- If possible, context switch to the thread directly in sched_ithd(),
rather than triggering a delayed ast reschedule.
- Disable interrupts while restoring fpu state in the trap handler,
in order to ensure that we are not preempted in the middle, which
could cause migration to another cpu.
Reviewed by: peter
Tested by: peter (alpha)
* Optimise the return path for syscalls so that they only restore a minimal
set of registers instead of performing a full exception_return.
A new flag in the trapframe indicates that the frame only holds partial
state. When it is necessary to perform a full state restore (e.g. after an
execve or signal), the flag is cleared to force a full restore.
Turn off semaphores. Nobody else implements them, and there is lots of
AML out there which does totally absurd things with them, meaning that
if we try to do the right thing we are guaranteed to fail.
Use acpi_EvaluateInteger where possible.
Use FuncName rather than &FuncName when passing function addresses.
Don't evaluate the _REG method when we attach to an address space -
AcpiInstallAddressSpaceHandler does it for us.
acpi_EvaluateInteger.
Use acpi_EvaluateInteger instead of doing things the hard way where
possible.
AcpiSetSystemSleepState (unofficial) becomes AcpiEnterSleepState.
Use the AcpiGbl_FADT pointer rather than searching for the FADT.
to 1GB. A box of mine is running with MAXDSIZ and DFLDSIZ increased
up to 1.5GB.
Wishlist: It would be nice to warn if MAXTSIZ + MAXDSIZ + MAXSSIZ
exceeds VM_MAXUSER_ADDRESS - VM_MINUSER_ADDRESS.
(e.g. ethernet nodes are persistent until you rip out the hardware)
Use this support in the ethernet and sample nodes.
Add some more abstraction on the 'item's so that node and
hook reference counting can be checked easier.
Slight man page correction.
Make pppoe type dependent on ethernet type.
Clean up node shutdown a little.
Move a mutex from MTX_SPIN to MTX_DEF (oops)
Fix small ref-counting bug.
remove warning on one2many type.
incompletely converting simplelocks to mutexes (COM_LOCK() is supposed
to hide the SMP locking internals, but it now depends on mutex interfaces
being visible).
filesystem softdep_process_worklist() is called in a loop until it indicates
that no dependancies remain, but the determination of that fact depends on
there only being one softdep_process_worklist() instance running. It was
possible for the syncer to also be running softdep_process_worklist()
and the pre-existing checks in the code to prevent this were not sufficient
to prevent the race. This patch solves the problem.
Approved-by: mckusick
- Add a note about the special locking semantics used for members such as
p_cred that are read by multiple processes but only written to by the
current process.
- Change p_upages_obj's locking key to note that it is created at fork
and left alone afterwards (the actual pointer, not what it points to.)
- Mark p_intr_nesting_level as being implicitly locked since only curproc
accesses it.
Reviewed by: jake
valid) if BPF is missing.
The netgraph_bpf node forced bpf to be present, reflect that in the
options.
Stop doing a 'count bpf' - we provide stubs.
Since a handful of drivers still refer to "bpf.h", provide a more accurate
indication that the API is present always. (eg: netinet6)
With this flag set malloc() will panic if memory allocation failed.
This usable only in critical places where failed allocation is fatal.
Reviewed by: peter
would *want* to is a different story, but it used to be able to be done
statically. Get rid of #include "loop.h" and struct ifnet loif[NLOOP];
This could be used as an example of how to do this in other drivers,
for example: ccd.
fsyncs, which typically occur during unmounting, will drain all dirty
buffers even if it takes multiple passes to do so. The guarentee was
mangled by the last patch which solved a problem due to -current disabling
interrupts while holding giant (which caused an infinite spin loop waiting for
I/O to complete). -stable does not have either patch, but has a similar
bug in the original spec_fsync() code which is triggered by a bug in the
softupdates umount code, a fix for which will be committed to -current
as soon as Kirk stamps it. Then both solutions will be MFC'd to -stable.
-stable currently suffers from a combination of the softupdates bug and
a small window of opportunity in the original spec_fsync() code, and -stable
also suffers from the spin-loop bug but since interrupts are enabled the
spin resolves itself in a few milliseconds.
folks.
My guess is that reducing the number of tags is just masking the real
problem for the PR submitter. I'll re-open the PR and see if I can work
with the submitter to diagnose the problem.
PR: 21139
machines (duh!). This was one reason why this script broke on
i386. The other being that on i386 sections did not have the
proper alignment. This has been fixed in sys/sys/linker_set.h.
declarations will not be aligned by default.
o Remove the alignment work-around for alpha. Our current alpha
as(1) does not assume alignment after section switching, nor
does the ia64 as(1).
- When used on a 33MHz PCI BUS, the 53C1010-66 revision 0
requires extra clocks to be inserted in data out phase.
Revision 1 is fixed.
- The 53C1010-33 revision 1 requires internal cycles to be
disabled due to possible contentions on IO registers.
Revision 2 is fixed.
Fix:
- The probing of HVD from GPIO3 bit by the driver was reversed.
The driver could misprobe the bus mode of a 825 or 875 chip
that was not previously initialized (no BIOS for example).
The new method is 'flood' (in addition to the old round-robin)
in which incoming packets are sent to more than one outgoing hook.
(I'm not sure what Rogier is using this for but it seems generally useful
and isn't much extra)
Submitted by: Rogier R. Mulhuijzen (drwilco@drwilco.net )
o Use objdump instead of gensetdefs(1) to build the linker sets.
o Allow overriding of nm and objdump in resp. genassym.sh and
gensetdefs.pl for non-native toolchains.
Reviewed by: arch
Perl improvements: Jos Backus <josb@cncdsl.com>, benno
problem is that a mutex lock, prior to this change, is acquired before
the curproc is set to idleproc, so we mess ourselves up by calling
the mutex lock routine with curproc == NULL.
Moving it up after the aps_ready spin-wait has us hopefully setting it
after idleproc is setup.
Solved by: jake (the allmighty) :-)
Move the helper macros from sbuf.h to sbuf.c
Use ints instead of size_ts.
Relax the requirements for sbuf_finish(): it is now possible to finish an
overflowed buffer.
Make sbuf_len() return -1 instead of 0 if the sbuf overflowed.
Requested by: gibbs
while strlcpy() existed, before it got backed out due to an extended
bikeshed argument. Sigh. Back to the old version with the redundant
code to terminate the string. :-(
is going away soon anyways. Instead, don't pass MTX_RECURSE to mtx_init,
so that WITNESS will panic if the driver mutex is recursed on.
- Use MTX_DEF in mtx_init() instead of assuming that it will be 0.
even if mode PS/2 is forced with bootflags. As a matter of fact,
chipsets needs some extra configuration for accessing PS/2 mode
from ECP. The current patch is only relevant for generic chipsets
since specific code is supposed to deal with this during detection.
instead of a trapframe directly. (Requested by bde.)
- Convert the alpha switch_trampoline to call fork_exit() and use the MI
fork_return() instead of child_return().
- Axe child_return().
- Proc locking in a few places.
- faultin() now must be called with the proc lock held.
- Split up swappable() into a couple of tests so that it can be locke in
swapout_procs().
- Use queue macros.
- Update stopevent() to assert that the proc lock is held when it is
held and is not recursed. Note that the STOPEVENT() macro obtains
the proc lock when calling this function.
mtx right now as it makes debugging harder. When we are in optimizing
mode, we can revisit this.
- Fix the KTR trace messages to use %p rather than 0x%p to avoid duplicate
0x's in KTR output.
- During witness_fixup, release Giant so that witness doesn't get confused.
Also, grab all_mtx while walking the list of mutexes.
- Remove w_sleep and w_recurse. Instead, perform checks on mutexes using
the mutex's mtx_flags field.
- Allow debug.witness_ddb and debug.witness_skipspin to be set from the
loader.
- Add Giant to the front of existing order_list entries to help ensure
Giant is always first.
- Add an order entry for the various proc locks. Note that this only
helps keep proc in order mostly as the allproc and proctree mutexes are
only obtained during a lockmgr operation on the specified mutex.
to extract the PC from that to send to addupc_task() so that it can be
called from MI code.
- Remove all traces of have_giant with extreme prejudice and use
mtx_owned(&Giant) instead where appropriate.
- Proc locking.
- P_FOO -> PS_FOO.
- Don't grab Giant just to look in curproc's p_addr during a trap since we
may choose to immediately exit. Instead, delay grabbing Giant a bit
until we actually need it.
- Don't reset 'p' to 'curproc' in syscall() to handle the case of a child
returning from fork1() since children don't return via syscall().
- Remove an XXX comment in ast() that questions the correctness of the
userland check. The code is correct.
- Don't send IPIs for pmap_invalidate_page() or pmap_invalidate_all()
in the UP case.
- Catch up to cpuno -> cpuid.
- Convert some sanity checks that were #ifdef DIAGNOSTIC to KASSERT()'s.
- Rename the per-CPU variable 'cpuno' to 'cpuid'. This was done so that
there is one consistent name across all architectures for a logical
CPU id.
- Remove all traces of IRQ forwarding.
- Add globaldata_register() hook called by globaldata_init() to register
globaldata structures in the cpuid_to_globaldata array.
- Catch up to P_FOO -> PS_FOO.
- Bring across some fixes for forwarded_statclock() from the i386 version
to handle ithreads and idleproc properly.
- Rename addugd_intr_forwarded() to addupc_intr_forwarded() so that it is
the same name on all architectures.
- Set flags in p_sflag instead of calling psignal() from
forward_hardclock().
- Proc locking.
- When we handle an IPI, turn off its bit in the mask of IPI's we are
currently handling so that an IPI doesn't send a CPU into an infinite
loop.
that mutex operations work.
- Enter Giant earlier so we hold it during boot.
- Proc locking.
- Move globaldata_init() into here from mp_machdep.c so that UP kernels
don't depend on mp_machdep.c. Use a callout in the SMP case to register
the boot processor's globaldata in the cpuid_to_globaldata array.
that name as a variable. Use mtx_owned(&Giant) where appropriate
instead.
- Proc locking.
- P_FOO -> PS_FOO.
- Update comments about enable interrupts during trap and why this may be
bad if we trap while holding a spin mutex.
- Don't bother resetting p to curproc in syscall() in case we are the child
returning from fork. The child hasn't returned from fork through syscall
in a while.
- Remove fork_return() as it has been superseded by the MI version.
the alpha mp_machdep.c.
- Proc locking.
- Catch up to the P_FOO -> PS_FOO proc flags changes.
- Stick ap_init()'s prototype with the other prototypes.
- Remove the Xforwardirq IPI.
- Remove unused simplelocks.
- Don't try to psignal() from forward_statclock(), but set the appropriate
signal pending flag in p_sflag instead.
- Add in KTR_SMP tracepoints for various SMP functions. (Brought over
from the alpha port)
- Setup proc0.p_heldmtx, proc0.contested, and curproc earlier so that we
can use mutexes.
- Initialize sched_lock and Giant earlier and enter Giant during init386.
- Use suser(9) instead of checking cr_uid directly.
and is protected by the proc lock. p_sflag is protected by sched_lock
and holds the following flags: PS_INMEM, PS_OWEUPC, PS_PROFIL, PS_SINTR,
PS_TIMEOUT, PS_ALRMPEND, PS_PROFPEND, PS_CVWAITQ, PS_SWAPINREQ, and
PS_SWAPPING.
- p_klist is definitely locked now by the proc lock.
- p_runtime, p_[usi]u are locked by sched_lock.
- Add a new P_KTHREAD flag set for kernel threads created via
kthread_create(9).
- STOPEVENT() only needs the proc lock, it does not need Giant.
- faultin() already checks PS_INMEM, so simplify the check in PHOLD() so
that we only need to grab the proc lock and let faultin() perform the
PS_INMEM check.
- Add a prototype for zpfind().
- Add prototypes for the new fork_exit() and fork_return() MI functions
that manage the fork return path.
- Add a prototype for the MD function userret() so that it can be called
from fork_return().
- Add needed include of <machine/frame.h> in the kernel.
- remove all occurances of FLAG_XXX values and replace with CARD_TYPEP_XXX
- remove sc_flag from isic softc and replace it with sc_cardtyp
remove some left over redundant definitions from isic and i4b_l1.h
remove left over cvs id from i4b cvs repository
an override as a loader settable variable (fxp_iomap). fxp_iomap is
a bitmap of fxp units that should be configured to use PCI I/O space
in stead of PCI Memory space.
Reviewed by: Kees Jan Koster <dutchman@tccn.cs.kun.nl>, dg@freebsd.org
we must also inform the card of this change. Otherwise the sequencer
will traverse a corrupt list of SCBS. The side effects of this problem
were unknown SCBs completing in the qoutfifo or worse yet, panics due
to sequencer interrupts that referenced what, to the kernel, were invalid
SCB ids.
- Fix several bugs in the wait syscall, including freeing the actual
proc start, freeing the args, freeing the prison, and other minor
nits.
- Use appropriate queue(3) macros.
- Use zpfind() instead of walking zombproc ourselves.
- Use proper atomic operations to make the run time initialization
controlled by svr_str_initialized be MP safe.
- Use appropriate queue(3) macros where needed.
available, the error return should be EADDRNOTAVAIL rather than
EAGAIN.
PR: 14181
Submitted by: Dima Dorfman <dima@unixfreak.org>
Reviewed by: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
* This file must be kept synchronized with <sys/timespec.h>.
* It defines a structure which must be a type pun for
* `struct timespec'; this structure is used in header files where
* the ABI uses a `struct timespec' but standards prohibit its
* definition. (Currently only <sys/stat.h>.)
calls returning EACCES instead of EPERM. This patch modifies vaccess()
to return EPERM instead of EACCES if VADMIN is among the requested
rights. This affects functions normally limited to the owners of
a file, such as chmod(), as EPERM is the error indicating that
privilege would allow the operation, rather than a chance in mandatory
or discretionary rights.
Reported by: bde
splimp() -- we need it because dummynet can be invoked by the
bridging code at splimp().
This should cure the pipe "stalls" that several people have been
reporting on -stable while using bridging+dummynet (the problem
would not affect routers using dummynet).
+ configuration: make sure that the NUL at the end of the config
string is properly detected and handled, and the stats passed
up via sysctl properly reflect which interfaces do bridging.
(The whole config support might make good use of some cleanup
in the future).
+ fixed some bugs related to the corruption of multicast and
broadcast packets: make sure that for those packets the entire
IP + ethernet header is in the mbuf, not in a cluster, so
that writes performed in that area by the upper layers do
not affect us.
+ performance: when calling m_pullup, make room for the ethernet header
as well, we are going to add it in right after. Also, change an m_dup
back to m_copypacket. The former is not necessary anymore now, and
it did not help, anyways.
I will do a fast MFC because 95% of this patch is fixing bad bugs
and i doubt anyone would test the fix in CURRENT. Plus the last
two items mostly bring back some code which was already there in 4.0
times.
Initialize rid to 0. This doesn't seem to make any difference
(the driver doesn't care what rid it gets and no-one seems to
check rid's value), but follows standard conventions.
Pass in our device_t to ahc_alloc(). We now use device_T
softc storage, so passing NULL results in a panic.
Set the unit number in our softc so that the driver core
can retrieve it.
ahc_pci.c:
Set the unit number in our softc so that the driver core
can retrieve it.
aic7770.c:
Insert our softc into the list of softcs when initialization
is successful.
aic7xxx.c:
Remove a workaround for an aic7895 bug we will never trigger.
Add additional diagnostic info to ahc_dump_card_state().
Always panic the system if a sequencer assertion fails.
AHC_SCB_BTT is a "flag" not a "feature". Check the right
field in the softc.
Replace a hard coded number with a constant.
Guard against looping forever in ahc_pause_and_flushwork().
A hot eject or card failure may make the intstat register
return 0xFF, so limit the number of interrupts we'll process.
Correct the code in ahc_search_qinfifo() that guarantees that
the sequencer will see an abort collision if the qinfifo is
modified when a DMA is in progress. We now do this fixup
after modifying the queue. This guarantees that the HSCB
we place at the head of the queue is not the same as the
old head. Using "next hscb" (guaranteed not to be the
same as the first SCB) before clearing the queue could free
up the original head hscb to be used during a remove operation
placing it again at the head of the qinfifo.
aic7xxx.h:
Reduce the maximum number of outstanding commands to 253 from
254. To handle our output queue correctly on machines that only
support 32bit stores, we must clear the array 4 bytes at a
time. To avoid colliding with a DMA write from the sequencer,
we must be sure that 4 slots are empty when we write to clear
the queue. This reduces us to 253 SCBs: 1 that just completed
and the known three additional empty slots in the queue that
preceed it. Yahoo was able to force this race on one of their
systems. Interrupts were disabled for such a time that the
entire output queue was filled (254 entries complete without
any processing), and our 32bit write to clear the status clobbered
one entry.
Add a feature tag for devices that are removable.
aic7xxx.reg:
Never use the sequencer interrupt value of 0xF0. We need
to guanrantee that an INTSTAT value of 0xFF can only occur
during card failure or a hot-eject.
Align the busy targets table with the begining of scratch
space. This seems to appease a chip bug in the aic7895.
aic7xxx.seq:
Be sure to disable select-out after a bus free event that occurs
early in a selection. If we don't disable select-out, we will
believe that it is enabled even though a new selection will never
occur.
Move the clearing of SELDI to just before a jump. This appeases
another chip bug of the aic7895.
Make the target mode command loop a bit more efficient.
AHC_SCB_BTT is a "flag" not a "feature". Check the right
field in the softc.
Properly cleanup the last SCB we tested against should we
fail to properly find an SCB for a reselection.
Add some additional sequencer debugging code.
aic7xxx_freebsd.c:
Limit the driver to 253 outstanding commands per adapter.
Guard against overflow in timeout handling.
aic7xxx_inline.h:
AHC_SCB_BTT is a "flag" not a "feature". Check the right
field in the softc.
aic7xxx_pci.c:
Set the removable feature for the apa1480 cardbus and the 29160C
Compact PCI card.
Don't report high byte termination information for narrow cards.
Use a PCI read rather than a questionable delay when fetching/setting
termination settings.
- replace the simplelock in struct vm_zone with a mutex.
- use a proper SLIST rather than a hand-rolled job for the zone list.
- add a subsystem lock that protects the zone list and the statistics
counters.
- merge _zalloc() into zalloc() and _zfree() into zfree(), and
move them below _zget() so there's no need for a prototype.
- add two initialization functions: one which initializes the
subsystem mutex and the zone list, and one that currently doesn't
do anything.
- zap zerror(); use KASSERTs instead.
- dike out half of sysctl_vm_zone(), which was mostly trying to do
manually what the snprintf() call could do better.
Reviewed by: jhb, jasone
inline functions non-inlined. Hide parts of the mutex implementation that
should not be exposed.
Make sure that WITNESS code is not executed during boot until the mutexes
are fully initialized by SI_SUB_MUTEX (the original motivation for this
commit).
Submitted by: peter
MFC'ed i due time. I can't test it under current right now because
netgraph seems to do unethical things with mutexes.
musycc:
Add status per channel.
Reduce printf chattyness
Keep error counters line if_mn does.
Increase descriptor count.
if_mn:
Support experimental unframed E1 lines.
These two drivers should share more code relating to framed channelized
TDM media in general (T1/E1/E3/T3, Sonet). Anyone interested email me.
interrupt threads to run with it always >= 1, so that malloc can
detect M_WAITOK from "interrupt" context. This is also necessary
in order to context switch from sched_ithd() directly.
Reviewed By: peter
initialization until after malloc() is safe to call, then iterate through
all mutexes and complete their initialization.
This change is necessary in order to avoid some circular bootstrapping
dependencies.
for SMP; just use the same ones as UP. These weren't used without
holding Giant anyway, and the routines that use them would have to
be protected from pre-emption to avoid migrating cpus.
parts: isa and pccard. The isa one is known to work with an IBM
EtherJet ISA card. The pccard one isn't known to work because the
EtherJet pccard I purchased recently arrived DOA :-(. I'll commit the
pccard.conf entry when the replacement card arrives.
I plan on MFC this in a week or two.
pre-emptable kernel. For variables of size 4 bytes or less they compile
to a single instruction, which does not allow a process to migrate cpus
in the middle, and get the value for the "wrong" cpu.
calls it rather than obtaining and releasing it a lot in proc_compare.
- Collect all of the data gathering and stick it just after the
proc_compare loop. This way, we only have to grab sched_lock once now
when handling SIGINFO. All the printf's are done after the values are
calculated.
Submitted mostly by: bde
The counters are incremented when a thread goes to sleep and decremented
either when a thread is woken up by another thread or when the sleep
times out. There existed a race where the sleep count could be decremented
twice resulting in an eventual underflow.
Move the decrementing of the "counters" to the thread initiating the sleep
and thus remedy the problem.
appropriate function, rather than doing a horse-and-buggy
acquire. They now take the mutex type as an arg and can be
used with sleep as well as spin mutexes.
clients have been fixed. (So far as I can tell, all of the user-land
clients of <sys/select.h> do so vacuously, in the expectation that select()
might be declared there.)
SIGXCPU signal, and killing of processes that exceed their allowed run
time until they can play nice with sched_lock. Right now they are just
potentital panics waiting to happen. The printf() has bitten several
people.
not hold sched_lock while calling ttyprintf(). If we are on a serial
console, then ttyprintf() will end up getting the sio lock, resulting in
a lock order violation.
Noticed by: des
o 1.111 imp Sync with FreeBSD.
o 1.110 nonaka Add Roland SCP-55
o 1.109 ichiro add NANOSPEED ROOT-RZ2000 WLAN Card
o 1.108 ichiro add EMTAC A2424i 11Mbps WLAN Card
o 1.107 haya Add IO Data CBIDE2 ata interface card.
o 1.106 jhawk s/NULL}/NULL }/
o 1.105 thorpej " " -> "&sp" in two entries, per Rafal Boni.
o 1.104 thorpej Add SMC 2632W. From Rafal Boni, kern/11775.
o 1.103 drochner add IBM microdrive
o 1.102 soren Typo.
o 1.101 hubertf Add ELSA WaveLAN card & a noname clone(?)
o 1.100 toddpw Socket Comm. PC Card Ethernet, and tidy up naming.
o 1.99 msaitoh MELCO LPC2-TX, Telecom Device TCD-HPC100,
MACNICA ME1-JEIDA
o 1.98 imp Sort BAY into numerical order. (already in FreeBSD)
if_vr: handle the case where vr_encap() returns failure: bust out of the
packet sending loop instead of panicking. Also add some missing
newlines to some printf()s.
if_dc: The miibus_read and miibus_write methods keep swapping in and
out of MII mode by fiddling with CSR6 for cards with MII PHYs.
This is a hack to support the original Macronix 98713 card which
has built-in NWAY that uses an MII-like management interface
even though it uses serial transceivers. Conditionalize this
so that we only do this on 98713 chips, since it does bad things
to genuine tulip chips (and maybe other clones).
{kernel,modules}-reinstall.debug rather than {kernel,modules}-reinstall.
Otherwise, the '.debug' portion of the target is lost, and you end up
reinstalling the non debug version instead of the debug version.
This is an odd one. This patch appears to fix a panic related to background
bitmap writes (for FFS), though neither Kirk, Ian, or I can figure out how
B_CLUSTEROK could possibly be set on a bitmap block to cause the clustering
code to improperly cluster with a buffer undergoing a background write.
In anycase, the clustering code is very fragile and this patch helps with
that, as well as possibly fixing a bug Andre was having.
Suggested by: Ian Dowse <iedowse@maths.tcd.ie>
Testing by: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>
All calls to mtx_init() for mutexes that recurse must now include
the MTX_RECURSE bit in the flag argument variable. This change is in
preparation for an upcoming (further) mutex API cleanup.
The witness code will call panic() if a lock is found to recurse but
the MTX_RECURSE bit was not set during the lock's initialization.
The old MTX_RECURSE "state" bit (in mtx_lock) has been renamed to
MTX_RECURSED, which is more appropriate given its meaning.
The following locks have been made "recursive," thus far:
eventhandler, Giant, callout, sched_lock, possibly some others declared
in the architecture-specific code, all of the network card driver locks
in pci/, as well as some other locks in dev/ stuff that I've found to
be recursive.
Reviewed by: jhb
attempt to read memory when siz is 0
- Clarify comments referring to strlcat() usage
PR: 24278, 24295
Submitted by: Tony Finch <dot@dotat.at>
Richard Kettlewell <rjk@greenend.org.uk>
Reviewed by: -audit
active memory maps. This removes the need to change the memory
map from common to attribute every time a packet is sent/received.
This increases performance and decreases cpu load (ping times on
slow machines improve by about 1.5ms).
Move out the old common memory/attrbiute memory hack functions to a
new header file to tidy up the main code. I want to keep them available
for a while.
non-386 atomic_load_acq(). %eax is an input since its value is used in
the cmpxchg instruction, but we don't care what value it is, so setting
it to a specific value is just wasteful. Thus, it is being used without
being initialized as the warning stated, but it is ok for it to be used
because its value isn't important. Thus, we are only sort of lying when
we say it is an output only operand.
- Add "cc" to the clobber list for atomic_load_acq() since the cmpxchgl
changes ZF.
slow enough as it is, without having to constantly check that it really
is an i386 still. It was possible to compile out the conditionals for
faster cpus by leaving out 'I386_CPU', but it was not possible to
unconditionally compile for the i386. You got the runtime checking whether
you wanted it or not. This makes I386_CPU mutually exclusive with the
other cpu types, and tidies things up a little in the process.
Reviewed by: alfred, markm, phk, benno, jlemon, jhb, jake, grog, msmith,
jasone, dcs, des (and a bunch more people who encouraged it)
compiling errors where gcc would run out of registers.
- Add "cc" to the list of clobbers for micro-ops where we perform
instructions that alter %eflags.
- Use xchgl instead of cmpxchgl to release a spin lock. This could allow
for more efficient register allocation as we no longer mandate that %eax
be used.
- Reenable the optimized mutex micro-ops in the non-i386 case.
allocation routines are being called safely. Since we drop our relevant
mbuf mutex and acquire Giant before we call kmem_malloc(), we have
to make sure that this does not pave the way for a fatal lock order
reversal. Check that either Giant is already held (in which case it's safe
to grab it again and recurse on it) or, if Giant is not held, that no
other locks are held before we try to acquire Giant.
Similarily, add a KASSERT valid in the WITNESS case in m_reclaim() to
nail callers who end up in m_reclaim() and hold a lock.
Pointed out by: jhb
we *really* are.
It should be noted that there is a degenerate case where soft tape
location will be lost (not causing a frozen state- but causing
the loss of reporting fileno/blockno)- that's where you backspace
over a filemark- you stop backspacing as soon as you cross the
filemark, but you have no idea what the record number now is because
you have no idea how many records you are into the file you just
backed into. Such is life.
While I'm at it, also pick up residuals from writing filemarks.
PR: 24222
that modules can call.
- Remove the old gcc <= 2.8 versions of the atomic ops.
- Resort the order of some things in the file so that there is only
one #ifdef for KLD_MODULE, and so that all WANT_FUNCTIONS stuff is
moved to the bottom of the file.
- Remove ATOMIC_ACQ_REL() and just use explicit macros instead.
only CCB type but also extra flags- one of which can be "position
updated".
In other changes: Add in a SA_QUIRK_NO_CPAGE quirk so that it's possible
to avoid using a (broken) device's implementation of he DEVICE COMPRESSION
page.
Also do a couple of printout cleanups.
As per some discussion on FreeBSD-scsi, skip doing tape flushing
if we're reading tape logical block location (MTIOCRDSPOS).
(so we can see rapidly whether something was a fabric device but is
now gone).
Add a tag which says what role this adapter should take. It can take
on the value of None, Target, Initiator or Both. None is useful for
warm failover purposes. Remove the ISP_CFG_NOINIT silliness since
a role of "None" does this.
Add a isp_lastmbxcmd tag to store the opcode for the last mailbox
command used.
Module) and FBM (Fibre Buffer Modules). Also remember to clear the
semaphore registers. Tell the RISC processor to not halt on FPM
parity errors.
Throw out the ISP_CFG_NOINIT silliness and instead go to the use of
adapter 'roles' to see whether one completes initialization or not
(mostly for Fibre Channel). The ultimate intent, btw, of all of this
is to have a warm standby adapter for failover reasons. Because
we do roles now, setting of Target Capable Class 3 service parameters
in the ICB for the 2x00 cards reflects from role. Also, in isp_start,
if we're not supporting an initiator role, we bounce outgoing commands
with a Selection Timeout error. Also clean out the TOGGLE_TMODE
goop for FC- there is no toggling of target mode like there is
for parallel SCSI cards.
Do more cleanup with respect to using target ids 0..125 in F-port
topologies. Also keep track of things which *were* fabric devices
so that when you rescan the fabric you can notify the outer layers
when fabric devices go away.
Only force a LOGOUT for fabric devices if they're still logged in
(i.e., you cat their Port Database entry. Clean up the Get All Next
scanning.
Finally, use a new tag in the softc to store the opcode for the
last mailbox command used so we can report which opcode timed
out.
in-core pointers to summary information. An array in this region
(fs_csp) could overflow on filesystems with a very large number of
cylinder groups (~16000 on i386 with 8k blocks). When this happens,
other fields in the superblock get corrupted, and fsck refuses to
check the filesystem.
Solve this problem by replacing the fs_csp array in 'struct fs'
with a single pointer, and add padding to keep the length of the
128-byte region fixed. Update the kernel and userland utilities
to use just this single pointer.
With this change, the kernel no longer makes use of the superblock
fields 'fs_csshift' and 'fs_csmask'. Add a comment to newfs/mkfs.c
to indicate that these fields must be calculated for compatibility
with older kernels.
Reviewed by: mckusick
broken the handling of uncompressed VJ packets. The attached diff should
hopefully fix that.
Submitted by: Thomas Moestl <tmoestl@gmx.net>
Reviewed by: Sergio de Souza Prallon <prallon@tmp.com.br>
time I tinkered around here. Since INTREN is called from the interrupt
critical path now, it should not be too expensive. In this case, we
look at the bits being changed to decide which 8 bit IO port to write to
rather than unconditionally writing to both. I could probably have gone
further and only done the write if the bits actually changed, but that
seemed overkill for the usual case in interrupt threads.
[an outb is rather expensive when it has to cross the ISA bus]
exactly the same functionality via a sysctl, making this feature
a run-time option.
The default is 1(ON), which means that /dev/random device will
NOT block at startup.
setting kern.random.sys.seeded to 0(OFF) will cause /dev/random
to block until the next reseed, at which stage the sysctl
will be changed back to 1(ON).
While I'm here, clean up the sysctls, and make them dynamic.
Reviewed by: des
Tested on Alpha by: obrien
implement memory fences for the 486+. The 386 still uses versions w/o
memory fences as all operations on the 386 are not program ordered.
The 386 versions are not MP safe.
not yet been caught), don't save the config with a null drive
name (which causes the drive to be renamed "plex" on the next
start), put in the text "*invalid*" instead.
This is damage control, not a fix.
Experienced by: peter
Break some long format strings so that they fit in style(9)-sized
lines.
Remove some "outdentation".
while we are copying it to the kinfo_proc structure.
- Test against p_stat to see if we are blocked on a mutex.
- Terminate ki_mtxname with a null char rather than ki_wmesg.
declarations of a variable of the same name. The one in the outer block
was unused and probably just slipped in at one point or another. This
silences a compiler warning.
#include "quad.h"
to:
#include <libkern/quad.h>
as the former breaks under a kernel build.
This change had already been performed on the files that were used in other
kernel builds, however the PowerPC kernel build seems to require some that
weren't being used.
Reviewed by: obrien, peter
all of the hwvol members of struct snd_mixer live in a hwvol_* namespace.
- When changing the mixer device via the hwvol_mixer sysctl, reset the
muted state so that a mute operation on a new device won't try to
unmute the new device with the old device's saved volume.
- When the volume is muted, if a down or up volume request is received,
first restore the saved volume level and then adjust it.
Reviewed by: cg
from a node, but does it via the locking queue, thus ensuring that the
node is locked when it's hook is removed.
Add 'deadnode' and 'deadhook' structures for when a node or hook is
invalidated but not yet freed. (not yet freed)
__FreeBSD_version 500015 can be used to detect their disappearance.
- Move the symbols for SMP_prvspace and lapic from globals.s to
locore.s.
- Remove globals.s with extreme prejudice.
from Traverse Technology and also the Teles PCI-TJ cards both based on the
chipset combination of the Siemens ISAC and the TJNet Tiger300/320 chips.
The itjc/i4b_hdlc.h file will hopefully soon be merged with the file
/usr/src/sys/i4b/layer1/i4b_hdlc.h.
Submitted by: Sergio de Souza Prallon <prallon@tmp.com.br>
enables the driver to work on current (I have not tested the isa part fully,
but I suppose it should work). The patching from jlemon caused a crash at
probe time. This is probably my fault not having added a comment for
"RESET_SOFT" saying: "this resets all!".
Submitted by: Hans Petter Selasky <hselasky@c2i.net>
cause the watchdog to (incorrectly) detect the interface state
going from down to up one second after lmc_ifup() was called,
causing lmc_ifup() to be called again, and resetting everything.
Fix by checking the interface state within lmc_ifup().
Submitted by: Darren Croke <djc@packetdesign.com>
Rewrite lockrange and unlockrange. The lock table is now a fixed
size, so there is no possibility for race conditions when expanding.
The current size (256 locked ranges) should be large enough that it
makes no sense to expand it. To do expansion right would require
quiescing the plex (requiring at least 256 I/O completions), and the
performance implications are horrendous.
Add a mutex per plex for accessing the lock table.
Based on analysis by: tegge
This should eliminate one case of foot shooting .
vinum_scandisk: If a drive in the partition table is downed, free it.
This duplicates code for the compatibility partition, which for some
reason was omitted here.
m_reclaim() and re-acquire it when m_reclaim() returns. This means that
we now call the drain routines without holding the mutex lock and
recursing into it. This was done for mainly two reasons:
(i) Avoid the long recursion; long recursions are typically bad and this
is the case here because we block all other code from freeing mbufs
if they need to. Doing that is kind of counter-productive, since we're
really hoping that someone will free.
(ii) More importantly, avoid a potential lock order reversal. Right now,
not all the locks have been added to our networking code; but
without this change, we're introducing the possibility for deadlock.
Consider for example ip_drain(). We will likely eventually introduce
a lock for ipq there, and so ip_freef() will be called with ipq lock
held. But, ip_freef() calls m_freem() which in turn acquires the
mmbfree lock. Since we were previously calling ip_drain() with mmbfree
held, our lock order would be: mmbfree->ipq->mmbfree. Some other code
may very well lock ipq first and then call ip_freef(). This would
result in the regular lock order, ipq->mmbfree. Clearly, we have
deadlock if one thread acquires the ipq lock and sits waiting for
mmbfree while another thread calling m_reclaim() acquires mmbfree
and sits waiting for the ipq lock.
Also, make sure to add a comment above m_reclaim()'s definition briefly
explaining this. Also document this above the call to m_reclaim() in
m_mballoc_wait().
Suggested and reviewed by: alfred
one memory map. The memory window for the PCIC is identifed by the resource id
for NEWSBUS drivers. pccardd always uses window 0 and rid 0 when setting maps
up. This fix does not affect pccardd's handling of common memory for ed cards.
Reviewed by: imp
be 64 bits wide. The largest known current actual physical implementation
is 40 bits, so BUS_SPACE_MAXADDR should reflect this. It also seems to
me that BUS_SPACE_UNRESTRICTED should b ~0UL, not ~0.
avma1pp_attach_avma1pp, since the former may be called multiple
times and we only want to initialize the mutex once.
Submitted by: Thomas Moestl <tmoestl@gmx.net>
reserved and now allocated TCP flags in incoming packets. This patch
stops overloading those bits in the IP firewall rules, and moves
colliding flags to a seperate field, ipflg. The IPFW userland
management tool, ipfw(8), is updated to reflect this change. New TCP
flags related to ECN are now included in tcp.h for reference, although
we don't currently implement TCP+ECN.
o To use this fix without completely rebuilding, it is sufficient to copy
ip_fw.h and tcp.h into your appropriate include directory, then rebuild
the ipfw kernel module, and ipfw tool, and install both. Note that a
mismatch between module and userland tool will result in incorrect
installation of firewall rules that may have unexpected effects. This
is an MFC candidate, following shakedown. This bug does not appear
to affect ipfilter.
Reviewed by: security-officer, billf
Reported by: Aragon Gouveia <aragon@phat.za.net>
that require us to register our FC4 types of interest. Allow ourselves, in
F-port topologies, to start logging in fabric devices in the target 0..125
range. Change ISPASYNC_PDB_CHANGED (misnamed) to ISPASYNC_LOGGED_INOUT.
Fix (*SMACK*) again some default WWN stuff. This is *really* hard to get
right across all the range of platforms.
hscbs may be traded during error recovery due to the way
we manage the qinfifo. This has the effect of changing the
index to the sense buffer even though the request sense command
references the original buffer. SCBs don't play this swapping
game and so serve as a more consistent reference.
the pipe, then we were corrupting the pipe_zone free list by calling
pipeclose on rpipe twice. NULL out rpipe to avoid this.
Reviewed by: dillon
Reviewed by: iedowse
- add a dma hack similar to the NetBSD one
- change PDQ_OS_MEM{RD,WR} to use readl/writel rather than deref'ing
a 32 bit va.
Note that I did just enough to get this working on alpha. I probably
should have updated it to use busspace, but I was too lazy to navigate
the twisty minefield of ifdefs that make up this driver.
Tested by: wilko (on both x86 and alpha)
Add the entry for the Yano U640MO-03 MO drive. (ifdef-0-ed out for now)
Fix a hack were an original buffer was modified instead of copied
(cmd[] -> (*rcmd)[])
Submitted by: Iwasa Kazmi <kzmi@ca2.so-net.ne.jp>
instead of the requested length. Otherwise all transfers look like 0 byte
transfers to CAM.
Submitted by: Iwasa Kazmi <kzmi@ca2.so-net.ne.jp>
2) Finalise the command in the case of CBI transfers with CCI (command
completion interrupt).
3) Remove a redundant bzero of a buffer.
idea either) in ufs_extattr_rm.
o More completely fill out the local_aio structure when writing out the
zero'd extended attribute in ufs_extattr_rm -- previoulsy, this worked
fine, but probably should not have. This corrects extraneous warnings
about inconsistent inodes following file deletion.
Reviewed by: jedgar
ufs_extattr_rm.
o Make both reporting locations report the function name where the
inconsistency is discovered, as well as the inode number in question.
Reviewed by: jedgar
The pccard_function_init() call creates a bunch of inactive resources
that are persistant and configured on demand. When the child driver
"allocates" a resource it is connected up to one of these. When the
child releases the resource, we should not delete our copy, just
deactivate it again. Otherwise there is nothing to recreate it again
after several probe functions have run and done an alloc/release cycle.
INVARIANTS shows 0xdeadc0de without this.
More work is needed to do a sweep though the pccard_function_disable()
call to actually delete the resources for real. Right now, we leak
memory on eject (at best), so Dont Do That(TM) yet. This affects
16 bit pccards on a cardbus bridge only. This will be fixed soon, but
for now it gets the cards working.
Reviewed by: imp
to match the pccard.conf file. There are more ID's that need adding, but
these seem to be the common ones.
This was committed on an ep0 interface under NEWCARD:
ep0: <3Com 3c589 10Mbps Ethernet> at port 0x300-0x30f irq 9 function 0 config 1 on pccard1
ep0: Ethernet address 00:10:4b:df:48:57
Reviewed by: imp
attribute read--the offset is required to be 0 by an earlier check,
meaning that it will always be within the scope of the attribute data.
This change should have no impact on executed code paths other than
removing the unnecessary check: please report if any new failures
start to occur as a result.
Obtained from: TrustedBSD Project
to conform to style(9), plus one other convention that I use:
o Declare variables at the start of the function, rather than in blocks
when it doesn't help understanding (mine).
o 80 column limit.
o BSD style statement continuation, rather than "gnu" style.
bus to use. We need to set it here.
This fixes the problem where a probe routine establishes and
disestablishes the interrupt and then we get a panic in the probe
routine.
However, we pass the pointer to the interrupt hanlder count to the
parent bus, which writes its own cookie there, so there may be some
problems with that which isn't apparent at the moment.
Commit made from: laptop running NEWCARD with sn driver (which works,
but gets the wrong ethernet address).
o Fix OLDCARD to use the new interface.
o Rename the offsetp argument to deltap to more closely reflect what it
is returning (it returns the delta from the requested value to the actual
value).
o Remove duplicate $FreeBSD$ in pccbb.c
o Allow deltap to be NULL.
o Convert new isa pcic driver and add XXX comments that this function isn't
actually implemented there (which means that NEWCARD pccard stuff won't
work there until it is).
o Revert attempts to make old inferface work in NEWCARD.
Subitted by: peter (Parts of the new version code)
compiled under newcard yet. ep works just fine under newcard with the
missing ID matching code added (not committed yet):
ep0: <3Com 3c589 10Mbps Ethernet> at port 0x300-0x30f irq 9 function 0
config 1 on pccard1
ep0: Ethernet address 00:10:4b:df:48:57
by even a compile of the OLDCARD code, was unapproved by me the keeper
of OLDCARD and broke OLDCARD and the ray driver.
Adjust new code to cope with the older interface.
If the interface changes in the future, it ***MUST*** be cleared by me
so that the OLDCARD impacts taken into account. It code in card_if.m
is used jointly by both OLDCARD and NEWCARD.
gets the cardbus code to compile, and I was successfully able to map
the CIS into high memory and probe/attach a 16 bit pccard.
Jonathan: feel free to replace this with your version if you want -
this is an expedient hack to get things to build and appear to work.
allocation not succeeding.
In this case, make sure the driver doesn't leak any memory by freeing all
necessary buffers; make sure to loop and free all the previously allocated
mbufs in this routine.
Reviewed by: alfred
symbols in globals.s.
PCPU_GET(name) returns the value of the per-cpu variable
PCPU_PTR(name) returns a pointer to the per-cpu variable
PCPU_SET(name, val) sets the value of the per-cpu variable
In general these are not yet used, compatibility macros remain.
Unifdef SMP struct globaldata, this makes variables such as cpuid
available for UP as well.
Rebuilding modules is probably a good idea, but I believe old
modules will still work, as most of the old infrastructure
remains.
- pccbb no longer needs to remember whether a card is inserted.
- pccbb reissues insertion on load of cardbus/pccard modules.
- got rid of unnecessary delays in power functions.
- Cardbus children are no longer deleted if probe/attach fails.
- non-attached child devices are reprobed at driver_added.
* CARD interface to read CIS
- added card_cis_read/card_cis_free interface to read arbitrary CIS
data. This currently is only implemented in cardbus.
* pccard begins to work
- pccard can now use higher memory space (and uses it by default).
- set_memory_offset interface changed.
- fixed ccr access, which was broken at multiple locations.
- implement an interrupt handler - pccard can now share interrupts.
- resource alloc/release/activate/deactivate functions gutted: some
resources are allocated by the bridge before the child device is
probed or attached. Thus the resource "belongs" to the bridge, and
the pccard_*_resource functions need to fudge the owner/rid.
- changed some error conditions to panics to speed debugging.
* Mutex fix - Giant is entered at the beginning of thread
as multi-processor kernels. The old way made it difficult for kernel
modules to be portable between uni-processor and multi-processor
kernels. It is no longer necessary to jump through hoops.
- always load %fs with the private segment on entry to the kernel
- change the type of the self referntial pointer from struct privatespace
to struct globaldata
- make the globaldata symbol have value 0 in all cases, so the symbols
in globals.s are always offsets, not aliases for fields in globaldata
- define the globaldata space used for uniprocessor kernels in C, rather
than assembler
- change the assmebly language accessors to use %fs, add a macro
PCPU_ADDR(member, reg), which loads the register reg with the address
of the per-cpu variable member
- Provide TUNABLE_INT() hooks for ktr_cpumask, ktr_mask, and ktr_verbose
so that they can be set from the loader by their respective sysctl names.
For example, to turn on KTR_INTR and KTR_PROC in ktr_mask, one could
stick 'debug.ktr.mask="0x1200"' in /boot/loader.conf.
This version is functional and is aproaching solid..
notice I said APROACHING. There are many node types I cannot test
I have tested: echo hole ppp socket vjc iface tee bpf async tty
The rest compile and "Look" right. More changes to follow.
DEBUGGING is enabled in this code to help if people have problems.
to supress logging when ARP replies arrive on the wrong interface:
"/kernel: arp: 1.2.3.4 is on dc0 but got reply from 00:00:c5:79:d0:0c on dc1"
the default is to log just to give notice about possibly incorrectly
configured networks.
aic7xxx.h:
First pass at big-endian support in the Core.
Capture state for second channel on TWIN channel adapters
for suspend and resume.
aic7xxx_freebsd.h:
Stubs for endian conversion functions. These will get filled
out once we get an official kernel api for this kind of thing
that is something more elegant and efficient than a bunch of
manual swaps #ifdefed by platform.
aic7xxx_pci.c
Allow the second channel of motherboard aic7896 chips to be attached.
It turns out that the encoding of the subdevice id differs between
PCI cards and MB based controllers and our check to see, via
the subvendor id, if the second channel was "stuffed" always
turned out negative.
the video switch by another. Exactly as VESA does on top of VGA.
It adds linear framebuffer to S3 VESA 1.2 cards.
Obtained from: The original S3 ISA code comes from
Peter Horton <pdh@colonel-panic.com>
o Use 8 space hard tabs
o Eliminate trailing white space (while I'm here, just in a couple of places)
o wrap mostly at 80 columns (printf literal strings being the notable
exception)
o use return (foo) consistantly
o use 0 vs NULL more consistantly
o use queue(3) xxx_FOREACH macros where appropriate (some places used it
before, others didn't).
o use BSD line continuation parameters
Pendants will likely notice minor style(9) violations, but for the
most part the file now looks much much closer to style(9) and is
mostly self-consistant.
Approved in principle by: dfr
Reviewed by: md5 (no changes to the .o)
specific snd_mixer device rather than global across all mixers.
- Add per-mixer mute status and saved mute_level so that the mixer_hwmute()
function can now toggle the mute state when the mute button is pressed.
- Create a dynamic sysctl tree hw.snd.pcmX when a pcm device is registered.
- Move the hw.snd.hwvol_* sysctl's to hw.snd.pcmX.hwvol_* so that they
are now properly device-specific. Eventually when the mixers become
their own devices these sysctl's will move to live under a mixerX tree.
- Change the interface of the hwvol_mixer sysctl so that it reports the
name of the current mixer device instead of the number and is settable
with the name instead of the number.
- Add a new function mixer_hwinit() used to setup the dynamic sysctl's
needed for the hwvol support that can be called by drivers that support
hwvol.
Reviewed by: cg
to the SYSCTL_ADD_FOO() macros is a constant that should be turned into
a string via the pre-processor. Instead, require it to be an explicit
string so that names can be generated on the fly.
- Make some of the char * arguments to sysctl_add_oid() const to quiet
warnings.
'chancount' never got up to equaling 'maxchans'. As a result,
pcm_makelinks() was never called, and one always had to set the sysctl to
get the /dev/mixer and other symlinks generated in the DEVFS case. Instead,
change the test in pcm_addchan() to call pcm_makelinks() after the first
channel is initialized, since the aliases are linked to channel 0.
Reviewed by: cg
the file verifier. The NFS client is supposed to do a SETATTR after a
successful O_EXCL open/create to clean up the attributes. FreeBSD's
client code was generating a SETATTR rpc but was not generating an access
or modification time update within that rpc, leaving the file with a
broken access time that solaris chokes on (and it doesn't look very
nice when you ls -lua under FreeBSD either!). Fixed.
file.
While there fix the layout of function headers (noticable in long headers)
Fix up some style nits. It's Perl and should be written in that style.
Bump __FreeBSD_version to reflect the move.
For the moment, <sys/select.h> includes <sys/selinfo.h> to allow
clients time to catch up.
Changes made in preparation for SUSv2/POSIX <sys/select.h> requirements.
status register rather than 0. Without this, a single hardware volume
event triggers an interrupt storm.
- Implement hardware volume control for the Maestro chips. This version
only handles the case where both channels are adjusted at the same time.
Reviewed by: cg
- The mixer_hwmute() function can be called when a soundcard receives a
mute request.
- The mixer_hwstep() function can be used to adjust the volume of one or
both channels.
- The 'hw.snd.hwvol_step' sysctl determines the amount that mixer_hwstep()
adjusts the volume by on each call.
- The 'hw.snd.hwvol_mixer' sysctl specifies the mixer device to adjust the
volume on for both functions. The values used correspond to the
SOUNDCARD_MIXER_* constants.
want according to the modes set with the ppc(4) flags. Especially, it
should fix some problems with mode detection of parallel chipsets
configured to EPP but which have timing troubles with the drives. In such
a case, the driver should now fall back to slower modes (PS2, NIBBLE).
out: label in psignal() did not grab sched_lock before trying to release
it. Also, the previous version had several cases where it grabbed
sched_lock before jumping to out: unneccessarily, so rework this a bit.
The runfast: and out: labels must be called with sched_lock released, and
the run: label must be called with it held. Appropriate mtx_assert()'s
have been added that should catch any bugs that may still be in this
code.
Noticed by: bde
extension.
Add ability to create a preload disk giving an address and a length
(suggested by imp)
Fix bug relating to very small md(4) devices.
Update md.c copyright to reflect the status of code copied from vn.c.
(noticed by dillon)
all devices are by default known by their 'cooked' name, so
my change was wrong. I thought it was a hangover from old 'block
tape device' support which hasn't worked (if it ever did) since
v6/PWB.
So, the default tape name is now the same as Linux. Far out, man....
