Commit Graph

226 Commits

Author SHA1 Message Date
Konstantin Belousov
125dcf8c7d Extract the no_poll() and vop_nopoll() code into the common routine
poll_no_poll().
Return a poll_no_poll() result from devfs_poll_f() when
filedescriptor does not reference the live cdev, instead of ENXIO.

Noted and tested by:	hps
MFC after:	1 week
2009-03-06 15:35:37 +00:00
Konstantin Belousov
b7a813fc21 Explicitely note that destroy_dev() sleeps.
Requested by:	ed (some time ago), Jaakko Heinonen <jh saunalahti fi>
2008-11-27 16:47:25 +00:00
Ed Schouten
c6ec8c53c5 Move uminor() and umajor() to the same place as userspace minor() and major().
The uminor() and umajor() functions have the same use in kernel space as
the minor() and major() functions in userspace. If we ever get rid of
the minor() function in kernel space, we could decide to just expose
minor() and major() to kernel space, making uminor() and umajor()
redundant.

There are two reasons why we want to have uminor() and umajor() in
<sys/types.h>:

- Having them close together prevents them from diverting. Even though
  it's unlikely the definitions will change, it's a good habit to have
  them at the same place.

- They don't really belong in kern_conf.c. kern_conf.c has been
  liberated from dealing with device major and minor number handling.

The device_ids(9) manpage now lists the wrong #include's, because it
should only list <sys/types.h> now. I'm leaving it as it is now, because
I wonder if we should document them anyway. We're probably better off
documenting minor(3) and major(3).
2008-09-27 13:19:09 +00:00
Ed Schouten
6bfa9a2d66 Replace all calls to minor() with dev2unit().
After I removed all the unit2minor()/minor2unit() calls from the kernel
yesterday, I realised calling minor() everywhere is quite confusing.
Character devices now only have the ability to store a unit number, not
a minor number. Remove the confusion by using dev2unit() everywhere.

This commit could also be considered as a bug fix. A lot of drivers call
minor(), while they should actually be calling dev2unit(). In -CURRENT
this isn't a problem, but it turns out we never had any problem reports
related to that issue in the past. I suspect not many people connect
more than 256 pieces of the same hardware.

Reviewed by:	kib
2008-09-27 08:51:18 +00:00
Ed Schouten
edde874555 Rename the minor' argument of make_dev(9) to unit'.
To prevent any further confusion about device minor and unit numbers,
we'd better just refer to device unit numbers. Many people still think
the numbers we show inside devfs have any relation to the numbers passed
to make_dev(9), which is not the case.

Discussed with:	kib
2008-09-26 14:31:24 +00:00
Ed Schouten
d3ce832719 Remove unit2minor() use from kernel code.
When I changed kern_conf.c three months ago I made device unit numbers
equal to (unneeded) device minor numbers. We used to require
bitshifting, because there were eight bits in the middle that were
reserved for a device major number. Not very long after I turned
dev2unit(), minor(), unit2minor() and minor2unit() into macro's.
The unit2minor() and minor2unit() macro's were no-ops.

We'd better not remove these four macro's from the kernel, because there
is a lot of (external) code that may still depend on them. For now it's
harmless to remove all invocations of unit2minor() and minor2unit().

Reviewed by:	kib
2008-09-26 14:19:52 +00:00
Ed Schouten
bc093719ca Integrate the new MPSAFE TTY layer to the FreeBSD operating system.
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

  The old TTY layer has a driver model that is not abstract enough to
  make it friendly to use. A good example is the output path, where the
  device drivers directly access the output buffers. This means that an
  in-kernel PPP implementation must always convert network buffers into
  TTY buffers.

  If a PPP implementation would be built on top of the new TTY layer
  (still needs a hooks layer, though), it would allow the PPP
  implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

  With the old TTY layer, it isn't entirely safe to destroy TTY's from
  the system. This implementation has a two-step destructing design,
  where the driver first abandons the TTY. After all threads have left
  the TTY, the TTY layer calls a routine in the driver, which can be
  used to free resources (unit numbers, etc).

  The pts(4) driver also implements this feature, which means
  posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

  One of the major improvements is the per-TTY mutex, which is expected
  to improve scalability when compared to the old Giant locking.
  Another change is the unbuffered copying to userspace, which is both
  used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from:		//depot/projects/mpsafetty/...
Approved by:		philip (ex-mentor)
Discussed:		on the lists, at BSDCan, at the DevSummit
Sponsored by:		Snow B.V., the Netherlands
dcons(4) fixed by:	kan
2008-08-20 08:31:58 +00:00
Konstantin Belousov
ae95dc623a Make it atomic for the devfs_populate_loop() to see the setting of
SI_ALIAS flag and initialization of the si_parent when alias is created.
Assert that supplied parent device is not NULL.

Both situations could cause NULL dereference in the
devfs_populate_loop() when creating a symlink for SI_ALIAS'ed device.
Namely, cdp->cdp_c.si_parent may be NULL.

Reported by:	mav
MFC after:	2 weeks
2008-07-11 11:22:19 +00:00
Konstantin Belousov
05427aafc6 Struct cdev is always the member of the struct cdev_priv. When devfs
needed to promote cdev to cdev_priv, the si_priv pointer was followed.

Use member2struct() to calculate address of the wrapping cdev_priv.
Rename si_priv to __si_reserved.

Tested by:	pho
Reviewed by:	ed
MFC after:	2 weeks
2008-06-16 17:34:59 +00:00
Ed Schouten
0f03ce1bb8 Turn dev2unit(), minor(), unit2minor() and minor2unit() into macro's.
Now that we got rid of the minor-to-unit conversion and the constraints
on device minor numbers, we can convert the functions that operate on
minor and unit numbers to simple macro's. The unit2minor() and
minor2unit() macro's are now no-ops.

The ZFS code als defined a macro named `minor'. Change the ZFS code to
use umajor() and uminor() here, as it is the correct approach to do
this. Also add $FreeBSD$ to keep SVN happy.

Approved by:	philip (mentor), pjd
2008-06-12 08:30:54 +00:00
Ed Schouten
29d4cb241b Don't enforce unique device minor number policy anymore.
Except for the case where we use the cloner library (clone_create() and
friends), there is no reason to enforce a unique device minor number
policy. There are various drivers in the source tree that allocate unr
pools and such to provide minor numbers, without using them themselves.

Because we still need to support unique device minor numbers for the
cloner library, introduce a new flag called D_NEEDMINOR. All cdevsw's
that are used in combination with the cloner library should be marked
with this flag to make the cloning work.

This means drivers can now freely use si_drv0 to store their own flags
and state, making it effectively the same as si_drv1 and si_drv2. We
still keep the minor() and dev2unit() routines around to make drivers
happy.

The NTFS code also used the minor number in its hash table. We should
not do this anymore. If the si_drv0 field would be changed, it would no
longer end up in the same list.

Approved by:	philip (mentor)
2008-06-11 18:55:19 +00:00
Ed Schouten
06d425f92e Remove the distinction between device minor and unit numbers.
Even though we got rid of device major numbers some time ago, device
drivers still need to provide unique device minor numbers to make_dev().
These numbers are only used inside the kernel. They are not related to
device major and minor numbers which are visible in devfs. These are
actually based on the inode number of the device.

It would eventually be nice to remove minor numbers entirely, but we
don't want to be too agressive here.

Because the 8-15 bits of the device number field (si_drv0) are still
reserved for the major number, there is no 1:1 mapping of the device
minor and unit numbers. Because this is now unused, remove the
restrictions on these numbers.

The MAXMAJOR definition was actually used for two purposes. It was used
to convert both the userspace and kernelspace device numbers to their
major/minor pair, which is why it is now named UMINORMASK.

minor2unit() and unit2minor() have now become useless. Both minor() and
dev2unit() now serve the same purpose. We should eventually remove some
of them, at least turning them into macro's. If devfs would become
completely minor number unaware, we could consider using si_drv0 directly,
just like si_drv1 and si_drv2.

Approved by:	philip (mentor)
2008-05-29 12:50:46 +00:00
Konstantin Belousov
06fe11294d Assert that si_threadcount > 0 before decrementing it. This helps catching
the improper use of the dev_refthread/dev_relthread.

Tested by:	pho
MFC after:	1 week
2008-05-23 16:38:38 +00:00
Konstantin Belousov
82f4d64035 Implement the per-open file data for the cdev.
The patch does not change the cdevsw KBI. Management of the data is
provided by the functions
int	devfs_set_cdevpriv(void *priv, cdevpriv_dtr_t dtr);
int	devfs_get_cdevpriv(void **datap);
void	devfs_clear_cdevpriv(void);
All of the functions are supposed to be called from the cdevsw method
contexts.

- devfs_set_cdevpriv assigns the priv as private data for the file
  descriptor which is used to initiate currently performed driver
  operation. dtr is the function that will be called when either the
  last refernce to the file goes away, the device is destroyed  or
  devfs_clear_cdevpriv is called.
- devfs_get_cdevpriv is the obvious accessor.
- devfs_clear_cdevpriv allows to clear the private data for the still
  open file.

Implementation keeps the driver-supplied pointers in the struct
cdev_privdata, that is referenced both from the struct file and struct
cdev, and cannot outlive any of the referee.

Man pages will be provided after the KPI stabilizes.

Reviewed by:	jhb
Useful suggestions from:	jeff, antoine
Debugging help and tested by:	pho
MFC after:	1 month
2008-05-21 09:31:44 +00:00
Konstantin Belousov
48504cc25b Add the devctl notifications for the cdev create/destroy events.
Based on the submission by: Andriy Gapon <avg icyb net ua>
MFC after:	2 weeks
2008-05-14 14:29:54 +00:00
Konstantin Belousov
35b450291a Add two missed chunks from the rev. 1.210, for the giant_read() and
giant_ioctl().

PR:	kern/122287
MFC after:	3 days
2008-04-02 11:11:58 +00:00
Konstantin Belousov
aeeb4202df Fix two races in the handling of the d_gianttrick for the D_NEEDGIANT
drivers.

In the giant_XXX wrappers for the device methods of the D_NEEDGIANT
drivers, do not dereference the cdev->si_devsw. It is racing with
the destroy_devl() clearing of the si_devsw. Instead, use the
dev_refthread() and return ENXIO for the destroyed device. [1]

The check for the D_INIT in the prep_cdevsw() was not synchronized with
the call of the fini_cdevsw() in destroy_devl(), that under rapid device
creation/destruction may result in the use of uninitialized cdevsw [2].
Change the protocol for the prep_cdevsw(), requiring it to be called
under dev_mtx, where the check for D_INIT is done.

Do not free the memory allocated for the gianttrick cdevsw while holding
the dev_mtx, put it into the free list to be freed later. Reuse the
d_gianttrick pointer to keep the size and layout of the struct cdevsw
(requested by phk). Free the memory in the dev_unlock_and_free(), and do
all the free after the dev_mtx is dropped (suggested by jhb).

Reported by:	bsdimp + many [1], pho [2]
Reviewed by:	phk, jhb
Tested by:	pho
MFC after:	1 week
2008-03-17 13:17:10 +00:00
Andrew Thompson
22cf347586 Apply a workaround for the unkillable jail problem where some devices created
within the jail are never freed. si_cred is only used by the MAC framework so
make the cred reference conditional on it being compiled in, this is not a fix
and will need to be reviewed for any new consumers of si_cred.

This will quell some user complaint when using jails with a default kernel.

Reviewed by:	rwatson
MFC after:	3 days
2007-12-05 01:22:03 +00:00
Konstantin Belousov
196a7385ac Revert destroy_dev() to the state before destroy_dev_sched() was introduced.
Attempt to spawn destroy_dev_sched() from it causes inadmissible races.

Requested by:	tegge
Approved by:	re (kensmith)
2007-07-05 13:04:59 +00:00
Konstantin Belousov
09828ba947 Since cdev mutex is after system map mutex in global lock order, free()
shall not be called while holding cdev mutex. devfs_inos unrhdr has cdev as
mutex, thus creating this LOR situation.

Postpone calling free() in kern/subr_unit.c:alloc_unr() and nested functions
until the unrhdr mutex is dropped. Save the freed items on the ppfree list
instead, and provide the clean_unrhdrl() and clean_unrhdr() functions to
clean the list.
Call clean_unrhdrl() after devfs_create() calls immediately before
dropping cdev mutex. devfs_create() is the only user of the alloc_unrl()
in the tree.

Reviewed by:	phk
Tested by:	Peter Holm
LOR:	80
Approved by:	re (kensmith)
2007-07-04 06:56:58 +00:00
Konstantin Belousov
9d53363bc8 Rev. 1.204 and 1.205 got an erronous version of destroy_dev() that
calls destroy_dev_sched() with cdev mutex locked. Commit the code
that was actually tested.

Pointy hat to:	kib
Approved by:	re (implicit)
2007-07-03 18:18:30 +00:00
Konstantin Belousov
6f0281937b Automatically detect deadlock condition in destroy_dev(), that is, if
destroy_dev() is called from csw method, and no d_purge driver method is
provided. Transform the direct call to destroy_dev() into destroy_dev_sched().

Reviewed by:	njl (programming interface)
Debugging help and testing by:	Peter Holm
Approved by:	re (kensmith)
2007-07-03 17:43:20 +00:00
Konstantin Belousov
de10ffa527 Since rev. 1.199 of sys/kern/kern_conf.c, the thread that calls
destroy_dev() from d_close() cdev method would self-deadlock.
devfs_close() bump device thread reference counter, and destroy_dev()
sleeps, waiting for si_threadcount to reach zero for cdev without
d_purge method.

destroy_dev_sched() could be used instead from d_close(), to
schedule execution of destroy_dev() in another context. The
destroy_dev_sched_drain() function can be used to drain the scheduled
calls to destroy_dev_sched(). Similarly, drain_dev_clone_events() drains
the events clone to make sure no lingering devices are left after
dev_clone event handler deregistered.

make_dev_credf(MAKEDEV_REF) function should be used from dev_clone
event handlers instead of make_dev()/make_dev_cred() to ensure that created
device has reference counter bumped before cdev mutex is dropped inside
make_dev().

Reviewed by:	tegge (early versions), njl (programming interface)
Debugging help and testing by:	Peter Holm
Approved by:	re (kensmith)
2007-07-03 17:42:37 +00:00
Konstantin Belousov
9bc911d4a2 devfs_free() calls free_unr(), that may sleep.
Postpone call to devfs_free() after cdev mutex is dropped. Reuse
cdp_list link for queuing devices awaiting deletion in the
cdevp_free_list.

Reported by:	Hans Petter Selasky <hselasky c2i net>
Tested by:	Peter Holm
Approved by:	re (kensmith)
MFC after:	2 weeks
2007-06-19 13:19:23 +00:00
Konstantin Belousov
9e223287c0 Revert UF_OPENING workaround for CURRENT.
Change the VOP_OPEN(), vn_open() vnode operation and d_fdopen() cdev operation
argument from being file descriptor index into the pointer to struct file.

Proposed and reviewed by:	jhb
Reviewed by:	daichi (unionfs)
Approved by:	re (kensmith)
2007-05-31 11:51:53 +00:00
Bruce M Simpson
217f71d80c Use int instead of u_int for the 'extra' argument to the
clone_create() KPI.
This fixes a signedness bug in unit number comparisons.

Submitted by:	imp, Landon Fuller
PR:		kern/105228
MFC after:	2 weeks
2007-02-02 22:27:45 +00:00
Konstantin Belousov
1663075c64 Fix the race between devfs_fp_check and devfs_reclaim. Derefence the
vnode' v_rdev and increment the dev threadcount , as well as clear it
(in devfs_reclaim) under the dev_lock().

Reviewed by:	tegge
Approved by:	pjd (mentor)
2006-10-20 07:59:50 +00:00
Tor Egge
e0c33ad529 Wait for thread count to reach zero in destroy_devl() even when no purge
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.
2006-10-13 20:49:24 +00:00
Poul-Henning Kamp
d595182f0b Make the printfs relating to purging threads from a device less intrusive. 2006-05-17 06:37:14 +00:00
Alfred Perlstein
7d7e053c21 Novel idea, don't print a string if it is NULL!
This protects people from loading _really_ old modules, like say from
5.x to a 6.x or 7.x system, like for instance right after an upgrade.
2006-01-12 19:15:14 +00:00
Bjoern A. Zeeb
ba0b6851b4 Minor whitespace cleanup. 2006-01-04 17:40:54 +00:00
John Baldwin
8c4b6380c7 Move the initialization of the devmtx into the mutex_init() function
called during early init before cninit().

Tested on:	i386, alpha, sparc64
Reviewed by:	phk, imp
Reported by:	Divacky Roman xdivac02 at stud dot fit dot vutbr dot cz
MFC after:	1 week
2005-10-18 18:27:44 +00:00
Poul-Henning Kamp
7bbb3a2690 Make sure the clone lists are sorted in the right order.
Explosion triggered by:	pjd
MFC:	3 days
2005-10-01 19:21:03 +00:00
Poul-Henning Kamp
e606a3c63e Rewamp DEVFS internals pretty severely [1].
Give DEVFS a proper inode called struct cdev_priv.  It is important
to keep in mind that this "inode" is shared between all DEVFS
mountpoints, therefore it is protected by the global device mutex.

Link the cdev_priv's into a list, protected by the global device
mutex.  Keep track of each cdev_priv's state with a flag bit and
of references from mountpoints with a dedicated usecount.

Reap the benefits of much improved kernel memory allocator and the
generally better defined device driver APIs to get rid of the tables
of pointers + serial numbers, their overflow tables,  the atomics
to muck about in them and all the trouble that resulted in.

This makes RAM the only limit on how many devices we can have.

The cdev_priv is actually a super struct containing the normal cdev
as the "public" part, and therefore allocation and freeing has moved
to devfs_devs.c from kern_conf.c.

The overall responsibility is (to be) split such that kern/kern_conf.c
is the stuff that deals with drivers and struct cdev and fs/devfs
handles filesystems and struct cdev_priv and their private liason
exposed only in devfs_int.h.

Move the inode number from cdev to cdev_priv and allocate inode
numbers properly with unr.  Local dirents in the mountpoints
(directories, symlinks) allocate inodes from the same pool to
guarantee against overlaps.

Various other fields are going to migrate from cdev to cdev_priv
in the future in order to hide them.  A few fields may migrate
from devfs_dirent to cdev_priv as well.

Protect the DEVFS mountpoint with an sx lock instead of lockmgr,
this lock also protects the directory tree of the mountpoint.

Give each mountpoint a unique integer index, allocated with unr.
Use it into an array of devfs_dirent pointers in each cdev_priv.
Initially the array points to a single element also inside cdev_priv,
but as more devfs instances are mounted, the array is extended with
malloc(9) as necessary when the filesystem populates its directory
tree.

Retire the cdev alias lists, the cdev_priv now know about all the
relevant devfs_dirents (and their vnodes) and devfs_revoke() will
pick them up from there.  We still spelunk into other mountpoints
and fondle their data without 100% good locking.  It may make better
sense to vector the revoke event into the tty code and there do a
destroy_dev/make_dev on the tty's devices, but that's for further
study.

Lots of shuffling of stuff and churn of bits for no good reason[2].

XXX: There is still nothing preventing the dev_clone EVENTHANDLER
from being invoked at the same time in two devfs mountpoints.  It
is not obvious what the best course of action is here.

XXX: comment out an if statement that lost its body, until I can
find out what should go there so it doesn't do damage in the meantime.

XXX: Leave in a few extra malloc types and KASSERTS to help track
down any remaining issues.

Much testing provided by:		Kris
Much confusion caused by (races in):	md(4)

[1] You are not supposed to understand anything past this point.

[2] This line should simplify life for the peanut gallery.
2005-09-19 19:56:48 +00:00
Poul-Henning Kamp
74f46f19aa Retire unused dev_named() function. 2005-09-15 08:01:57 +00:00
Poul-Henning Kamp
1d45c50ec3 Properly un-giant-trick the cdevsw in fini_cdevsw()
Tripped over by:	Huang wen hui <huang@gddsn.org.cn>
2005-08-20 12:13:51 +00:00
Poul-Henning Kamp
516ad423b1 Handle device drivers with D_NEEDGIANT in a way which does not
penalize the 'good' drivers:  Allocate a shadow cdevsw and populate
it with wrapper functions which grab Giant
2005-08-17 08:19:52 +00:00
Poul-Henning Kamp
b3740d656f Remove stale comment. 2005-08-16 19:47:42 +00:00
Poul-Henning Kamp
9c0af1310c Create a new internal .h file to communicate very private stuff
from kern_conf.c to devfs.

For now just two prototypes, more to come.
2005-08-16 19:08:01 +00:00
Robert Watson
d26dd2d99e When devfs cloning takes place, provide access to the credential of the
process that caused the clone event to take place for the device driver
creating the device.  This allows cloned device drivers to adapt the
device node based on security aspects of the process, such as the uid,
gid, and MAC label.

- Add a cred reference to struct cdev, so that when a device node is
  instantiated as a vnode, the cloning credential can be exposed to
  MAC.

- Add make_dev_cred(), a version of make_dev() that additionally
  accepts the credential to stick in the struct cdev.  Implement it and
  make_dev() in terms of a back-end make_dev_credv().

- Add a new event handler, dev_clone_cred, which can be registered to
  receive the credential instead of dev_clone, if desired.

- Modify the MAC entry point mac_create_devfs_device() to accept an
  optional credential pointer (may be NULL), so that MAC policies can
  inspect and act on the label or other elements of the credential
  when initializing the skeleton device protections.

- Modify tty_pty.c to register clone_dev_cred and invoke make_dev_cred(),
  so that the pty clone credential is exposed to the MAC Framework.

While currently primarily focussed on MAC policies, this change is also
a prerequisite for changes to allow ptys to be instantiated with the UID
of the process looking up the pty.  This requires further changes to the
pty driver -- in particular, to immediately recycle pty nodes on last
close so that the credential-related state can be recreated on next
lookup.

Submitted by:	Andrew Reisse <andrew.reisse@sparta.com>
Obtained from:	TrustedBSD Project
Sponsored by:	SPAWAR, SPARTA
MFC after:	1 week
MFC note:	Merge to 6.x, but not 5.x for ABI reasons
2005-07-14 10:22:09 +00:00
Poul-Henning Kamp
9477d73e32 cdev (still) needs per instance uid/gid/mode
Add unlocked version of dev_ref()

Clean up various stuff in sys/conf.h
2005-03-31 10:29:57 +00:00
Poul-Henning Kamp
eb151cb989 Rename dev_ref() to dev_refl() 2005-03-31 06:51:54 +00:00
Poul-Henning Kamp
b3d82c03fc Remove the global cdev hash and use the cdevsw list instead.
Don't remove the now unused element from cdev yet, wait until
we have a better reason to bump the version.

There is now no longer any upper limit on how many device drivers
a FreeBSD kernel can have.
2005-03-29 11:15:54 +00:00
Poul-Henning Kamp
ff7284eeb4 Remove the global cdev hash and use the cdevsw list instead.
Don't remove the now unused element from cdev yet, wait until
we have a better reason to bump the version.
2005-03-29 09:56:21 +00:00
Poul-Henning Kamp
fd5f6f4cf2 Privatize major(). 2005-03-29 08:13:17 +00:00
Poul-Henning Kamp
bde1a9c98b Kill MAJOR_AUTO 2005-03-17 13:37:28 +00:00
Poul-Henning Kamp
800b42bde0 Prepare for the final onslaught on devices:
Move uid/gid/mode from cdev to cdevsw.

Add kind field to use for devd(8) later.

Bump both D_VERSION and __FreeBSD_version
2005-03-17 12:07:00 +00:00
Poul-Henning Kamp
4ba679d6d0 Remove findcdev(). 2005-03-15 12:58:08 +00:00
Poul-Henning Kamp
0a2e49f1f8 Rename cdev->si_udev to cdev->si_drv0 to reflect the new nature of
the field.
2005-03-15 11:33:28 +00:00
Poul-Henning Kamp
b43ab0e378 Try to fix the mess I made of devname, with the minimal subset of the
larger minor/major patch which was posted for testing.
2005-03-10 18:21:34 +00:00