where they will never succeed. Add a stop-gap measure that will at
least eventually timeout the operation instead of retrying it
indefinately.
MFC after: 1 month
Despite of a few cosmetic things like adding ``irritating silly
parentheses'' around all return values, this mainly improves FDC reset
handling by no longer gratuitously resetting the FDC all the time
(which causes it to lose the notion of the current track) but only in
case of errors, and it sanitizes the block and offset calculations in
fdstrategy() and fdstate(). Some additional cleanup added by me, in
particular the large switch in fdstate() now always uses return to
break out, and no branch falls off the end of the switch statement
anymore. Per Bruce's suggestion, removed M_NOWAIT from the malloc()s
to simplify things.
Submitted by: bde (mostly)
destroyed properly (otherwise bad things would happen after a clone
dev had been created, and the module was kldunloaded). Allocated
children that have not successfully probed are being deleted again
(otherwise fd0 and fd1 have always been allocated, even if only
fd0 was acutally present, and fd1 even survived kldunloading the
module).
Still, kldunloading leaves remnants of the previously existing devices
intact. Why doesn't it destroy all the devices? As a consequence,
since dev->descr now points into no longer allocated memory, the
system panics deep inside printf(9) when running devinfo(1) after
kldunloading the module. Ideas sought...
Also, when kldloading the module on a hints-populated isab0, this bus
somehow has already created an fdc0 entry (a dummy) so the load
attempt fails and will register fdc1 instead. What are those dummy
entries for? Loading the module from the bootloader works, and it
can be unloaded an re-loaded then later.
the sector ID.
Based on numerous comments made by Bruce, rewrite a good part of the
old fdformat() function, and merge it with fdreadid() into a single
unified fdmisccmd() function. Various style and a couple of more
serious bugs fixed there.
While i was at it, i also fixed the long-standing "TODO: don't
allocate buffer on stack." in fdcioctl(), fixed a number of style bugs
there, and finally implemented the FD_DEBUG ioctl command that has
been advertised in <sys/fdcio.h> (formerly <machine/ioctl_fd.h>) for
almost seven years now. ;-)
Submitted by: bde (a lot of fixes for fdformat())
a KLD. Still doesn't work well except in the PCMCIA case (now if only
pccardd(8) could load and unload drivers dynamically...). Mainly, it
tries to find fdc0 on the PCI bus for whatever obscure reasons, but i
need someone who understands driver(9) to fix this. However, it's at least
already better than before, and i'm tired of maintaining too many private
changes in my tree, given the large patches bde submitted. :)
Idea of a KLD triggered by: Michael Reifenberger <root@nihil.plaut.de>
by now (except of a compile test), but i believe this to contain no
actual functional changes.
. Fix the copyright of the Regents i accidentally broke in rev 1.197
(although only a very small part of the original driver survived
at all...).
. Bump MAX_CYLINDER since some obscure formats really use more than 80
cylinders.
. Correctly handle BIO_FORMAT which used to be a bitmask but is now a BIO
command of its own.
. Numerous stylistic fixes.
Submitted by: bde
. staticize out_fdc(), there's no longer an ft(4) driver sharing its use
. remove in_fdc(), has been used by ft(4) last time, long since obsoleted
by fd_in()
. move the declaration of fd_clone() to where most of the other function
declarations are
. de-__P()ify fd_clone(), it's been the only _P()ed function in the
entire file
- Replace some very poorly thought out API hacks that should have been
fixed a long while ago.
- Provide some much more flexible search functions (resource_find_*())
- Use strings for storage instead of an outgrowth of the rather
inconvenient temporary ioconf table from config(). We already had a
fallback to using strings before malloc/vm was running anyway.
. remove stale comments and a stale #define (from the old days of ft(4))
. make MAX_SEC_SIZE (used in isa_dmainit()) a #define
. fix a typo in a string
. use 0 as the blocksize in devstat_add_entry(), since the actual blocksize
is unknown (devstat(9) suggests to use 0 in that case)
can be made userland-visible as <dev/ic/...>. Also, those files are
not supposed to contain any bus-specific details at all, so placing
them under .../isa/ has been a misnomer from the beginning.
The files in src/sys/dev/ic/ have been repo-copied from their old
location (this commit is a forced null commit there to record this
message).
. FD_CLRERR clears the error counter, thus re-enables kernel error
printf()s,
. FD_GSTAT obtains the last FDC operation state, if any,
. FDOPT_NOERRLOG (temporarily) turns off kernel printf() floppy
error logging,
. FDOPT_NOERROR makes the kernel ignore an FDC error, thus can
enable the transfer of an erroneous sector to the user application
All options are being cleared on (last) close.
Prime consumer of the last features will be fdread(1), to be committed
shortly.
(FD_CLRERR should be wired into fdcontrol(8), but then fdcontrol(8)
needs a major rewrite anyway.)
other "system" header files.
Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.
Sort sys/*.h includes where possible in affected files.
OK'ed by: bde (with reservations)
cloning infrastructure standard in kern_conf. Modules are now
the same with or without devfs support.
If you need to detect if devfs is present, in modules or elsewhere,
check the integer variable "devfs_present".
This happily removes an ugly hack from kern/vfs_conf.c.
This forces a rename of the eventhandler and the standard clone
helper function.
Include <sys/eventhandler.h> in <sys/conf.h>: it's a helper #include
like <sys/queue.h>
Remove all #includes of opt_devfs.h they no longer matter.
Remove old DEVFS support fields from dev_t.
Make uid, gid & mode members of dev_t and set them in make_dev().
Use correct uid, gid & mode in make_dev in disk minilayer.
Add support for registering alias names for a dev_t using the
new function make_dev_alias(). These will show up as symlinks
in DEVFS.
Use makedev() rather than make_dev() for MFSs magic devices to prevent
DEVFS from noticing this abuse.
Add a field for DEVFS inode number in dev_t.
Add new DEVFS in fs/devfs.
Add devfs cloning to:
disk minilayer (ie: ad(4), sd(4), cd(4) etc etc)
md(4), tun(4), bpf(4), fd(4)
If DEVFS add -d flag to /sbin/inits args to make it mount devfs.
Add commented out DEVFS to GENERIC
<sys/bio.h>.
<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.
Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.
Still a few bogus uses of struct buf to track down.
Repocopy by: peter
not u_long. On i386's with 64-bit longs, returning u_longs indirectly
in (more than) the space reserved for uintptr_t's tended to corrupt the
previous frame pointer in the stack frame, so it was not easy to debug.
The type mismatches are hidden by the bogus cast in DEVMETHOD().
Exceptions:
Vinum untouched. This means that it cannot be compiled.
Greg Lehey is on the case.
CCD not converted yet, casts to struct buf (still safe)
atapi-cd casts to struct buf to examine B_PHYS
(Much of this done by script)
Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.
Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.
Add bio_queue field for struct bio aware disksort.
Address a lot of stylistic issues brought up by bde.
substitute BUF_WRITE(foo) for VOP_BWRITE(foo->b_vp, foo)
substitute BUF_STRATEGY(foo) for VOP_STRATEGY(foo->b_vp, foo)
This patch is machine generated except for the ccd.c and buf.h parts.
field in struct buf: b_iocmd. The b_iocmd is enforced to have
exactly one bit set.
B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.
Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.
Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue. It is likely to write on your disk
where it should have been reading.
This change is a step in the direction towards a stackable BIO capability.
A lot of this patch were machine generated (Thanks to style(9) compliance!)
Vinum users: Greg has not had time to test this yet, be careful.
-current. It doesn't work yet as stable as the 3.x/PAO version of the
driver does, however, i get occasional `FDC direction bit not set' and
other weird messages, but it basically works at least.
The old (defunct) #ifdef FDC_YE stuff has been eliminated completely
now, PCMCIA-FDC specific functions have been implemented differently
where needed.
Unfortunately, due to the fact that the traditional PeeCee FDC with
its funny non-contiguous register space (one register for WD1003
harddisk controllers is interleaved into the FDC register set), and
Peter's subsequent changes involving two different bus space handles
for normal FDCs, the changes required for the Y-E stuff are more
complex than i'd love them to be. I've done my best to keep the logic
for normal FDCs intact.
Since the Y-E FDC seems to lose interrupts after a FDC reset
sometimes, i've also replaced the timeout logic in fd_turnoff() to
generate an artificial pseudo interrupt in case of a timeout while the
drive has still outstanding transfers waiting. This avoids the total
starvation of the driver that could be observed with highly damaged
media under 3.x/PAO. This part of the patch has been revied by bde
previously.
I've fixed a number of occasions where previous commits have been
missing the encapuslation of ISA DMA related functions inside
FDC_NODMA checks.
I've added one call to SET_BCDR() during preparation of the format
floppy operation. Floppy formatting has been totally broken before in
3.x/PAO (garbage ID fields have been written to the medium, causing
`wrong cylinder' errors upon media reading). This is just black
magic, i don't have the slightes idea _why_ this needs to be but just
copied over the hack that has been used by the PAO folks in the normal
read/write case anyway.
The entired device_busy() stuff seems to be pointless to me. In any
case, i had to add device_unbusy() calls symmetrical to the
device_busy() calls, otherwise the PCMCIA floppy driver could never be
deactivated. (As it used to be, it caused a `mark the device busier
and busier' situation.) IMHO, all block device drivers should be
marked busy based on active buffers still waiting for the driver, so
the device_unbusy() calls should probably go to biodone(). Only one
other driver (whose name escapes me at the moment) uses device_busy()
calls at all, so i question the value of all this...
I think this entire `device busy' logic simply doesn't fit for PCMCIA
&al. It cannot be the decision of some piece of kernel software to
declare a device `busy by now, you can't remove it', when the actual
physical power of removing it is the user pulling the card. The
kernel simply has to cope with the removal, however busy the device
might have been by the time of the removal, period. Perhaps a force
flag needs to be added?
Upon inserting the card a second time, i get:
WARNING: "fd" is usurping "fd"'s cdevsw[]
WARNING: "fd" is usurping "fd"'s bmaj
I suspect this is related to the XXX comment at the call to
cdevsw_add(). Does anybody know what the correct way is to cleanup
this?
It seems that the IDE system uses 0x3f6 for itself, which conflicts with
fdc's default 0x3f0-3f7 allocation range. Sigh. Work around this.
Use bus_set_resource() rather than allocating specific areas, it makes
the code a little cleaner.
Based on work by: dfr
o Rename FDC_PCMCIA to FDC_NODMA to allow systems that don't have dma
for floppies.
o Remove all but two FDC_YE ifdefs. They aren't needed.
o Move defines for YE_DATAPORT to fdreg.h.
Not fixed:
o The pccard probe/attach. However, motivated individuals can more
easily add this now.
This is a merge of changes I've had in my tree for a long time. These
fixes were tested on my VAIO with its normal floppy. Please let me
know if I broke anything.
Prodded by: Peter Wemm <peter@freebsd.org>
This is the hack that compensates for when bios vendors "forget" to
include the fdc control (0x3f7) port in their io port mappings. Instead
of accessing ports outside of a range allocated to a handle, simply
allocate the port directly. It even shows up in the probe..
In particular:
- Don't leave resources allocated in the probe routine. Allocate them
during probe and release them. Probe's job is to identify devices only.
- Don't abuse the ivars pointer.. (!). Create real ivars and use the
proper access system. (the bus_read_ivar method)
- Don't add the children until attach() has successfully grabbed the
hardware, otherwise there are potential leaks if attach fails.
5in HD 2 heads, 77 cylinders, 8 sectors/track, 1024 bytes/sector
5/3.5in DD 2 heads, 80 cylinders, 8 sectors/track, 512 bytes/sector
Meanings of the rogrammer-readeble fd name were explained by Brian
Fundakowski Feldman and Peter Wemm in hackers list and NOKUBI
Hirotaka.
Reviewed by: nyan
misdetecting FIFO capabilities, at least on my girlfriend's Thinkpad 755,
the driver doesn't work using the FIFO.
While i was at it, i (partially) fixed option FCC_YE since it would no
longer have compiled at all under -current. I've also made an attempt
to document the device driver flags value (ab-)used internally by this
option.
RELENG_3 candidate, but with a slightly different patch there (will go
to jkh in email).
programming practices. It seems that newer fdc chips have an
alternative way of setting the transfer speed (including high speed
modes for floppy tape) that doesn't use the control register (which
we don't support - we use the old way only). So, they (the BIOS
programmers) sometimes leave out the 0x3f6 control register from
the PnP ports descriptor(!!). "Hey, it works with windows, so
what's the problem?" :-( Anyway, this hack tries to compensate
for that. This was discussed with dfr (who did the pnp attachment).
device_add_child_ordered(). 'ivars' may now be set using the
device_set_ivars() function.
This makes it easier for us to change how arbitrary data structures are
associated with a device_t. Eventually we won't be modifying device_t
to add additional pointers for ivars, softc data etc.
Despite my best efforts I've probably forgotten something so let me know
if this breaks anything. I've been running with this change for months
and its been quite involved actually isolating all the changes from
the rest of the local changes in my tree.
Reviewed by: peter, dfr
Don't use NFDC as an arbitary limit, it is not required and goes against
using PnP fdc devices (eg: when PNPBIOS is turned on, the motherboard
devices (sio, fdc, etc etc) are detected via PnP, not config(8).)
have been there in the first place. A GENERIC kernel shrinks almost 1k.
Add a slightly different safetybelt under nostop for tty drivers.
Add some missing FreeBSD tags
warnings caused by the arg having the wrong type (not const enough).
The arg was also wrong (a full name instead of a short one) for calls
from from subr_diskmbr.c and pc98/diskslice_machdep.c.
a quick think and discussion among various people some form of some of
these changes will probably be recommitted.
The reversion requested was requested by dg while discussions proceed.
PHK has indicated that he can live with this, and it has been agreed
that some form of some of these changes may return shortly after further
discussion.
the highly non-recommended option ALLOW_BDEV_ACCESS is used.
(bdev access is evil because you don't get write errors reported.)
Kill si_bsize_best before it kills Matt :-)
Use the specfs routines rather having cloned copies in devfs.
Diskslice/label code not yet handled.
Vinum, i4b, alpha, pc98 not dealt with (left to respective Maintainers)
Add the correct hook for devfs to kern_conf.c
The net result of this excercise is that a lot less files depends on DEVFS,
and devtoname() gets more sensible output in many cases.
A few drivers had minor additional cleanups performed relating to cdevsw
registration.
A few drivers don't register a cdevsw{} anymore, but only use make_dev().
Introduce BUF_STRATEGY(struct buf *, int flag) macro, and use it throughout.
please see comment in sys/conf.h about the flag argument.
Remove strategy argument from all the diskslice/label/bad144
implementations, it should be found from the dev_t.
Remove bogus and unused strategy1 routines.
Remove open/close arguments from dssize(). Pick them up from dev_t.
Remove unused and unfinished setgeom support from diskslice/label/bad144 code.
- device_print_child() either lets the BUS_PRINT_CHILD
method produce the entire device announcement message or
it prints "foo0: not found\n"
Alter sys/kern/subr_bus.c:bus_generic_print_child() to take on
the previous behavior of device_print_child() (printing the
"foo0: <FooDevice 1.1>" bit of the announce message.)
Provide bus_print_child_header() and bus_print_child_footer()
to actually print the output for bus_generic_print_child().
These functions should be used whenever possible (unless you can
just use bus_generic_print_child())
The BUS_PRINT_CHILD method now returns int instead of void.
Modify everything else that defines or uses a BUS_PRINT_CHILD
method to comply with the above changes.
- Devices are 'on' a bus, not 'at' it.
- If a custom BUS_PRINT_CHILD method does the same thing
as bus_generic_print_child(), use bus_generic_print_child()
- Use device_get_nameunit() instead of both
device_get_name() and device_get_unit()
- All BUS_PRINT_CHILD methods return the number of
characters output.
Reviewed by: dfr, peter
by removing a floppy that as being operated on.
The spagghetti is hardly understandable at all anymore, so i can't
100 % ascertain this is really the Right Thing to do, maybe our new
floppy driver maintainer, Jesus Monroy Jr can do this. :-))
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.
Reformat and initialize correctly all "struct cdevsw".
Initialize the d_maj and d_bmaj fields.
The d_reset field was not removed, although it is never used.
I used a program to do most of this, so all the files now use the
same consistent format. Please keep it that way.
Vinum and i4b not modified, patches emailed to respective authors.
with other reset handling in rev.1.83 but broke it in rev.1.120. The
breakage didn't seem to cause any problems even on the system which had
problems ("extra" interrupts and botched handling thereof) before rev.1.83.
It only affects multi-floppy systems anyway.
Virtualize bdevsw[] from cdevsw. bdevsw() is now an (inline)
function.
Join CDEV_MODULE and BDEV_MODULE to DEV_MODULE (please pay attention
to the order of the cmaj/bmaj arguments!)
Join CDEV_DRIVER_MODULE and BDEV_DRIVER_MODULE to DEV_DRIVER_MODULE
(ditto!)
(Next step will be to convert all bdev dev_t's to cdev dev_t's
before they get to do any damage^H^H^H^H^H^Hwork in the kernel.)
1:
s/suser/suser_xxx/
2:
Add new function: suser(struct proc *), prototyped in <sys/proc.h>.
3:
s/suser_xxx(\([a-zA-Z0-9_]*\)->p_ucred, \&\1->p_acflag)/suser(\1)/
The remaining suser_xxx() calls will be scrutinized and dealt with
later.
There may be some unneeded #include <sys/cred.h>, but they are left
as an exercise for Bruce.
More changes to the suser() API will come along with the "jail" code.
i386 platform boots, it is no longer ISA-centric, and is fully dynamic.
Most old drivers compile and run without modification via 'compatability
shims' to enable a smoother transition. eisa, isapnp and pccard* are
not yet using the new resource manager. Once fully converted, all drivers
will be loadable, including PCI and ISA.
(Some other changes appear to have snuck in, including a port of Soren's
ATA driver to the Alpha. Soren, back this out if you need to.)
This is a checkpoint of work-in-progress, but is quite functional.
The bulk of the work was done over the last few years by Doug Rabson and
Garrett Wollman.
Approved by: core
peripheral drivers can determine where in the devstat(9) list they are
inserted.
This requires recompilation of libdevstat, systat, vmstat, rpc.rstatd, and
any ports that depend on the devstat code, since the size of the devstat
structure has changed. The devstat version number has been incremented as
well to reflect the change.
This sorts devices in the devstat list in "more interesting" to "less
interesting" order. So, for instance, da devices are now more important
than floppy drives, and so will appear before floppy drives in the default
output from systat, iostat, vmstat, etc.
The order of devices is, for now, kept in a central table in devicestat.h.
If individual drivers were able to make a meaningful decision on what
priority they should be at attach time, we could consider splitting the
priority information out into the various drivers. For now, though, they
have no way of knowing that, so it's easier to put them in an easy to find
table.
Also, move the checkversion() call in vmstat(8) to a more logical place.
Thanks to Bruce and David O'Brien for suggestions, for reviewing this, and
for putting up with the long time it has taken me to commit it. Bruce did
object somewhat to the central priority table (he would rather the
priorities be distributed in each driver), so his objection is duly noted
here.
Reviewed by: bde, obrien
buffer had to be left on the head of the queue for [bufq]disksort()
to sort against. This isn't right for devices that can support multiple
active i/o's, and only the fd driver did it. "Fixing" this in rev.1.36
of ufs_disksubr.c broke the fd driver in much the same way as rev.1.52
of <sys/buf.h> broke it (see rev.1.119).
Bug reported and fix tested by: dt
floppy is used on the toshiba Libretto line of subnotebook computers.
It differs from a normal floppy in that you must use PIO rather than
DMA to transfer the data.
To enable this, you must add options "FDC_YE" to your kernel. I don't
have a machine that has a floppy and a pcmcia slot to test to make
sure that this doesn't impact normal floppy units, so I've left this as
an option.
I have ported this to -current and made an attempt to ensure that the
indentation conforms to style(9), aka the bruce filter.
Reviewed by: nate, markm
Submitted by: David Horwitt (dhorwitt@ucsd.edu)
for possible buffer overflow problems. Replaced most sprintf()'s
with snprintf(); for others cases, added terminating NUL bytes where
appropriate, replaced constants like "16" with sizeof(), etc.
These changes include several bug fixes, but most changes are for
maintainability's sake. Any instance where it wasn't "immediately
obvious" that a buffer overflow could not occur was made safer.
Reviewed by: Bruce Evans <bde@zeta.org.au>
Reviewed by: Matthew Dillon <dillon@apollo.backplane.com>
Reviewed by: Mike Spengler <mks@networkcs.com>
- Call isa_dmadone() whenever necessary to stop DMA and/or free bounce
buffers. Undead DMA corrupted the malloc freelist fairly consistently
in the following configuration: SLICE kernel, 2 floppy drives, no disk
in fd0, disk in fd1.
- Don't call fdc_reset() from fd_timeout(). Doing so gave an "extra"
interrupt which was usually misinterpreted as being for completion
of the next FDC command; the interrupt for completion of the next
FDC command was then usually misinterpreted... There were further
complications for interrupts latched by the soft-spl mechanism so
that they were delivered after all the h/w interrupts went away.
This caused at least wrong head settle delays and may be why the
FreeBSD floppy driver seems to munch floppies more than most floppy
drivers. The reset was unnecessary anyway in cases that didn't have
the bug described next, since is was repeated a little later for
the IOTIMEDOUT state. The state machine has complications to handle
resets correctly, so just use it.
- Don't call retrier() from fd_timeout(). The IOTIMEDOUT state needs
to be processed next, and it isn't valid to set to that state if
retrier() has aborted the current transfer. Doing so caused null
pointer panics after the previous bug was fixed.
Improved error handling:
- If an i/o is aborted, arrange to reset in the state machine before
doing the next i/o. New fdc flag for this. This fixes spurious
warnings and lengthy busy-waiting for the next i/o.
- Split STARTRECAL into RESETCOMPLETE and STARTRECAL and only check
for the results from reset if we actually reset. This fixes spurious
warnings for other paths to STARTRECAL. [Oops, it may break reset
handling for motor-off resets.]
Cleanups in fd_timeout():
- Renamed to fd_iotimeout() to make it clearer that it is only used
for i/o.
- Don't handle the bp == 0 case. This case can't happen for i/o.
- Don't check for controller-busy. We know it must be.
- Don't print anything. retrier() already prints too much for normal
errors.
- Fudge the state differently so that the state machine advances
fdc->retry and the status is invalid (perhaps this should fudge a
valid state like the one for WP).
- Style fixes.
controller reports a successful seek, it is very unlikely to report
seeking to a cylinder other than the one requested, but we check for
this, and botched the error handling for the requested_cylinder != 0
case. This error happened when the bug fixed in rev.1.52 of <sys/buf.h>
caused the head of buffer queue to change to one starting on a different
cylnder - the requested cylinder was found, but it wasn't what we
thought we requested. The fix is simply to arrange to reset the state
machine.
Corruption of the buffer queue seems to only have been a problem in the
floppy driver. Other drivers dequeue the head of the queue before doing
physical i/o on it, so the corruption at worse broke the elevator sort
order. Dequeueing breaks it anyway.
interupt level events. This needs a lot of cleanup, but has been working
here for a month or two.. originally needed for CAM integration
but that hasn't happenned yet. The probing state machines for each
handler should be replaced by a more generic state-service. It's
still quite messy in there..
There is only cdevsw (which should be renamed in a later edit to deventry
or something). cdevsw contains the union of what were in both bdevsw an
cdevsw entries. The bdevsw[] table stiff exists and is a second pointer
to the cdevsw entry of the device. it's major is in d_bmaj rather than
d_maj. some cleanup still to happen (e.g. dsopen now gets two pointers
to the same cdevsw struct instead of one to a bdevsw and one to a cdevsw).
rawread()/rawwrite() went away as part of this though it's not strictly
the same patch, just that it involves all the same lines in the drivers.
cdroms no longer have write() entries (they did have rawwrite (?)).
tapes no longer have support for bdev operations.
Reviewed by: Eivind Eklund and Mike Smith
Changes suggested by eivind.
