Implement the linux_io_* syscalls (AIO). They are only enabled if the native
AIO code is available (either compiled in to the kernel or as a module) at
the time the functions are used. If the AIO stuff is not available there
will be a ENOSYS.
From the submitter:
---snip---
DESIGN NOTES:
1. Linux permits a process to own multiple AIO queues (distinguished by
"context"), but FreeBSD creates only one single AIO queue per process.
My code maintains a request queue (STAILQ of queue(3)) per "context",
and throws all AIO requests of all contexts owned by a process into
the single FreeBSD per-process AIO queue.
When the process calls io_destroy(2), io_getevents(2), io_submit(2) and
io_cancel(2), my code can pick out requests owned by the specified context
from the single FreeBSD per-process AIO queue according to the per-context
request queues maintained by my code.
2. The request queue maintained by my code stores contrast information between
Linux IO control blocks (struct linux_iocb) and FreeBSD IO control blocks
(struct aiocb). FreeBSD IO control block actually exists in userland memory
space, required by FreeBSD native aio_XXXXXX(2).
3. It is quite troubling that the function io_getevents() of libaio-0.3.105
needs to use Linux-specific "struct aio_ring", which is a partial mirror
of context in user space. I would rather take the address of context in
kernel as the context ID, but the io_getevents() of libaio forces me to
take the address of the "ring" in user space as the context ID.
To my surprise, one comment line in the file "io_getevents.c" of
libaio-0.3.105 reads:
Ben will hate me for this
REFERENCE:
1. Linux kernel source code: http://www.kernel.org/pub/linux/kernel/v2.6/
(include/linux/aio_abi.h, fs/aio.c)
2. Linux manual pages: http://www.kernel.org/pub/linux/docs/manpages/
(io_setup(2), io_destroy(2), io_getevents(2), io_submit(2), io_cancel(2))
3. Linux Scalability Effort: http://lse.sourceforge.net/io/aio.html
The design notes: http://lse.sourceforge.net/io/aionotes.txt
4. The package libaio, both source and binary:
http://rpmfind.net/linux/rpm2html/search.php?query=libaio
Simple transparent interface to Linux AIO system calls.
5. Libaio-oracle: http://oss.oracle.com/projects/libaio-oracle/
POSIX AIO implementation based on Linux AIO system calls (depending on
libaio).
---snip---
Submitted by: Li, Xiao <intron@intron.ac>
if backward copatibility options are present) from attempting
to free memory that wasn't allocated. This is an old bug, and
previously it would attempt to free a null pointer. I noticed
this bug when working on the previous revision, but forgot to
fix it.
Security: local DoS
Reported by: Peter Holm
MFC after: 3 days
method is defined, to avoid memory being modified after free.
Temporarily increase refcount in destroy_devl() to avoid a double free
if dev_rel() is called while waiting for thread count to reach zero.
removals, including failures, into the callwheel.
XXX: Most of the CTR() macros are called with callout_lock spin mutex
held, thus won't be logged into file, if KTR_ALQ is used. Moving the
CTR() macros out from the spinlocked code would require copying of all
arguments. I'm too lazy to do this.
calls are not used by libthr in RELENG_6 and HEAD, it is only used by
the libthr in RELENG-5, the _umtx_op system call can do more incremental
dirty works than these two system calls without having to introduce new
system calls or throw away old system calls when things are going on.
unmount when mp structure is reused while waiting for coveredvp lock.
Introduce struct mount generation count, increment it on each reuse and
compare the generations before and after obtaining the coveredvp lock.
Reviewed by: tegge, pjd
Approved by: pjd (mentor)
MFC after: 2 weeks
Split subr_clock.c in two parts (by repo-copy):
subr_clock.c contains generic RTC and calendaric stuff. etc.
subr_rtc.c contains the newbus'ified RTC interface.
Centralize the machdep.{adjkerntz,disable_rtc_set,wall_cmos_clock}
sysctls and associated variables into subr_clock.c. They are
not machine dependent and we have generic code that relies on being
present so they are not even optional.
Remove workarounds for tty_refcount beeing 0, this will be fixed differently
later.
Back out rev 1.145 since we initialize the tty struct from scratch and bad
things can't happen anymore.
ioctls passing integer arguments should use the _IOWINT() macro.
This fixes a lot of ioctl's not working on sparc64, most notable
being keyboard/syscons ioctls.
Full ABI compatibility is provided, with the bonus of fixing the
handling of old ioctls on sparc64.
Reviewed by: bde (with contributions)
Tested by: emax, marius
MFC after: 1 week
sync() and sync_fsync() without losing MNT_ASYNC. Add MNTK_ASYNC flag
which is set only when MNT_ASYNC is set and mnt_noasync is zero, and
check that flag instead of MNT_ASYNC before initiating async io.
programs to find out exactly which events were registered and which were
returned... This should be lower in kern_kevent, but that would require
special munging due to locks and the functions used to copyin/copyout
kevents...
If someone wants to teach ktrace how to output pretty kevents, I have a
kevent prety printer that can be used...
you can't call tty_clone afterwords. OpenBSD and NetBSD both fail the
open call in that case, so we should do so as well. This can
be done in ctty_clone by returning with *dev==NULL. Admittedly this
causes open to return ENOENT, instead of ENXIO as on the other BSDs,
but this way requires the least touching of code.
Submitted by: Nate Eldredge <nge@cs.hmc.edu>
PR: 83375
MFC: 1 week
the entire record when a non-data mbuf is removed in the soreceive() path.
This only triggers a panic directly when compiled with INVARIANTS.
PR: 38495
Submitted by: James Juran
MFC after: 1 week
returns the previous value that the "add" effected (In
this case we are adding -1), afterwhich we compare it
to '0'... to see if we free the mbuf... we should
be comparing it to '1'... Note that this only effects
when there is contention since there is a first part
to the comparison that checks to see if its '1'. So
this bug would only crop up if two CPU's are trying
to free the same mbuf refcount at the same time. This
will happen in SCTP but I doubt can happen in TCP or
UDP.
PR: N/A
Submitted by: rrs
Reviewed by: gnn,sam
Approved by: gnn,sam
appears to be serving a useful purpose, as it was used during initial
development of MAC support for System V IPC.
MFC after: 1 month
Obtained from: TrustedBSD Project
Suggested by: Christopher dot Vance at SPARTA dot com
other problems while labels were first being added to various kernel
objects. They have outlived their usefulness.
MFC after: 1 month
Suggested by: Christopher dot Vance at SPARTA dot com
Obtained from: TrustedBSD Project
