mirror of
https://github.com/Fishwaldo/linux-bl808.git
synced 2025-06-17 20:25:19 +00:00
b580b93664
Add an O_NOTIFICATION_PIPE flag that can be passed to pipe2() to indicate that the pipe being created is going to be used for notifications. This suppresses the use of splice(), vmsplice(), tee() and sendfile() on the pipe as calling iov_iter_revert() on a pipe when a kernel notification message has been inserted into the middle of a multi-buffer splice will be messy. The flag is given the same value as O_EXCL as it seems unlikely that this flag will ever be applicable to pipes and I don't want to use up another O_* bit unnecessarily. An alternative could be to add a pipe3() system call. Signed-off-by: David Howells <dhowells@redhat.com>
58 lines
1.9 KiB
C
58 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
|
#ifndef _UAPI_LINUX_WATCH_QUEUE_H
|
|
#define _UAPI_LINUX_WATCH_QUEUE_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/fcntl.h>
|
|
|
|
#define O_NOTIFICATION_PIPE O_EXCL /* Parameter to pipe2() selecting notification pipe */
|
|
|
|
enum watch_notification_type {
|
|
WATCH_TYPE_META = 0, /* Special record */
|
|
WATCH_TYPE__NR = 1
|
|
};
|
|
|
|
enum watch_meta_notification_subtype {
|
|
WATCH_META_REMOVAL_NOTIFICATION = 0, /* Watched object was removed */
|
|
WATCH_META_LOSS_NOTIFICATION = 1, /* Data loss occurred */
|
|
};
|
|
|
|
/*
|
|
* Notification record header. This is aligned to 64-bits so that subclasses
|
|
* can contain __u64 fields.
|
|
*/
|
|
struct watch_notification {
|
|
__u32 type:24; /* enum watch_notification_type */
|
|
__u32 subtype:8; /* Type-specific subtype (filterable) */
|
|
__u32 info;
|
|
#define WATCH_INFO_LENGTH 0x0000007f /* Length of record */
|
|
#define WATCH_INFO_LENGTH__SHIFT 0
|
|
#define WATCH_INFO_ID 0x0000ff00 /* ID of watchpoint */
|
|
#define WATCH_INFO_ID__SHIFT 8
|
|
#define WATCH_INFO_TYPE_INFO 0xffff0000 /* Type-specific info */
|
|
#define WATCH_INFO_TYPE_INFO__SHIFT 16
|
|
#define WATCH_INFO_FLAG_0 0x00010000 /* Type-specific info, flag bit 0 */
|
|
#define WATCH_INFO_FLAG_1 0x00020000 /* ... */
|
|
#define WATCH_INFO_FLAG_2 0x00040000
|
|
#define WATCH_INFO_FLAG_3 0x00080000
|
|
#define WATCH_INFO_FLAG_4 0x00100000
|
|
#define WATCH_INFO_FLAG_5 0x00200000
|
|
#define WATCH_INFO_FLAG_6 0x00400000
|
|
#define WATCH_INFO_FLAG_7 0x00800000
|
|
};
|
|
|
|
|
|
/*
|
|
* Extended watch removal notification. This is used optionally if the type
|
|
* wants to indicate an identifier for the object being watched, if there is
|
|
* such. This can be distinguished by the length.
|
|
*
|
|
* type -> WATCH_TYPE_META
|
|
* subtype -> WATCH_META_REMOVAL_NOTIFICATION
|
|
*/
|
|
struct watch_notification_removal {
|
|
struct watch_notification watch;
|
|
__u64 id; /* Type-dependent identifier */
|
|
};
|
|
|
|
#endif /* _UAPI_LINUX_WATCH_QUEUE_H */
|