about atomically stopping callouts via callout_stop(). If someone
needs it, it can be re-added. From my quick grep there are no
CALLOUT_SHAREDLOCK clients in the kernel.
- A new callout API function named "callout_drain_async()" has been
added. See the updated timeout(9) manual page for a complete
description.
- Update the callout clients in the "kern/" folder to use the callout
API properly, like cv_timedwait(). Previously there was some custom
sleepqueue code in the callout subsystem, which has been removed,
because we now allow callouts to be protected by spinlocks. This
allows us to tear down the callout like done with regular mutexes,
and a "td_slpmutex" has been added to "struct thread" to atomically
teardown the "td_slpcallout". Further the "TDF_TIMOFAIL" and
"SWT_SLEEPQTIMO" states can now be completely removed. Currently
they are marked as available and will be cleaned up in a follow up
commit.
- Bump the __FreeBSD_version to indicate kernel modules need
recompilation.
- There has been several reports that this patch "seems to squash a
serious bug leading to a callout timeout and panic".
Kernel build testing: all architectures were built
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D1438
Sponsored by: Mellanox Technologies
Reviewed by: jhb, adrian, sbruno and emaste
more generally make it easier to extend 'struct mbuf in the future', make
a number of changes to the data structure:
- As we anticipate embedding mbufs headers within variable-size regions of
memory in the future, change the definitions of byte arrays embedded in
mbufs to be of size [0] rather than [MLEN] and [MHLEN]. In fact, the
cxgbe driver already uses 'struct mbuf' on the front of other storage
sizes, but we would like the global mbuf allocator do be able to do this
as well.
- Fold 'struct m_hdr' into 'struct mbuf' itself, eliminating a set of
macros that aliased 'mh_foo' field names to 'm_foo' names such as
'm_next'. These present a particular problem as we would like to add
new mbuf-header fields -- e.g., 'm_size' -- that, if similarly named via
macros, would introduce collisions with many other variable names in the
kernel.
- Rename 'struct m_ext' to 'struct struct_m_ext' so that we can add
compile-time assertions without bumping into the still-extant 'm_ext'
macro.
- Remove the MSIZE compile-time assertion for 'struct mbuf', but add new
assertions for alignment of embedded data arrays (64-bit alignment even
on 32-bit platforms), and for the sizes the mbuf header, packet header,
and m_ext structure.
- Document that these assertions exist in comments in mbuf.h.
This change is not intended to cause (non-trivial) behavioural
differences, but is a precursor to further mbuf-allocator work.
Differential Revision: https://reviews.freebsd.org/D1483
Reviewed by: bz, gnn, np, glebius ("go ahead, I trust you")
Sponsored by: EMC / Isilon Storage Division
"delist_dev()" function. Make sure the character device structure
doesn't go away until the end of the "destroy_dev()" function due to
concurrently running cleanup code inside "devfs_populate()".
MFC after: 1 week
Reported by: dchagin@
in FreeBSD 7 that has not been used since. It contains a number
of unresolved bugs including an inverted bcopy() and incorrect
handling of read-only mbufs using internal storage. Removing this
unused code is substantially essier than fixing it in order to
update it to the coming mbuf world order -- but it can always be
restored from revision history if it turns out to prove useful for
future work.
Pointed out by: jmallett
Sponsored by: EMC / Isilon Storage Division
by reinitializing the 'freestate' pointer after freeing the memory.
Obtained from: HardenedBSD (71fab80c5dd3034b71a29a61064625018671bbeb)
PR: 194525
Submitted by: Oliver Pinter <oliver.pinter@hardenedbsd.org>
MFC after: 2 weeks
decade: m_pulldown() is willing to consider ordinary mbufs writable.
Retain another, related, and also outdated comment, but with a caveat
that it is partially stale. Do not, for now, address the problem that
it raises (that only EXT_CLUSTER external storage is considered
writable, regardless of the results of M_WRITABLE() on the mbuf).
MFC after: 3 days
Sponsored by: EMC / Isilon Storage Division
EOPNOTSUPP. The current behavior can mask real quiesce errors since
devclass_quiesce_driver() stops iterating over drivers as soon as it
gets an error (incluiding EOPNOTSUPP), but the caller it returns the
error to explicitly ignores EOPNOTSUPP.
Reviewed by: imp
kernel via the global cpuset_domain[] array. To export these to userland,
add a CPU_WHICH_DOMAIN level that can be used to fetch the mask for a
specific domain. Add a -d flag to cpuset(1) that can be used to fetch
the mask for a given domain.
Differential Revision: https://reviews.freebsd.org/D1232
Submitted by: jeff (kernel bits)
Reviewed by: adrian, jeff
with calls to the centralised macros, reducing direct use of MLEN and
MHLEN.
Differential Revision: https://reviews.freebsd.org/D1444
Reviewed by: bz
Sponsored by: EMC / Isilon Storage Division
code in sys/kern/kern_dump.c. Most dumpsys() implementations are nearly
identical and simply redefine a number of constants and helper subroutines;
a generic implementation will make it easier to implement features around
kernel core dumps. This change does not alter any minidump code and should
have no functional impact.
PR: 193873
Differential Revision: https://reviews.freebsd.org/D904
Submitted by: Conrad Meyer <conrad.meyer@isilon.com>
Reviewed by: jhibbits (earlier version)
Sponsored by: EMC / Isilon Storage Division
may perform a blocking memory allocation, which is unsafe when holding a
mutex.
Differential Revision: https://reviews.freebsd.org/D1443
Reviewed by: rwatson
MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division
may also halt in C2 and not just C3 (it seems that in some cases the BIOS
advertises its C3 state as a C2 state in _CST). Just play it safe and
disable both C2 and C3 states if a user forces the use of the TSC as the
timecounter on such CPUs.
PR: 192316
Differential Revision: https://reviews.freebsd.org/D1441
No objection from: jkim
MFC after: 1 week
the knowledge of mbuf layout, and in particular constants such as M_EXT,
MLEN, MHLEN, and so on, in mbuf consumers by unifying various alignment
utility functions (M_ALIGN(), MH_ALIGN(), MEXT_ALIGN() in a single
M_ALIGN() macro, implemented by a now-inlined m_align() function:
- Move m_align() from uipc_mbuf.c to mbuf.h; mark as __inline.
- Reimplement M_ALIGN(), MH_ALIGN(), and MEXT_ALIGN() using m_align().
- Update consumers around the tree to simply use M_ALIGN().
This change eliminates a number of cases where mbuf consumers must be aware
of whether or not mbufs returned by the allocator use external storage, but
also assumptions about the size of the returned mbuf. This will make it
easier to introduce changes in how we use external storage, as well as
features such as variable-size mbufs.
Differential Revision: https://reviews.freebsd.org/D1436
Reviewed by: glebius, trasz, gnn, bz
Sponsored by: EMC / Isilon Storage Division
Phabric: https://reviews.freebsd.org/D1247
Reviewed by: jhb, avg
Sponsored by: Spectra Logic Corporation
sys/kern_subr_taskqueue.c:
Modify taskqueue_drain_all() processing to use a temporary
"barrier task", rather than rely on a user task that may
be destroyed during taskqueue_drain_all()'s execution. The
barrier task is queued behind all previously queued tasks
and then has its priority elevated so that future tasks
cannot pass it in the queue.
Use a similar barrier scheme to drain threads processing
current tasks. This requires taskqueue_run_locked() to
insert and remove the taskqueue_busy object for the running
thread for every task processed.
share/man/man9/taskqueue.9:
Remove warning about live-lock issues with taskqueue_drain_all()
and indicate that it does not wait for tasks queued after
it begins processing.
in r276564, change path type to char * (pathnames are always char *).
And remove bogus casts of malloc().
kern___getcwd() internally doesn't actually use or support u_char *
paths, except to copy them to a normal char * path.
These changes are not visible to libc as libc/gen/getcwd.c misdeclares
__getcwd() as taking a plain char * path.
While here remove _SYS_SYSPROTO_H_ for __getcwd() syscall as
we always have sysproto.h.
Pointed out by: bde
MFC after: 1 week
clients, hence they might not handle it very well. This change allows
debugging mutex problems with kernel console drivers when
"debug.witness.skipspin=0" is set in the boot environment.
MFC after: 1 week
witness printouts in the console driver clients can cause this mutex
to recurse by calls to "printf()" from witness for example. In
particular this can happen if "debug.witness.skipspin=0" is set in the
boot environment.
MFC after: 1 week
locks/unlocks the vnode and does a VOP_GETATTR()
for the SEEK_END case. This is safe to do, since
lf_advlock{async}() only uses the size argument
for the SEEK_END case.
The NFSv4 server needs this when
vfs.nfsd.enable_locallocks!=0 since locking the
vnode results in a LOR that can cause a deadlock
for the nfsd threads.
Reviewed by: kib
MFC after: 1 week
the created file name was cached. Use the flag for core dumps.
Requested by: rpaulo
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
(UTC) rather than the archaic (GMT) in comments. Except where the
comments are making fun of people doing this (and pedants who insist
on the new terms).
why there could appear a zero-sized mbufs in socket buffers.
A proper fix would be to divorce record socket buffers and stream
socket buffers, and divorce pru_send that accepts normal data from
pru_send that accepts control data.
in sbappend_locked() and sbappendrecord_locked().
This is a quick fix to the panic introduced by r274712.
A proper solution should be to make sosend_generic() avoid calling
pru_send() with NULL mbuf for the protocols that do not understand
control messages. Those protocols that understand control messages,
should be able to receive NULL mbuf, if control is non-NULL.
into namecache, to avoid cache trashing when doing large operations.
E.g., tar archive extraction is not usually followed by access to many
of the files created.
Right now, each VOP_LOOKUP() implementation explicitely knowns about
this quirk and tests for both MAKEENTRY flag presence and op != CREATE
to make the call to cache_enter(). Centralize the handling of the
quirk into VFS, by deciding to cache only by MAKEENTRY flag in VOP.
VFS now sets NOCACHE flag for CREATE namei() calls.
Note that the change in semantic is backward-compatible and could be
merged to the stable branch, and is compatible with non-changed
third-party filesystems which correctly handle MAKEENTRY.
Suggested by: Chris Torek <torek@pi-coral.com>
Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
the orphaned descendants. Base of the API is modelled after the same
feature from the DragonFlyBSD.
Requested by: bapt
Reviewed by: jilles (previous version)
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
A _NEW flag passed to _init_flags() to avoid check for double-init.
Differential Revision: https://reviews.freebsd.org/D1208
Reviewed by: jhb, wblock
MFC after: 1 Month
feature is to quisce the system before suspend.
Stop is implemented by reusing the thread_single(9) with the special
mode SINGLE_ALLPROC. SINGLE_ALLPROC differs from the existing
single-threading modes by allowing (requiring) caller to operate on
other process. Interruptible sleeps for !TDF_SBDRY threads are
suspended like SIGSTOP does it, instead of aborting the sleep, like
SINGLE_NO_EXIT, to avoid spurious EINTRs on resume.
Provide debugging sysctl debug.stop_all_proc, which causes total stop
and suspends syncer, while waiting for variable reset for resume. It
is used for debugging; should be removed after the real use of the
interface is added.
In collaboration with: pho
Discussed with: avg
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
filesystem specified VFCF_SBDRY flag, i.e. for NFS.
There are two issues with the sleeps. First, applications may get
unexpected EINTR from the disk i/o syscalls. Second, interruptible
sleep allows the stop of the process, and since mount point is
referenced while thread sleeps, unmount cannot free mount point
structure' memory, blocking unmount indefinitely.
Even for NFS, it is probably only reasonable to enable PCATCH for intr
mounts, but this information is currently not available at VFS level.
Reported and tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
creating delayed write buffers belonging to the reclaimed vnode. Put
the buffer cleanup code after inactivation.
Add asserts that ensure that buffer queues are empty and add BO_DEAD
flag for bufobj to check that no buffers are added after the cleanup.
BO_DEAD is only used by INVARIANTS-enabled kernels.
Reported and tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Since VFS does not/cannot stop writes, sync might run indefinitely, or
be a wrong thing to do at all. E. g. NFS ignores VFS_SYNC() for
forced unmounts, since non-responding server does not allow sync to
finish. On the other hand, filesystems can and do stop writes using
fs-specific facilities, and should already fully flush caches in
VFS_UNMOUNT() due to the race.
Adjust msdosfs tp sync in unmount for forced call, to accomodate the
new behaviour. Note that it is still racy, since writes are not
stopped.
Discussed with: avg, bjk, mckusick
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
to be called before suspension and after resume, correspondingly. The
syncer_suspend() ensures that all filesystems dirty data and metadata
are saved to the permanent storage, and stops kernel threads which
might modify filesystems. The syncer_resume() restores stopped
threads.
For now, only syncer is stopped. This is needed, because each sync
loop causes superblock updates for UFS.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
the vnode owning the buffer is not locked. More, it cannot be locked
safely, since getnewbuf_reuse_bp() is called from newbuf(), and some
other vnode is already locked, for which reused buffer will be
reassigned.
As the consequence, reclamation of the owning vnode could go in
parallel, in particular, the call to vnode_destroy_vobject(), which
deallocates the vm object and zeroes the v_bufobj->bo_object. Note
that the pages wired by the buffer are left wired and can be safely
freed by the vfs_vmio_release() without the need for the vm object
lock. Also, seeing stale pointer to the v_object is safe due to vm
object type stability.
Check for bo_bufobj != NULL and cache the value in local variable to
avoid trying to lock NULL vm object.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
preparation for the global stop commit.
Move the code to weed suspended or sleeping threads into the
appropriate state, into the helper weed_inhib(). Current code already
has deep nesting and hard to follow [1].
Add currently useless helper remain_for_mode(), which returns the
count of threads which are allowed to run, according to the
single-threading mode.
In thread_single_end(), do not save curthread into local variable, it
is unused after, except to find curproc.
Remove stray empty line.
Requested by: avg [1]
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
for the suspension.
Currently, the loop performs uninterruptible cv_wait(9) call, which
prevents suspension until child allows further execution of parent.
If child is stopped, suspension or single-threading is delayed
indefinitely.
Create a helper thread_suspend_check_needed() to identify the need for
a call to thread_suspend_check(). It is required since call to the
thread_suspend_check() cannot be safely done while owning the child
(p2) process lock. Only when suspension is needed, drop p2 lock and
call thread_suspend_check(). Perform wait for cv with timeout, in
case suspend is requested after wait started; I do not see a better
way to interrupt the wait.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
multithreaded status of the process.
The stopped state must be cleared before P_WEXIT is set. A stop
signal delivered just before first PROC_LOCK() block in exit1(9) would
put the process into pending stop with P_WEXIT set or assertion
triggered. Also recheck for the suspension after failed
thread_single(9) call, since process lock could be dropped.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
In the old days callout(9) had 1 tick precision and that was inadequate
for some uses, e.g. DTrace profile module, so we had to emulate cyclic
API and behavior. Now we can directly use callout(9) in the very few
places where cyclic was used.
Differential Revision: https://reviews.freebsd.org/D1161
Reviewed by: gnn, jhb, markj
MFC after: 2 weeks
Provide pru_ready for AF_LOCAL sockets. Local sockets sendsdata directly
to the receive buffer of the peer, thus pru_ready also works on the peer
socket.
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
sending not ready data:
o Add new flag to pru_send() flags - PRUS_NOTREADY.
o Add new protocol method pru_ready().
Sponsored by: Nginx, Inc.
Sponsored by: Netflix
o Introduce a notion of "not ready" mbufs in socket buffers. These
mbufs are now being populated by some I/O in background and are
referenced outside. This forces following implications:
- An mbuf which is "not ready" can't be taken out of the buffer.
- An mbuf that is behind a "not ready" in the queue neither.
- If sockbet buffer is flushed, then "not ready" mbufs shouln't be
freed.
o In struct sockbuf the sb_cc field is split into sb_ccc and sb_acc.
The sb_ccc stands for ""claimed character count", or "committed
character count". And the sb_acc is "available character count".
Consumers of socket buffer API shouldn't already access them directly,
but use sbused() and sbavail() respectively.
o Not ready mbufs are marked with M_NOTREADY, and ready but blocked ones
with M_BLOCKED.
o New field sb_fnrdy points to the first not ready mbuf, to avoid linear
search.
o New function sbready() is provided to activate certain amount of mbufs
in a socket buffer.
A special note on SCTP:
SCTP has its own sockbufs. Unfortunately, FreeBSD stack doesn't yet
allow protocol specific sockbufs. Thus, SCTP does some hacks to make
itself compatible with FreeBSD: it manages sockbufs on its own, but keeps
sb_cc updated to inform the stack of amount of data in them. The new
notion of "not ready" data isn't supported by SCTP. Instead, only a
mechanical substitute is done: s/sb_cc/sb_ccc/.
A proper solution would be to take away struct sockbuf from struct
socket and allow protocols to implement their own socket buffers, like
SCTP already does. This was discussed with rrs@.
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
crowded as we now are at about 70k. Bump the limit to 1MB instead
which is still quite a reasonable limit and allows for future growth
of this file and possible future expansion to additional data.
MFC After: 2 weeks
recursion on mutex initialization.
The only places where the recursive acquire is performed are read and
write filters, since knlist, which uses the pipe pair mutex as lock,
is locked when filter is called.
The recursion was added in r93296, and consistent locking for
kn_fop->f_event() introduced in r133741.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
