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| author | Jiri Slaby <jslaby@suse.cz> | 2021-07-23 12:31:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-27 12:12:07 +0200 |
| commit | 8d29e0024437ae9184ae24f817ef0fda80b8cd3c (patch) | |
| tree | 991d6b6e6df8956bdde4d83c5025b89fc95e4352 /include/linux/tty_buffer.h | |
| parent | 56eef46aa830824d5046a765d695a78bc0c34fed (diff) | |
| download | lwn-8d29e0024437ae9184ae24f817ef0fda80b8cd3c.tar.gz lwn-8d29e0024437ae9184ae24f817ef0fda80b8cd3c.zip | |
tty: move tty_buffer definitions to new tty_buffer.h
tty.h is large enough currently. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_buffer.h and move there tty_buffer-related
declarations and function prototypes.
Note that many of the tty_buffer.c function prototypes reside now in
tty_flip.h. But we cannot move struct tty_buffer & friends because:
* tty_insert_flip_char() in tty_flip.h needs both struct tty_port and
struct tty_buffer defined.
* struct tty_port in tty_port.h needs struct tty_buffer defined.
So if we moved struct tty_buffer to tty_flip.h too, tty_flip.h would
need tty_port.h and that would need tty_flip.h (to have tty_buffer)
again. Hence we introduce new header tty_buffer.h here to break this
circular dependency.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/tty_buffer.h')
| -rw-r--r-- | include/linux/tty_buffer.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/tty_buffer.h b/include/linux/tty_buffer.h new file mode 100644 index 000000000000..3b9d77604291 --- /dev/null +++ b/include/linux/tty_buffer.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_TTY_BUFFER_H +#define _LINUX_TTY_BUFFER_H + +#include <linux/atomic.h> +#include <linux/llist.h> +#include <linux/mutex.h> +#include <linux/workqueue.h> + +struct tty_buffer { + union { + struct tty_buffer *next; + struct llist_node free; + }; + int used; + int size; + int commit; + int read; + int flags; + /* Data points here */ + unsigned long data[]; +}; + +/* Values for .flags field of tty_buffer */ +#define TTYB_NORMAL 1 /* buffer has no flags buffer */ + +static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs) +{ + return ((unsigned char *)b->data) + ofs; +} + +static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs) +{ + return (char *)char_buf_ptr(b, ofs) + b->size; +} + +struct tty_bufhead { + struct tty_buffer *head; /* Queue head */ + struct work_struct work; + struct mutex lock; + atomic_t priority; + struct tty_buffer sentinel; + struct llist_head free; /* Free queue head */ + atomic_t mem_used; /* In-use buffers excluding free list */ + int mem_limit; + struct tty_buffer *tail; /* Active buffer */ +}; + +/* + * When a break, frame error, or parity error happens, these codes are + * stuffed into the flags buffer. + */ +#define TTY_NORMAL 0 +#define TTY_BREAK 1 +#define TTY_FRAME 2 +#define TTY_PARITY 3 +#define TTY_OVERRUN 4 + +#endif |