tty_struct's driver_data cannot be NULL, no need to test for it.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the reference management features of tty_port to look up and drop
again the tty_struct associated with a capiminor.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Properly associate/disassociate a capiminor object with its TTY via the
install/cleanup handlers instead of trying to guess first open and last
close.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Install a reference counter for capiminor objects. Acquire it when
obtaining a capiminor from the array during capinc_tty_open, drop it
when closing the tty again. Another reference is held for the hook-up
with capincci.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
No need to allocate a fixed major for this TTY, both capifs and udev
make this transparent to the user.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Register capiminors dynamically with the TTY core so that udev can make
them show up as the NCCIs appear or disappear. This removes the need to
check if the capiminor requested in capinc_tty_open actually exists.
And this completely obsoletes capifs which will be scheduled for removal
in a later patch.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Return proper error code if tty_register_driver fails. In contrast,
tty_unregister_driver cannot practically fail, so drop that error
handling. Finally, mark capinc_tty_init/exit with __init/__exit.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Using a plain array of pointers simplifies the management of capiminors.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace open-coded NCCI list management with standard mechanisms.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
capi_read still used interruptible_sleep_on, risking to miss a wakeup
this way. Convert it to wait_event_interruptible.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Both capincci_alloc and capiminor_alloc run in non-atomic context,
update their memory allocations accordingly.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename 'ncci_list_mtx' to 'lock', expressing that it now protects a
larger set of capidev members: the NCCI list, ap.applid (ie. the
registration of the application), and modifications of userflags.
We do not need to protect each and every check for ap.applid because,
once an application is registered, it will stay for the whole lifetime
of the device.
Also, there is no need to apply the capidev mutex during release (if
there could be concurrent users, we would crash them anyway by freeing
the device at the end of capi_release).
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fold capidev_alloc and capidev_free into capi_open and capi_release -
there are no other users. Someone pushed a lock_kernel into capi_open.
Drop it, we don't need it. Also remove the useless test from open that
checks for private_data == NULL.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
No need for anything "harder" here (specifically no need for
irqsave...). Also, make the list removal the first operation of
capidev_free to avoid dumping half-released devices via /proc.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the code a bit more readable be providing stub functions for the
!CONFIG_ISDN_CAPI_MIDDLEWARE case. Though a few lines are moved around,
this comes with no functional changes.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The CVS revisions dumped by all CAPI modules are meaningless today. And
that some CAPI module is loaded or removed does not necessarily deserve
a message. Just keep the message of the central module, capi.ko, drop
the rest.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of looking up the dentry of an NCCI node again in
capifs_free_ncci pass the pointer via the capifs user.
This patch also reduces the #ifdef mess in capi.c a bit as far as capifs
was causing it.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert code away from ->read_proc/->write_proc interfaces. Switch to
proc_create()/proc_create_data() which make addition of proc entries
reliable wrt NULL ->proc_fops, NULL ->data and so on.
Problem with ->read_proc et al is described here commit
786d7e1612 "Fix rmmod/read/write races in
/proc entries"
[akpm@linux-foundation.org: CONFIG_PROC_FS=n build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Info values in the 0x00xx range are defined in the CAPI standard
as "Informational, message processed successfully". Therefore a
CONNECT_B3_CONF message with an Info value in that range should
open an NCCI just as with Info==0.
Impact: minor bugfix
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Acked-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
struct tty_operations::proc_fops took it's place and there is one less
create_proc_read_entry() user now!
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove some pointless conditionals before kfree_skb().
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Today's linux-next build (x86_64 allmodconfig) failed like this:
/drivers/char/tty_ioctl.c: In function 'change_termios':
drivers/isdn/capi/capi.c🔢 error: implicit declaration of function 'n_tty_ioctl'
drivers/isdn/gigaset/ser-gigaset.c: In function 'gigaset_tty_ioctl':
drivers/isdn/gigaset/ser-gigaset.c:648: error: implicit declaration of function 'n_tty_ioctl'
Introduced by commit 686b5e4aea05a80e370dc931b7f4a8d03c80da54
("tty-move-canon-specials"). I added the following patch (which may not
be correct).
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (79 commits)
arm: bus_id -> dev_name() and dev_set_name() conversions
sparc64: fix up bus_id changes in sparc core code
3c59x: handle pci_name() being const
MTD: handle pci_name() being const
HP iLO driver
sysdev: Convert the x86 mce tolerant sysdev attribute to generic attribute
sysdev: Add utility functions for simple int/ulong variable sysdev attributes
sysdev: Pass the attribute to the low level sysdev show/store function
driver core: Suppress sysfs warnings for device_rename().
kobject: Transmit return value of call_usermodehelper() to caller
sysfs-rules.txt: reword API stability statement
debugfs: Implement debugfs_remove_recursive()
HOWTO: change email addresses of James in HOWTO
always enable FW_LOADER unless EMBEDDED=y
uio-howto.tmpl: use unique output names
uio-howto.tmpl: use standard copyright/legal markings
sysfs: don't call notify_change
sysdev: fix debugging statements in registration code.
kobject: should use kobject_put() in kset-example
kobject: reorder kobject to save space on 64 bit builds
...
Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
device_create() is race-prone, so use the race-free
device_create_drvdata() instead as device_create() is going away.
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move the line disciplines towards a conventional ->ops arrangement. For
the moment the actual 'tty_ldisc' struct in the tty is kept as part of
the tty struct but this can then be changed if it turns out that when it
all settles down we want to refcount ldiscs separately to the tty.
Pull the ldisc code out of /proc and put it with our ldisc code.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/isdn/capi/kcapi.c:829:30: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:838:27: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:954:17: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:1007:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:1009:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capiutil.c:453:24: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capilib.c:47:30: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:353:29: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:369:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:486:48: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:515:46: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:541:47: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:692:47: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:699:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:704:14: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:943:53: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:948:32: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:969:42: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:989:48: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1026:69: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1028:19: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1061:20: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1529:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1531:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:338:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:758:32: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:880:40: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:407:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:407:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:444:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:1664:61: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:1969:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2294:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2297:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2338:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2341:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capifs.c:192:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capifs.c:194:33: warning: Using plain integer as NULL pointer
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/isdn/capi/capi.c: In function 'handle_minor_send':
drivers/isdn/capi/capi.c:552: warning: cast from pointer to integer of different size
Of course, the code here might actually be buggy, in which case this patch
should not be applied?
Answer:
No this field is ignored inside linux kernel.Yes this is ugly, but it's
the CAPI spec for all OS.
CAPI DATA_B3 Request/Indication CAPI Message has a mandatory field which
represent the 32 bit buffer address of the payload data. In linux the
payload data do not use a sperate buffer, data follows directely after the
CAPI Message in the same skb and we use this assumption inside the drivers,
so we can ignore this field.
Inside the linux CAPI implemetation we never use this field, so it could
also have no value, but since random data in a message is bad as well (e.g.
displayed in CAPI traces) we set is to the most adequate value.
Outside the kernel the capi20 library sets the correct addresses (there is
an optional second field for 64 bit adresses for 64 bit systems, we do not
use here).
Acked-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The CAPI 2.0 interface uses a semaphore as mutex. Use the mutex API instead
of the (binary) semaphore.
Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I think the following patch should go into the kernel, until the ISDN/CAPI
guys create the real fix for this issue.
The issue is a concurrency issue with some internal CAPI data structure
which can crash the kernel.
On my FritzCard DSL with the AVM driver it crashes about once a day without
this workaround patch. With this workaround patch it's rock-stable (at
least on UP, but I don't see why this shouldn't work on SMP as well. But
maybe I'm missing something.)
This workaround is kind of a sledgehammer which inserts a global lock to
wrap around all the critical sections. Of course, this is a scalability
issue, if you have many ISDN/CAPI cards. But it prevents a crash. So I
vote for this fix to get merged, until people come up with a better
solution. Better have a stable kernel that's less scalable, than a
crashing and useless kernel.
This bug is in the kernel since 2.6.15 (at least).
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Kai Germaschewski <kai.germaschewski@gmx.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the grungy swap all the occurrences in the right places patch that
goes with the updates. At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs
If you are a tty driver author converting an out of tree driver the only
impact should be termios->ktermios name changes for the speed/property
setting functions from your upper layers.
If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)
Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia
[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix ->set_termios declaration]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As part of an SMP cleanliness pass over UML, I consted a bunch of
structures in order to not have to document their locking. One of these
structures was a struct tty_operations. In order to const it in UML
without introducing compiler complaints, the declaration of
tty_set_operations needs to be changed, and then all of its callers need to
be fixed.
This patch declares all struct tty_operations in the tree as const. In all
cases, they are static and used only as input to tty_set_operations. As an
extra check, I ran an i386 allyesconfig build which produced no extra
warnings.
53 drivers are affected. I checked the history of a bunch of them, and in
most cases, there have been only a handful of maintenance changes in the
last six months. serial_core.c was the busiest one that I looked at.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I am getting more or less reproducible crashes from the CAPI subsystem
using the fcdsl driver:
Unable to handle kernel NULL pointer dereference at virtual address 00000010
printing eip:
c39bbca4
*pde = 00000000
Oops: 0000 [#1]
Modules linked in: netconsole capi capifs 3c59x mii fcdsl kernelcapi uhci_hcd usbcore ide_cd cdrom
CPU: 0
EIP: 0060:[<c39bbca4>] Tainted: P VLI
EFLAGS: 00010202 (2.6.16.11 #3)
EIP is at handle_minor_send+0x17a/0x241 [capi]
eax: c24abbc0 ebx: c0b4c980 ecx: 00000010 edx: 00000010
esi: c1679140 edi: c2783016 ebp: 0000c28d esp: c0327e24
ds: 007b es: 007b ss: 0068
Process swapper (pid: 0, threadinfo=c0326000 task=c02e1300)
Stack: <0>000005b4 c1679180 00000000 c28d0000 c1ce04e0 c2f69654 c221604e c1679140
c39bc19a 00000038 c20c0400 c075c560 c1f2f800 00000000 c01dc9b5 c1e96a40
c075c560 c2ed64c0 c1e96a40 c01dcd3b c2fb94e8 c075c560 c0327f00 c1e96a40
Call Trace:
[<c39bc19a>] capinc_tty_write+0xda/0xf3 [capi]
[<c01dc9b5>] ppp_sync_push+0x52/0xfe
[<c01dcd3b>] ppp_sync_send+0x1f5/0x204
[<c01d9bc1>] ppp_push+0x3e/0x9c
[<c01dacd4>] ppp_xmit_process+0x422/0x4cc
[<c01daf3f>] ppp_start_xmit+0x1c1/0x1f6
[<c0213ea5>] qdisc_restart+0xa7/0x135
[<c020b112>] dev_queue_xmit+0xba/0x19e
[<c0223f69>] ip_output+0x1eb/0x236
[<c0220907>] ip_forward+0x1c1/0x21a
[<c021fa6c>] ip_rcv+0x38e/0x3ea
[<c020b4c2>] netif_receive_skb+0x166/0x195
[<c020b55e>] process_backlog+0x6d/0xd2
[<c020a30f>] net_rx_action+0x6a/0xff
[<c0112909>] __do_softirq+0x35/0x7d
[<c0112973>] do_softirq+0x22/0x26
[<c0103a9d>] do_IRQ+0x1e/0x25
[<c010255a>] common_interrupt+0x1a/0x20
[<c01013c5>] default_idle+0x2b/0x53
[<c0101426>] cpu_idle+0x39/0x4e
[<c0328386>] start_kernel+0x20b/0x20d
Code: c0 e8 b3 b6 77 fc 85 c0 75 10 68 d8 c8 9b c3 e8 82 3d 75 fc 8b 43 60 5a eb 50 8d 56 50 c7 00 00 00 00 00 66 89 68 04 eb 02 89
ca <8b> 0a 85 c9 75 f8 89 02 89 da ff 46 54 8b 46 10 e8 30 79 fd ff
<0>Kernel panic - not syncing: Fatal exception in interrupt
That oops took me to the "ackqueue" implementation in capi.c. The crash
occured in capincci_add_ack() (auto-inlined by the compiler).
I read the code a bit and finally decided to replace the custom linked list
implementation (struct capiminor->ackqueue) by a struct list_head. That
did not solve the crash, but produced the following interresting oops:
Unable to handle kernel paging request at virtual address 00200200
printing eip:
c39bb1f5
*pde = 00000000
Oops: 0002 [#1]
Modules linked in: netconsole capi capifs 3c59x mii fcdsl kernelcapi uhci_hcd usbcore ide_cd cdrom
CPU: 0
EIP: 0060:[<c39bb1f5>] Tainted: P VLI
EFLAGS: 00010246 (2.6.16.11 #3)
EIP is at capiminor_del_ack+0x18/0x49 [capi]
eax: 00200200 ebx: c18d41a0 ecx: c1385620 edx: 00100100
esi: 0000d147 edi: 00001103 ebp: 0000d147 esp: c1093f3c
ds: 007b es: 007b ss: 0068
Process events/0 (pid: 3, threadinfo=c1092000 task=c1089030)
Stack: <0>c2a17580 c18d41a0 c39bbd16 00000038 c18d41e0 00000000 d147c640 c29e0b68
c29e0b90 00000212 c29e0b68 c39932b2 c29e0bb0 c10736a0 c0119ef0 c399326c
c10736a8 c10736a0 c10736b0 c0119f93 c011a06e 00000001 00000000 00000000
Call Trace:
[<c39bbd16>] handle_minor_send+0x1af/0x241 [capi]
[<c39932b2>] recv_handler+0x46/0x5f [kernelcapi]
[<c0119ef0>] run_workqueue+0x5e/0x8d
[<c399326c>] recv_handler+0x0/0x5f [kernelcapi]
[<c0119f93>] worker_thread+0x0/0x10b
[<c011a06e>] worker_thread+0xdb/0x10b
[<c010c998>] default_wake_function+0x0/0xc
[<c011c399>] kthread+0x90/0xbc
[<c011c309>] kthread+0x0/0xbc
[<c0100a65>] kernel_thread_helper+0x5/0xb
Code: 7e 02 89 ee 89 f0 5a f7 d0 c1 f8 1f 5b 21 f0 5e 5f 5d c3 56 53 8b 48 50 89 d6 89 c3 8b 11 eb 2f 66 39 71 08 75 25 8b 41 04 8b 11 <89> 10 89 42 04 c7 01 00 01 10 00 89 c8 c7 41 04 00 02 20 00 e8
The interresting part of it is the "virtual address 00200200", which is
LIST_POISON2. I thought about some race condition, but as this is an UP
system, it leads to questions on how it can happen. If we look at EFLAGS:
00010202, we see that interrupts are enabled at the time of the crash
(eflags & 0x200).
Finally, I don't understand all the capi code, but I think that
handle_minor_send() is racing somehow against capi_recv_message(), which
call both capiminor_del_ack(). So if an IRQ occurs in the middle of
capiminor_del_ack() and another instance of it is invoked, it leads to
linked list corruption.
I came up with the following patch. With this, I could not reproduce the
crash anymore. Clearly, this is not the correct fix for the issue. As this
seems to be some locking issue, there might be more locking issues in that
code. For example, doesn't the whole struct capiminor have to be locked
somehow?
Cc: Carsten Paeth <calle@calle.de>
Cc: Kai Germaschewski <kai.germaschewski@gmx.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I am having the bug FATAL: Error inserting capi ([..]/capi.ko): Device or
resource busy when I try to reload capi after loading it. in dmesg:
capi20: unable to get major 68
Fix the issue which is caused by setting the major to zero when registering
the chrdev succeeded.
(akpm: this means that we can again not use `major=0' (dynamic major
allocation) for this driver).
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If the user specified `major=0' (odd thing to do), capi.c will use dynamic
allocation. We need to pick up that major for subsequent unregister_chrdev().
Acked-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.
This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.
When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.
For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).
Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.
The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.
I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.
Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real. That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.
Description:
tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification]. It
does now also return the number of chars inserted
There are also
tty_buffer_request_room(tty, len)
which asks for a buffer block of the length requested and returns the space
found. This improves efficiency with hardware that knows how much to
transfer.
and tty_insert_flip_string_flags(tty, str, flags, len)
to insert a string of characters and flags
For a smart interface the usual code is
len = tty_request_buffer_room(tty, amount_hardware_says);
tty_insert_flip_string(tty, buffer_from_card, len);
More description!
At the moment tty buffers are attached directly to the tty. This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)
I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers. This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.
So far so good. Lots of drivers reference tty->flip.*. Several of them also
call directly and unsafely into function pointers it provides. This will all
break. Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.
At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say
int tty_buffer_request_room(tty, size)
Try and ensure at least size bytes are available, returns actual room (may be
zero). At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative. (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space. The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.
int tty_insert_flip_char(tty, ch, flag)
As before insert a character if there is room. Now returns 1 for success, 0
for failure.
int tty_insert_flip_string(tty, str, len)
Insert a block of non error characters. Returns the number inserted.
int tty_prepare_flip_string(tty, strptr, len)
Adjust the buffer to allow len characters to be added. Returns a buffer
pointer in strptr and the length available. This allows for hardware that
needs to use functions like insl or mencpy_fromio.
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
