tty: tty_driver: document both {,__}tty_alloc_driver() properly

__tty_alloc_driver()'s kernel-doc needed some care: describe the return
value using the standard "Returns:", and use the new enum tty_

tty: tty_driver: document both {,__}tty_alloc_driver() properly

__tty_alloc_driver()'s kernel-doc needed some care: describe the return
value using the standard "Returns:", and use the new enum tty_driver_flag
for @flags.

Then, the tty_alloc_driver() macro was undocumented, but referenced many
times in the docs. Copy the docs from the above (except the @owner
parameter, obviously).

Signed-off-by: Jiri Slaby (SUSE) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysc

treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.

Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.

Created this by running an spatch followed by a sed command:
Spatch:
virtual patch

@
depends on !(file in "net")
disable optional_qualifier
@

identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@

+ const
struct ctl_table table_name [] = { ... };

sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c

Reviewed-by: Song Liu <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]> # for kernel/trace/
Reviewed-by: Martin K. Petersen <[email protected]> # SCSI
Reviewed-by: Darrick J. Wong <[email protected]> # xfs
Acked-by: Jani Nikula <[email protected]>
Acked-by: Corey Minyard <[email protected]>
Acked-by: Wei Liu <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Reviewed-by: Bill O'Donnell <[email protected]>
Acked-by: Baoquan He <[email protected]>
Acked-by: Ashutosh Dixit <[email protected]>
Acked-by: Anna Schumaker <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

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drivers: remove get_task_comm() and print task comm directly

Since task->comm is guaranteed to be NUL-terminated, we can print it
directly without the need to copy it into a separate buffer. This
s

drivers: remove get_task_comm() and print task comm directly

Since task->comm is guaranteed to be NUL-terminated, we can print it
directly without the need to copy it into a separate buffer. This
simplifies the code and avoids unnecessary operations.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yafang Shao <[email protected]>
Reviewed-by: Jiri Slaby <[email protected]> (For tty)
Reviewed-by: Lyude Paul <[email protected]> (For nouveau)
Cc: Oded Gabbay <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Simona Vetter <[email protected]>
Cc: Karol Herbst <[email protected]>
Cc: Lyude Paul <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: "André Almeida" <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Borislav Petkov (AMD) <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Morris <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul Moore <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vineet Gupta <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

tty: Make sysctl table const

Since commit 7abc9b53bd51 ("sysctl: allow registration of const struct
ctl_table"), the sysctl registration API allows for struct ctl_table to be
in read-only memory. Mo

tty: Make sysctl table const

Since commit 7abc9b53bd51 ("sysctl: allow registration of const struct
ctl_table"), the sysctl registration API allows for struct ctl_table to be
in read-only memory. Move tty_table to be declared at build time, instead
of having to be dynamically allocated at boot time.

Cc: Thomas Weißschuh <[email protected]>
Suggested-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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tty: ldsic: fix tty_ldisc_autoload sysctl's proc_handler

Commit 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of
ldiscs") introduces the tty_ldisc_autoload sysctl with the wrong
proc_

tty: ldsic: fix tty_ldisc_autoload sysctl's proc_handler

Commit 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of
ldiscs") introduces the tty_ldisc_autoload sysctl with the wrong
proc_handler. .extra1 and .extra2 parameters are set to avoid other values
thant SYSCTL_ZERO or SYSCTL_ONE to be set but proc_dointvec do not uses
them.

This commit fixes this by using proc_dointvec_minmax instead of
proc_dointvec.

Fixes: 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of ldiscs")
Cc: stable <[email protected]>
Signed-off-by: Nicolas Bouchinet <[email protected]>
Reviewed-by: Lin Feng <[email protected]>
Reviewed-by: Jiri Slaby <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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[tree-wide] finally take no_llseek out

no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

At -rc1 we'll need do a mechanical

[tree-wide] finally take no_llseek out

no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

At -rc1 we'll need do a mechanical removal of no_llseek -

git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done

would do it.

Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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tty: sysfs: Add nbcon support for 'active'

Allow the 'active' attribute to list nbcon consoles.

Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Li

tty: sysfs: Add nbcon support for 'active'

Allow the 'active' attribute to list nbcon consoles.

Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>

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file: reclaim 24 bytes from f_owner

We do embedd struct fown_struct into struct file letting it take up 32
bytes in total. We could tweak struct fown_struct to be more compact but
really it shouldn'

file: reclaim 24 bytes from f_owner

We do embedd struct fown_struct into struct file letting it take up 32
bytes in total. We could tweak struct fown_struct to be more compact but
really it shouldn't even be embedded in struct file in the first place.

Instead, actual users of struct fown_struct should allocate the struct
on demand. This frees up 24 bytes in struct file.

That will have some potentially user-visible changes for the ownership
fcntl()s. Some of them can now fail due to allocation failures.
Practically, that probably will almost never happen as the allocations
are small and they only happen once per file.

The fown_struct is used during kill_fasync() which is used by e.g.,
pipes to generate a SIGIO signal. Sending of such signals is conditional
on userspace having set an owner for the file using one of the F_OWNER
fcntl()s. Such users will be unaffected if struct fown_struct is
allocated during the fcntl() call.

There are a few subsystems that call __f_setown() expecting
file->f_owner to be allocated:

(1) tun devices
file->f_op->fasync::tun_chr_fasync()
-> __f_setown()

There are no callers of tun_chr_fasync().

(2) tty devices

file->f_op->fasync::tty_fasync()
-> __tty_fasync()
-> __f_setown()

tty_fasync() has no additional callers but __tty_fasync() has. Note
that __tty_fasync() only calls __f_setown() if the @on argument is
true. It's called from:

file->f_op->release::tty_release()
-> tty_release()
-> __tty_fasync()
-> __f_setown()

tty_release() calls __tty_fasync() with @on false
=> __f_setown() is never called from tty_release().
=> All callers of tty_release() are safe as well.

file->f_op->release::tty_open()
-> tty_release()
-> __tty_fasync()
-> __f_setown()

__tty_hangup() calls __tty_fasync() with @on false
=> __f_setown() is never called from tty_release().
=> All callers of __tty_hangup() are safe as well.

From the callchains it's obvious that (1) and (2) end up getting called
via file->f_op->fasync(). That can happen either through the F_SETFL
fcntl() with the FASYNC flag raised or via the FIOASYNC ioctl(). If
FASYNC is requested and the file isn't already FASYNC then
file->f_op->fasync() is called with @on true which ends up causing both
(1) and (2) to call __f_setown().

(1) and (2) are the only subsystems that call __f_setown() from the
file->f_op->fasync() handler. So both (1) and (2) have been updated to
allocate a struct fown_struct prior to calling fasync_helper() to
register with the fasync infrastructure. That's safe as they both call
fasync_helper() which also does allocations if @on is true.

The other interesting case are file leases:

(3) file leases
lease_manager_ops->lm_setup::lease_setup()
-> __f_setown()

Which in turn is called from:

generic_add_lease()
-> lease_manager_ops->lm_setup::lease_setup()
-> __f_setown()

So here again we can simply make generic_add_lease() allocate struct
fown_struct prior to the lease_manager_ops->lm_setup::lease_setup()
which happens under a spinlock.

With that the two remaining subsystems that call __f_setown() are:

(4) dnotify
(5) sockets

Both have their own custom ioctls to set struct fown_struct and both
have been converted to allocate a struct fown_struct on demand from
their respective ioctls.

Interactions with O_PATH are fine as well e.g., when opening a /dev/tty
as O_PATH then no file->f_op->open() happens thus no file->f_owner is
allocated. That's fine as no file operation will be set for those and
the device has never been opened. fcntl()s called on such things will
just allocate a ->f_owner on demand. Although I have zero idea why'd you
care about f_owner on an O_PATH fd.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

tty: simplify tty_dev_name_to_number() using guard(mutex)

In tty_dev_name_to_number(), a guard can help to make the code easier to
follow. Especially how 0 is returned in the successful case. So use

tty: simplify tty_dev_name_to_number() using guard(mutex)

In tty_dev_name_to_number(), a guard can help to make the code easier to
follow. Especially how 0 is returned in the successful case. So use a
guard there.

Signed-off-by: Jiri Slaby (SUSE) <[email protected]>
Reviewed-by: Ilpo Järvinen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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usb: cdc-acm: return correct error code on unsupported break

In ACM support for sending breaks to devices is optional.
If a device says that it doenot support sending breaks,
the host must respect t

usb: cdc-acm: return correct error code on unsupported break

In ACM support for sending breaks to devices is optional.
If a device says that it doenot support sending breaks,
the host must respect that.
Given the number of optional features providing tty operations
for each combination is not practical and errors need to be
returned dynamically if unsupported features are requested.

In case a device does not support break, we want the tty layer
to treat that like it treats drivers that statically cannot
support sending a break. It ignores the inability and does nothing.
This patch uses EOPNOTSUPP to indicate that.

Signed-off-by: Oliver Neukum <[email protected]>
Fixes: 9e98966c7bb94 ("tty: rework break handling")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: add new helper function tty_get_tiocm

There is no in-kernel function to get the status register of a tty device
like the TIOCMGET ioctl returns to userspace. Create a new function,
tty_get_tioc

tty: add new helper function tty_get_tiocm

There is no in-kernel function to get the status register of a tty device
like the TIOCMGET ioctl returns to userspace. Create a new function,
tty_get_tiocm(), to obtain the status register that other portions of the
kernel can call if they need this information, and move the existing
internal tty_tiocmget() function to use this interface.

Signed-off-by: Florian Eckert <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

show more ...

tty: core: the rest to u8

There are still last minor users in the tty core that still reference
characters by the 'char' type. Switch them to u8.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kerne

tty: core: the rest to u8

There are still last minor users in the tty core that still reference
characters by the 'char' type. Switch them to u8.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: make tty_operations::send_xchar accept u8 char

tty_operations::send_xchar is one of the last users of 'char' type for
characters in the tty layer. Convert it to u8 now.

Signed-off-by: "Jiri Sl

tty: make tty_operations::send_xchar accept u8 char

tty_operations::send_xchar is one of the last users of 'char' type for
characters in the tty layer. Convert it to u8 now.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Cc: Karsten Keil <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Marcel Holtmann <[email protected]>
Cc: Johan Hedberg <[email protected]>
Cc: Luiz Augusto von Dentz <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: remove unneeded mbz from tiocsti()

'mbz' in tiocsti() is used only to pass TTY_NORMAL to
tty_ldisc_ops::receive_buf(). But that can be achieved easier by simply
passing NULL to ::receive_buf().

tty: remove unneeded mbz from tiocsti()

'mbz' in tiocsti() is used only to pass TTY_NORMAL to
tty_ldisc_ops::receive_buf(). But that can be achieved easier by simply
passing NULL to ::receive_buf().

So drop this 'mbz'.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: deprecate tty_write_message()

tty_write_message() has only one user: quotas. In particular, there the
use depends on CONFIG_PRINT_QUOTA_WARNING. And that is deprecated and
marked as BROKEN alre

tty: deprecate tty_write_message()

tty_write_message() has only one user: quotas. In particular, there the
use depends on CONFIG_PRINT_QUOTA_WARNING. And that is deprecated and
marked as BROKEN already too.

So make tty_write_message() dependent on that very config option. This
action in fact drops tty_write_message() from the vmlinux binary. Good
riddance.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Cc: Jan Kara <[email protected]>
Acked-by: Jan Kara <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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tty: whitespaces in descriptions corrected by replacing tabs with spaces

Tabs were used in the function description, to make this look more
uniform, the tabs were replaced by spaces where necessary.

tty: whitespaces in descriptions corrected by replacing tabs with spaces

Tabs were used in the function description, to make this look more
uniform, the tabs were replaced by spaces where necessary.

While we're at it, I also replaced the 'ndashes' with simple dashes, since
only those are supported by sphinx.

Reviewed-by: Jiri Slaby <[email protected]>
Signed-off-by: Florian Eckert <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: convert to new timestamp accessors

Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <[email protected]>
Link: https://lore.kernel.org/r/20231004185347.8

tty: convert to new timestamp accessors

Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

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tty: Remove now superfluous sentinel element from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) wh

tty: Remove now superfluous sentinel element from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%[email protected]/)

Remove sentinel from tty_table

Signed-off-by: Joel Granados <[email protected]>
Reviewed-by: Jiri Slaby <[email protected]>
Signed-off-by: Luis Chamberlain <[email protected]>

show more ...

tty: use 'if' in send_break() instead of 'goto'

Now, the "jumped-over" code is simple enough to be put inside an 'if'.
Do so to make it 'goto'-less.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@ke

tty: use 'if' in send_break() instead of 'goto'

Now, the "jumped-over" code is simple enough to be put inside an 'if'.
Do so to make it 'goto'-less.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: don't check for signal_pending() in send_break()

msleep_interruptible() will check on its own. So no need to do the check
in send_break() before calling the above.

Signed-off-by: "Jiri Slaby (

tty: don't check for signal_pending() in send_break()

msleep_interruptible() will check on its own. So no need to do the check
in send_break() before calling the above.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: early return from send_break() on TTY_DRIVER_HARDWARE_BREAK

If the driver sets TTY_DRIVER_HARDWARE_BREAK, we leave ops->break_ctl()
to the driver and return from send_break(). But we do it usin

tty: early return from send_break() on TTY_DRIVER_HARDWARE_BREAK

If the driver sets TTY_DRIVER_HARDWARE_BREAK, we leave ops->break_ctl()
to the driver and return from send_break(). But we do it using a local
variable and keep the code flowing through the end of the function.
Instead, do 'return' immediately with the ops->break_ctl()'s return
value.

This way, we don't have to stuff the 'else' branch of the 'if' with the
software break handling. And we can re-indent the function too.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: stop using ndash in kernel-doc

An ndash used instead of a single dash renders a bullet to the result.
So use only single dashes in kernel-doc.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@ker

tty: stop using ndash in kernel-doc

An ndash used instead of a single dash renders a bullet to the result.
So use only single dashes in kernel-doc.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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kill do_each_thread()

Eric has pointed out that we still have 3 users of do_each_thread().
Change them to use for_each_process_thread() and kill this helper.

There is a subtle change, after do_each

kill do_each_thread()

Eric has pointed out that we still have 3 users of do_each_thread().
Change them to use for_each_process_thread() and kill this helper.

There is a subtle change, after do_each_thread/while_each_thread g == t ==
&init_task, while after for_each_process_thread() they both point to
nowhere, but this doesn't matter.

> Why is for_each_process_thread() better than do_each_thread()?

Say, for_each_process_thread() is rcu safe, do_each_thread() is not.

And certainly

for_each_process_thread(p, t) {
do_something(p, t);
}

looks better than

do_each_thread(p, t) {
do_something(p, t);
} while_each_thread(p, t);

And again, there are only 3 users of this awkward helper left. It should
have been killed years ago and in fact I thought it had already been
killed. It uses while_each_thread() which needs some changes.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Cc: "Christian Brauner (Microsoft)" <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: Jiri Slaby <[email protected]> # tty/serial
Signed-off-by: Andrew Morton <[email protected]>

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tty: use min() for size computation in iterate_tty_read()

The computation is more obvious with min().

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/20230

tty: use min() for size computation in iterate_tty_read()

The computation is more obvious with min().

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

tty: switch size and count types in iterate_tty_read() to size_t

ld->ops->read() returns ssize_t. copy_to_iter() returns size_t. So
switch the variables ('size' and 'copied', respectively) to the
co

tty: switch size and count types in iterate_tty_read() to size_t

ld->ops->read() returns ssize_t. copy_to_iter() returns size_t. So
switch the variables ('size' and 'copied', respectively) to the
corresponding types.

This allows for use of min() in the next patch.

Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...