Commit Graph

247 Commits

Author SHA1 Message Date
Konstantin Belousov
dbe66680b0 The CDP_ACTIVE flag is cleared at the beginning of destroy_devl(),
and destroy_devl() drops dev_mtx. The protection against the race
with dev_rel(), introduced in r163328, should be extended to cover
destroy_devl() calls for the children of the destroyed dev.

Reported and tested by:	joerg
MFC after:	1 week
2011-05-18 22:36:58 +00:00
Andrey V. Elsukov
b50a7799b8 Add make_dev_alias_p() function. It is similar to make_dev_alias(),
but it may return an error like make_dev_p() does.

Reviewed by:	kib (previous version)
MFC after:	2 weeks
2011-05-03 18:54:18 +00:00
Hans Petter Selasky
0bad52e1d8 Fix race in devfs by using LIST_FIRST() instead of
LIST_FOREACH_SAFE() when freeing the devfs private
data entries.

Reviewed by:	kib
MFC after:	3 days
Approved by:	thompsa (mentor)
2010-12-11 08:44:10 +00:00
Jaakko Heinonen
ff91cc99dd Add missing curly brackets. By chance, the missing brackets didn't alter
the code behavior.

Submitted by:	Lucius Windschuh
2010-11-07 14:28:01 +00:00
Jaakko Heinonen
68f7a01392 Check the device name validity on device registration.
A new function prep_devname() sanitizes a device name by removing
leading and redundant sequential slashes. The function returns an error
for names which already exist or are considered invalid.

A new flag MAKEDEV_CHECKNAME for make_dev_p(9) and make_dev_credf(9)
indicates that the caller is prepared to handle an error related to the
device name. An invalid name triggers a panic if the flag is not
specified.

Document the MAKEDEV_CHECKNAME flag in the make_dev(9) manual page.

Idea from:	kib
Reviewed by:	kib
2010-10-07 18:00:55 +00:00
Konstantin Belousov
6c5e633cd6 Add "show cdev" ddb command.
In collaboration with:	pho
MFC after:	1 month
2010-08-06 09:44:01 +00:00
Konstantin Belousov
3979450b4c Add new make_dev_p(9) flag MAKEDEV_ETERNAL to inform devfs that created
cdev will never be destroyed. Propagate the flag to devfs vnodes as
VV_ETERNVALDEV. Use the flags to avoid acquiring devmtx and taking a
thread reference on such nodes.

In collaboration with:	pho
MFC after:	1 month
2010-08-06 09:42:15 +00:00
Ed Schouten
2e983ace8f Remove the unit argument from the recently added make_dev_p().
New code that creates character devices shouldn't use device unit
numbers, but only si_drv[12] to hold pointer to per-device data. Make
this function more future proof by removing the unit number argument.

Discussed with:	kib
2010-06-17 08:49:31 +00:00
Jaakko Heinonen
8fa17b7953 Correct the function name in a KASSERT. 2010-06-16 16:02:17 +00:00
Konstantin Belousov
f1bb758d4b Add another variation of make_dev(9), make_dev_p(9), that is allowed
to fail and can return useful error code.

Requested by:	jh
Reviewed by:	imp, jh
MFC after:	3 weeks
2010-06-12 13:22:39 +00:00
Konstantin Belousov
76d43557d8 When make_dev_credf(MAKEDEV_WAITOK) is called, use
devctl_notify_f(M_WAITOK) for devfs notifications.

Suggested by:	jh
Reviewed by:	imp, jh
MFC after:	3 weeks
2010-06-12 13:21:25 +00:00
Konstantin Belousov
d2ba618a63 Add MAKEDEV_NOWAIT flag to make_dev_credf(9), to create a device node
in a no-sleep context. If resource allocation cannot be done without
sleep, make_dev_credf() fails and returns NULL.

Reviewed by:	jh
MFC after:	2 weeks
2010-05-06 19:22:50 +00:00
Konstantin Belousov
cf14146715 Fix several style issues.
Define make_dev_credv() as static to match declaration.

MFC after:	3 days
2010-02-27 15:26:36 +00:00
Robert Noland
cfd7bacef2 Update d_mmap() to accept vm_ooffset_t and vm_memattr_t.
This replaces d_mmap() with the d_mmap2() implementation and also
changes the type of offset to vm_ooffset_t.

Purge d_mmap2().

All driver modules will need to be rebuilt since D_VERSION is also
bumped.

Reviewed by:	jhb@
MFC after:	Not in this lifetime...
2009-12-29 21:51:28 +00:00
Antoine Brodin
13e403fdea (S)LIST_HEAD_INITIALIZER takes a (S)LIST_HEAD as an argument.
Fix some wrong usages.
Note: this does not affect generated binaries as this argument is not used.

PR:		137213
Submitted by:	Eygene Ryabinkin (initial version)
MFC after:	1 month
2009-12-28 22:56:30 +00:00
John Baldwin
2fa8c8d21e Extend the device pager to support different memory attributes on different
pages in an object.
- Add a new variant of d_mmap() currently called d_mmap2() which accepts
  an additional in/out parameter that is the memory attribute to use for
  the requested page.
- A driver either uses d_mmap() or d_mmap2() for all requests but not both.
  The current implementation uses a flag in the cdevsw (D_MMAP2) to indicate
  that the driver provides a d_mmap2() handler instead of d_mmap().  This
  is done to make the change ABI compatible with existing drivers and
  MFC'able to 7 and 8.

Submitted by:	alc
MFC after:	1 month
2009-08-28 14:06:55 +00:00
John Baldwin
64345f0b57 Add an extension to the character device interface that allows character
device drivers to use arbitrary VM objects to satisfy individual mmap()
requests.
- A new d_mmap_single(cdev, &foff, objsize, &object, prot) callback is
  added to cdevsw.  This function is called for each mmap() request.
  If it returns ENODEV, then the mmap() request will fall back to using
  the device's device pager object and d_mmap().  Otherwise, the method
  can return a VM object to satisfy this entire mmap() request via
  *object.  It can also modify the starting offset into this object via
  *foff.  This allows device drivers to use the file offset as a cookie
  to identify specific VM objects.
- vm_mmap_vnode() has been changed to call vm_mmap_cdev() directly when
  mapping V_CHR vnodes.  This avoids duplicating all the cdev mmap
  handling code and simplifies some of vm_mmap_vnode().
- D_VERSION has been bumped to D_VERSION_02.  Older device drivers
  using D_VERSION_01 are still supported.

MFC after:	1 month
2009-06-01 21:32:52 +00:00
Attilio Rao
9995e57b01 Move the M_WAITOK flag in notify() into an M_NOWAIT one in order to match
the behaviour alredy present with the further malloc() call in
devctl_notify().
This fixes a bug in the CAM layer where the camisr handler finished to
call camperiphfree() (and subsequently destroy_dev() resulting in a new
dev notify) while the xpt lock is held.

PR:		kern/130330
Tested by:	Riccardo Torrini <riccardo dot torrini at esaote dot com>
2009-05-21 13:22:07 +00:00
Ed Schouten
6672361085 Remove dead code from devtoname().
In the good old days it was possible to have dev_t's that referred to
nonexistent devices. In these cases devtoname() automatically generated
names. This is no longer possible, so remove this dead code.

Discussed with:	kib
2009-04-15 20:43:12 +00:00
Ed Schouten
bce79dbb29 Remove unneeded variable and casting from newdev().
Remove the `udev' variable, which has a different type than the original
function argument and si_drv0. The `udev' name is also misleading,
because it is not the number returned by dev2udev(). Rename this
argument to `unit'. It is the same number as returned by dev2unit().
2009-04-15 20:15:36 +00:00
Ed Schouten
d7cbfc1b18 Don't use si_drv0 directly.
We should still access si_drv0 using dev2unit(). Also change the
KASSERT() to really print the udev instead of the unit number. I suspect
it's still useful to print the unit number, especially for devices that
use clone lists, so keep the unit number in the panic string.
2009-04-15 20:08:26 +00:00
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