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Message-Id: <20211126081611.11001-10-jslaby@suse.cz>
Date: Fri, 26 Nov 2021 09:15:57 +0100
From: Jiri Slaby <jslaby@...e.cz>
To: gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 09/23] tty: reformat tty_struct::flags into kernel-doc
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@...e.cz>
---
Documentation/driver-api/serial/tty.rst | 24 +-------
include/linux/tty.h | 74 ++++++++++++++++++++-----
2 files changed, 62 insertions(+), 36 deletions(-)
diff --git a/Documentation/driver-api/serial/tty.rst b/Documentation/driver-api/serial/tty.rst
index 333a5923f6e1..65f971e3aada 100644
--- a/Documentation/driver-api/serial/tty.rst
+++ b/Documentation/driver-api/serial/tty.rst
@@ -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
^^^^^^^
diff --git a/include/linux/tty.h b/include/linux/tty.h
index da49ad9be281..7b0a5d478ef6 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -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)
{
--
2.34.0
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