dev_t. The dev_depends(dev_t, dev_t) function is for tying them
to each other.
When destroy_dev() is called on a dev_t, all dev_t's depending
on it will also be destroyed (depth first order).
Rewrite the make_dev_alias() to use this dependency facility.
kern/subr_disk.c:
Make the disk mini-layer use dependencies to make sure all
relevant dev_t's are removed when the disk disappears.
Make the disk mini-layer precreate some magic sub devices
which the disk/slice/label code expects to be there.
kern/subr_disklabel.c:
Remove some now unneeded variables.
kern/subr_diskmbr.c:
Remove some ancient, commented out code.
kern/subr_diskslice.c:
Minor cleanup. Use name from dev_t instead of dsname()
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
insertion of a CF card, for random values of N > 1. With these fixes,
I've been able to do 100 insert/remove of the cards w/o a crash with
lots of system activity going on that in the past would help trigger
the crash.
The problem:
FreeBSD creates dev_t's on the fly as they are needed and never
destroys them. These dev_t's point to a struct disk that is used for
housekeeping on the disk. When a device goes away, the struct disk
pointer becomes a dangling pointer. Sometimes when the device comes
back, the pointer will point to the new struct disk (in which case the
insertion will work). Other times it won't (especially if any length
of time has passed, since it is dependent on memory returned from
malloc).
The Fix:
There is one of these dev_t's that is always correct. The
device for the WHOLE_DISK_SLICE is always right. It gets set at
create_disk() time. So, the fix is to spend a little CPU time and
lookup the WHOLE_DISK_SLICE dev_t and use the si_disk from that in
preference to the one that's in the device asking to do the I/O. In
addition, we change the test of si_disk == NULL meaning that the dev
needed to inherit properties from the pdev to dev->si_disk !=
pdev->si_disk. This test is a little stronger than the previous test,
but can sometimes be fooled into not inheriting. However, the results
of this fooling are that the old values will be used, which will
generally always be the same as before. si_drv[12] are the only
values that are copied that might pose a problem. They tend to change
as the si_disk field would change, so it is a hole, but it is a small
hole.
One could correctly argue that one should replace much of this code
with something much much better. I would be on the pro side of that
argument.
Reviewed by: phk (who also ported the original patch to current)
Sponsored by: Timing Solutions
need this RSN.
Remove a pointless warning in the root device locating code.
Remove the "wd" compatibility name from the "ad" driver.
WARNING: If you have not updated to use /dev/wd* in your /etc/fstab
and modern bootblocks, it would be a very good idea to do so BEFORE
you upgrade your kernel.
<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
in struct bio. Eventually, bio_offset will probably obsolete the
bio_blkno and bio_pblkno fields.
Remove the special hack in atapi-cd.c to determine of bio_offset was valid.
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.
was needed to make attach/detach of devices work, which is
needed for the PCCARD support.
(PCCARD support is still not working though, more to come on that)
Support the CMD646 chip which is used on many alphas, sadly only
in WDMA2 mode, as the silicon is broken beyond belief for UDMA modes.
Lots of cosmetic fixes here and there.
Sorry for the size of this megapatchfromhell but it was not
possible otherwise...
newbus patches based on work from: dfr (Doug Rabson)
around meant that the higher level close routine never gets called.
(phk is on the road; this is a quick fix to get things working and may need
more polish)
