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tty: reformat tty_struct::flags into kernel-doc

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Move the partial tty_struct::flags documentation from tty_ldisc to the
tty.h header and combine it with the one-liners present there. Convert
all those to kernel-doc. This way, we can simply reference the
documentation in Documentation while the text is still along the
definitions.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-10-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2021-11-26 09:15:57 +01:00 committed by Greg Kroah-Hartman
parent 40f4268cdd
commit 4072254f96
2 changed files with 62 additions and 36 deletions
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24
Documentation/driver-api/serial/tty.rst
View File

@ -47,28 +47,8 @@ These are documented as a part of struct tty_operations.
Flags
^^^^^
Line discipline methods have access to tty->flags field containing the
following interesting flags:
======================= =======================================================
TTY_THROTTLED Driver input is throttled. The ldisc should call
tty->driver->unthrottle() in order to resume
reception when it is ready to process more data.
TTY_DO_WRITE_WAKEUP If set, causes the driver to call the ldisc's
write_wakeup() method in order to resume
transmission when it can accept more data
to transmit.
TTY_IO_ERROR If set, causes all subsequent userspace read/write
calls on the tty to fail, returning -EIO.
TTY_OTHER_CLOSED Device is a pty and the other side has closed.
TTY_NO_WRITE_SPLIT Prevent driver from splitting up writes into
smaller chunks.
======================= =======================================================
Line discipline methods have access to :c:member:`tty_struct.flags` field. See
:doc:`tty_struct`.
Locking
^^^^^^^

74
include/linux/tty.h
View File

@ -263,26 +263,72 @@ struct tty_file_private {
/* tty magic number */
#define TTY_MAGIC 0x5401
/*
* These bits are used in the flags field of the tty structure.
/**
* DOC: TTY Struct Flags
*
* These bits are used in the :c:member:`tty_struct.flags` field.
*
* So that interrupts won't be able to mess up the queues,
* copy_to_cooked must be atomic with respect to itself, as must
* tty->write. Thus, you must use the inline functions set_bit() and
* clear_bit() to make things atomic.
*
* TTY_THROTTLED
* Driver input is throttled. The ldisc should call
* :c:member:`tty_driver.unthrottle()` in order to resume reception when
* it is ready to process more data (at threshold min).
*
* TTY_IO_ERROR
* If set, causes all subsequent userspace read/write calls on the tty to
* fail, returning -%EIO. (May be no ldisc too.)
*
* TTY_OTHER_CLOSED
* Device is a pty and the other side has closed.
*
* TTY_EXCLUSIVE
* Exclusive open mode (a single opener).
*
* TTY_DO_WRITE_WAKEUP
* If set, causes the driver to call the
* :c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume
* transmission when it can accept more data to transmit.
*
* TTY_LDISC_OPEN
* Indicates that a line discipline is open. For debugging purposes only.
*
* TTY_PTY_LOCK
* A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic.
*
* TTY_NO_WRITE_SPLIT
* Prevent driver from splitting up writes into smaller chunks (preserve
* write boundaries to driver).
*
* TTY_HUPPED
* The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`.
*
* TTY_HUPPING
* The TTY is in the process of hanging up to abort potential readers.
*
* TTY_LDISC_CHANGING
* Line discipline for this TTY is being changed. I/O should not block
* when this is set. Use tty_io_nonblock() to check.
*
* TTY_LDISC_HALTED
* Line discipline for this TTY was stopped. No work should be queued to
* this ldisc.
*/
#define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */
#define TTY_IO_ERROR 1 /* Cause an I/O error (may be no ldisc too) */
#define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */
#define TTY_EXCLUSIVE 3 /* Exclusive open mode */
#define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
#define TTY_LDISC_OPEN 11 /* Line discipline is open */
#define TTY_PTY_LOCK 16 /* pty private */
#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
#define TTY_HUPPED 18 /* Post driver->hangup() */
#define TTY_HUPPING 19 /* Hangup in progress */
#define TTY_LDISC_CHANGING 20 /* Change pending - non-block IO */
#define TTY_LDISC_HALTED 22 /* Line discipline is halted */
#define TTY_THROTTLED 0
#define TTY_IO_ERROR 1
#define TTY_OTHER_CLOSED 2
#define TTY_EXCLUSIVE 3
#define TTY_DO_WRITE_WAKEUP 5
#define TTY_LDISC_OPEN 11
#define TTY_PTY_LOCK 16
#define TTY_NO_WRITE_SPLIT 17
#define TTY_HUPPED 18
#define TTY_HUPPING 19
#define TTY_LDISC_CHANGING 20
#define TTY_LDISC_HALTED 22
static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
{