isdn: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by

isdn: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210023.6889-1-wsa+renesas@sang-engineering.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

isdn: cpai: no need to initialise statics to 0

Static variables do not need to be initialised to 0, because compiler
will initialise all uninitialised statics to 0. Thus, remove the
unneeded initial

isdn: cpai: no need to initialise statics to 0

Static variables do not need to be initialised to 0, because compiler
will initialise all uninitialised statics to 0. Thus, remove the
unneeded initializations.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn: cpai: check ctr->cnr to avoid array index out of bound

The cmtp_add_connection() would add a cmtp session to a controller
and run a kernel thread to process cmtp.

__module_get(THIS_MODULE);

isdn: cpai: check ctr->cnr to avoid array index out of bound

The cmtp_add_connection() would add a cmtp session to a controller
and run a kernel thread to process cmtp.

__module_get(THIS_MODULE);
session->task = kthread_run(cmtp_session, session, "kcmtpd_ctr_%d",
session->num);

During this process, the kernel thread would call detach_capi_ctr()
to detach a register controller. if the controller
was not attached yet, detach_capi_ctr() would
trigger an array-index-out-bounds bug.

[ 46.866069][ T6479] UBSAN: array-index-out-of-bounds in
drivers/isdn/capi/kcapi.c:483:21
[ 46.867196][ T6479] index -1 is out of range for type 'capi_ctr *[32]'
[ 46.867982][ T6479] CPU: 1 PID: 6479 Comm: kcmtpd_ctr_0 Not tainted
5.15.0-rc2+ #8
[ 46.869002][ T6479] Hardware name: QEMU Standard PC (i440FX + PIIX,
1996), BIOS 1.14.0-2 04/01/2014
[ 46.870107][ T6479] Call Trace:
[ 46.870473][ T6479] dump_stack_lvl+0x57/0x7d
[ 46.870974][ T6479] ubsan_epilogue+0x5/0x40
[ 46.871458][ T6479] __ubsan_handle_out_of_bounds.cold+0x43/0x48
[ 46.872135][ T6479] detach_capi_ctr+0x64/0xc0
[ 46.872639][ T6479] cmtp_session+0x5c8/0x5d0
[ 46.873131][ T6479] ? __init_waitqueue_head+0x60/0x60
[ 46.873712][ T6479] ? cmtp_add_msgpart+0x120/0x120
[ 46.874256][ T6479] kthread+0x147/0x170
[ 46.874709][ T6479] ? set_kthread_struct+0x40/0x40
[ 46.875248][ T6479] ret_from_fork+0x1f/0x30
[ 46.875773][ T6479]

Signed-off-by: Xiaolong Huang <butterflyhuangxx@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211008065830.305057-1-butterflyhuangxx@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

isdn: capi: fix mismatched prototypes

gcc-11 complains about a prototype declaration that is different
from the function definition:

drivers/isdn/capi/kcapi.c:724:44: error: argument 2 of type ‘u8

isdn: capi: fix mismatched prototypes

gcc-11 complains about a prototype declaration that is different
from the function definition:

drivers/isdn/capi/kcapi.c:724:44: error: argument 2 of type ‘u8 *’ {aka ‘unsigned char *’} declared as a pointer [-Werror=array-parameter=]
724 | u16 capi20_get_manufacturer(u32 contr, u8 *buf)
| ~~~~^~~
In file included from drivers/isdn/capi/kcapi.c:13:
drivers/isdn/capi/kcapi.h:62:43: note: previously declared as an array ‘u8[64]’ {aka ‘unsigned char[64]’}
62 | u16 capi20_get_manufacturer(u32 contr, u8 buf[CAPI_MANUFACTURER_LEN]);
| ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/isdn/capi/kcapi.c:790:38: error: argument 2 of type ‘u8 *’ {aka ‘unsigned char *’} declared as a pointer [-Werror=array-parameter=]
790 | u16 capi20_get_serial(u32 contr, u8 *serial)
| ~~~~^~~~~~
In file included from drivers/isdn/capi/kcapi.c:13:
drivers/isdn/capi/kcapi.h:64:37: note: previously declared as an array ‘u8[8]’ {aka ‘unsigned char[8]’}
64 | u16 capi20_get_serial(u32 contr, u8 serial[CAPI_SERIAL_LEN]);
| ~~~^~~~~~~~~~~~~~~~~~~~~~~

Change the definition to make them match.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn: capi: fix mismatched prototypes

commit 5ee7d4c7fbc9d3119a20b1c77d34003d1f82ac26 upstream.

gcc-11 complains about a prototype declaration that is different
from the function definition:

drive

isdn: capi: fix mismatched prototypes

commit 5ee7d4c7fbc9d3119a20b1c77d34003d1f82ac26 upstream.

gcc-11 complains about a prototype declaration that is different
from the function definition:

drivers/isdn/capi/kcapi.c:724:44: error: argument 2 of type ‘u8 *’ {aka ‘unsigned char *’} declared as a pointer [-Werror=array-parameter=]
724 | u16 capi20_get_manufacturer(u32 contr, u8 *buf)
| ~~~~^~~
In file included from drivers/isdn/capi/kcapi.c:13:
drivers/isdn/capi/kcapi.h:62:43: note: previously declared as an array ‘u8[64]’ {aka ‘unsigned char[64]’}
62 | u16 capi20_get_manufacturer(u32 contr, u8 buf[CAPI_MANUFACTURER_LEN]);
| ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/isdn/capi/kcapi.c:790:38: error: argument 2 of type ‘u8 *’ {aka ‘unsigned char *’} declared as a pointer [-Werror=array-parameter=]
790 | u16 capi20_get_serial(u32 contr, u8 *serial)
| ~~~~^~~~~~
In file included from drivers/isdn/capi/kcapi.c:13:
drivers/isdn/capi/kcapi.h:64:37: note: previously declared as an array ‘u8[8]’ {aka ‘unsigned char[8]’}
64 | u16 capi20_get_serial(u32 contr, u8 serial[CAPI_SERIAL_LEN]);
| ~~~^~~~~~~~~~~~~~~~~~~~~~~

Change the definition to make them match.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

isdn: capi: dead code removal

The staging isdn drivers are gone, and CONFIG_BT_CMTP is now
the only user. This means a lot of the code in the subsystem
has no remaining callers and can be removed.

isdn: capi: dead code removal

The staging isdn drivers are gone, and CONFIG_BT_CMTP is now
the only user. This means a lot of the code in the subsystem
has no remaining callers and can be removed.

Change the capi user space front-end to be part of kernelcapi,
and the combined module to only be compiled if BT_CMTP is
also enabled, then remove the interfaces that have no remaining
callers.

As the notifier list and the capi_drivers list have no callers
outside of kcapi.c, the implementation gets much simpler.

Some definitions from the include/linux/*.h headers are only
needed internally and are moved to kcapi.h.

Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20191210210455.3475361-2-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

isdn: fix kernel-infoleak in capi_unlocked_ioctl

Since capi_ioctl() copies 64 bytes after calling
capi20_get_manufacturer() we need to ensure to not leak
information to user.

BUG: KMSAN: kernel-inf

isdn: fix kernel-infoleak in capi_unlocked_ioctl

Since capi_ioctl() copies 64 bytes after calling
capi20_get_manufacturer() we need to ensure to not leak
information to user.

BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
CPU: 0 PID: 11245 Comm: syz-executor633 Not tainted 4.20.0-rc7+ #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x173/0x1d0 lib/dump_stack.c:113
kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
kmsan_internal_check_memory+0x9d4/0xb00 mm/kmsan/kmsan.c:704
kmsan_copy_to_user+0xab/0xc0 mm/kmsan/kmsan_hooks.c:601
_copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
capi_ioctl include/linux/uaccess.h:177 [inline]
capi_unlocked_ioctl+0x1a0b/0x1bf0 drivers/isdn/capi/capi.c:939
do_vfs_ioctl+0xebd/0x2bf0 fs/ioctl.c:46
ksys_ioctl fs/ioctl.c:713 [inline]
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl+0x1da/0x270 fs/ioctl.c:718
__x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:718
do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x440019
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdd4659fb8 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440019
RDX: 0000000020000080 RSI: 00000000c0044306 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 00000000004018a0
R13: 0000000000401930 R14: 0000000000000000 R15: 0000000000000000

Local variable description: ----data.i@capi_unlocked_ioctl
Variable was created at:
capi_ioctl drivers/isdn/capi/capi.c:747 [inline]
capi_unlocked_ioctl+0x82/0x1bf0 drivers/isdn/capi/capi.c:939
do_vfs_ioctl+0xebd/0x2bf0 fs/ioctl.c:46

Bytes 12-63 of 64 are uninitialized
Memory access of size 64 starts at ffff88807ac5fce8
Data copied to user address 0000000020000080

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Karsten Keil <isdn@linux-pingi.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn: replace ->proc_fops with ->proc_show

And switch to proc_create_single_data.

Signed-off-by: Christoph Hellwig <hch@lst.de>

isdn: kcapi: make capi_version const

Declare this structure as const as it is only used during a copy
operation.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: David S. Miller <da

isdn: kcapi: make capi_version const

Declare this structure as const as it is only used during a copy
operation.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn: kcapi: avoid uninitialized data

gcc-7 points out that the AVMB1_ADDCARD ioctl results in an unintialized
value ending up in the cardnr parameter:

drivers/isdn/capi/kcapi.c: In function 'old_c

isdn: kcapi: avoid uninitialized data

gcc-7 points out that the AVMB1_ADDCARD ioctl results in an unintialized
value ending up in the cardnr parameter:

drivers/isdn/capi/kcapi.c: In function 'old_capi_manufacturer':
drivers/isdn/capi/kcapi.c:1042:24: error: 'cdef.cardnr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cparams.cardnr = cdef.cardnr;

This has been broken since before the start of the git history, so
either the value is not used for anything important, or the ioctl
command doesn't get called in practice.

Setting the cardnr to zero avoids the warning and makes sure
we have consistent behavior.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>

Fix up affected files that include this signal functionality via sched.h.

Acked-by

sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>

Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

show more ...

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PA

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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isdn/capi: correct capi20_manufacturer argument type mismatch

Function capi20_manufacturer() is declared with unsigned int cmd
argument but called with unsigned long.
Fix by correcting the function

isdn/capi: correct capi20_manufacturer argument type mismatch

Function capi20_manufacturer() is declared with unsigned int cmd
argument but called with unsigned long.
Fix by correcting the function prototype since the actual argument
is part of the user visible API.

Spotted with Coverity.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

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isdn/kcapi: fix a small underflow

In get_capi_ctr_by_nr() and get_capi_appl_by_nr() the parameter comes
from skb->data. The current code can underflow to one space before the
start of the array.

T

isdn/kcapi: fix a small underflow

In get_capi_ctr_by_nr() and get_capi_appl_by_nr() the parameter comes
from skb->data. The current code can underflow to one space before the
start of the array.

The sanity check isn't needed in __get_capi_appl_by_nr() but I changed
it to match the others.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn: whitespace coding style cleanup

isdn source code uses a not-current coding style.

Update the coding style used on a per-line basis
so that git diff -w shows only elided blank lines
at EOF.

D

isdn: whitespace coding style cleanup

isdn source code uses a not-current coding style.

Update the coding style used on a per-line basis
so that git diff -w shows only elided blank lines
at EOF.

Done with emacs and some scripts and some typing.

Built x86 allyesconfig.
No detected change in objdump -d or size.

Signed-off-by: Joe Perches <joe@perches.com>

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isdn/capi: make kcapi use a separate workqueue

flush_scheduled_work() is deprecated and will be removed. Because
kcapi uses fire-and-forget type works, it's impossible to flush each
work explicitly

isdn/capi: make kcapi use a separate workqueue

flush_scheduled_work() is deprecated and will be removed. Because
kcapi uses fire-and-forget type works, it's impossible to flush each
work explicitly. Create and use a dedicated workqueue instead.

Please note that with recent workqueue changes, each workqueue doesn't
reserve a lot of resources and using it as a flush domain is fine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kiszka <jan.kiszka@web.de>

show more ...

CAPI: Silence lockdep warning on get_capi_appl_by_nr usage

As long as we hold capi_controller_lock, we can safely access
capi_applications without RCU protection as no one can modify the
application

CAPI: Silence lockdep warning on get_capi_appl_by_nr usage

As long as we hold capi_controller_lock, we can safely access
capi_applications without RCU protection as no one can modify the
application list underneath us. Introduce an RCU-free
__get_capi_appl_by_nr for this purpose. This silences lockdep warnings
on suspicious rcu_dereference usage.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn/kcapi: return -EFAULT on copy_from_user errors

copy_from_user() returns the number of bytes remaining but we should
return -EFAULT here. The error code gets returned to the user. Both
old_cap

isdn/kcapi: return -EFAULT on copy_from_user errors

copy_from_user() returns the number of bytes remaining but we should
return -EFAULT here. The error code gets returned to the user. Both
old_capi_manufacturer() and capi20_manufacturer() had other places
that already returned -EFAULT so this won't break anything.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

isdn/capi: make reset_ctr op truly optional

The CAPI controller operation reset_ctr is marked as optional, and
not all drivers do implement it. Add a check to the kernel CAPI
whether it exists befor

isdn/capi: make reset_ctr op truly optional

The CAPI controller operation reset_ctr is marked as optional, and
not all drivers do implement it. Add a check to the kernel CAPI
whether it exists before trying to call it.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Acked-by: Karsten Keil <isdn@linux-pingi.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when bu

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

show more ...

CAPI: Drop special controller lookup from capi20_put_message

This strange special rule to fall back to controller 1 cannot be derived
from the CAPI specs and looks a lot like it was once dedicated t

CAPI: Drop special controller lookup from capi20_put_message

This strange special rule to fall back to controller 1 cannot be derived
from the CAPI specs and looks a lot like it was once dedicated to some
out-of-tree driver, probably AVM's broken fcdsl2 (FRITZ!Card DSL v2.0).
I found no in-tree user that needs this check, and I'm now taking care
of the fcdsl2. So drop these bits from our stack.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

CAPI: Rework application locking

Drop the application rw-lock in favour of RCU. This synchronizes
capi20_release against capi_ctr_handle_message which may dereference an
application from (soft-)IRQ

CAPI: Rework application locking

Drop the application rw-lock in favour of RCU. This synchronizes
capi20_release against capi_ctr_handle_message which may dereference an
application from (soft-)IRQ context. Any other access to the application
list is now protected by the capi_controller_lock as well. This also
allows to safely inspect applications for /proc dumping by holding
capi_controller_lock.

At this chance, drop some useless release_in_progress checks where we
obtained the application pointer from the list (which becomes NULL on
release_in_progress).

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

CAPI: Rework locking of controller data structures

This patch applies the mutex so far only protecting the controller list
to (almost) all accesses of controller data structures. It also reworks
wai

CAPI: Rework locking of controller data structures

This patch applies the mutex so far only protecting the controller list
to (almost) all accesses of controller data structures. It also reworks
waiting on state changes in old_capi_manufacturer so that it no longer
poll and holds a module reference to the controller owner while waiting
(the latter was partly done already). Modification and checking of the
blocked state remains racy by design, the caller is responsible for
dealing with this.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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CAPI: Rework controller state notifier

Another step towards proper locking: Rework the callback provided to
capidrv for controller state changes. This is so far attached to an
application, which wou

CAPI: Rework controller state notifier

Another step towards proper locking: Rework the callback provided to
capidrv for controller state changes. This is so far attached to an
application, which would require us to hold the corresponding lock
across notification calls.

But there is no direct relation between a controller up/down event and
an application, so let's decouple them and provide a notifier call chain
for those events instead. This notifier chain is first of all used
internally. Here we request the highest priority to unsure that
housekeeping work is done before any other notifications. The chain is
exported via [un]register_capictr_notifier to our only user, capidrv, to
replace the racy and unfixable capi20_set_callback.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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CAPI: Rework capi_ctr_ready/down

This step prepares the application of proper controller locking: Push
all state changing work into the notify handler that are called by
capi_ctr_ready and capi_ctr_

CAPI: Rework capi_ctr_ready/down

This step prepares the application of proper controller locking: Push
all state changing work into the notify handler that are called by
capi_ctr_ready and capi_ctr_down, switch detach_capi_ctr to issue a
synchronous ctr_down. Also ensure that we do not go through any action
if the state did not change.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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