STRUCT WATCHDOG_OPS(9)

💅 struct watchdog_ops(9) — the Kernel API Manual, bestie edition 🎀

okay so this is the struct watchdog_ops(9) page from the Kernel API Manual, and it's literally the cheat sheet for how a watchdog device does its little tasks. it's all about the lowkey function pointers that actually make the watchdog go. let's get into it ✨

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🌸 NAME 🌸

struct watchdog_ops — the watchdog-device's operations, aka the whole to-do list for a watchdog driver 🐕

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🦋 SYNOPSIS 🦋

struct watchdog_ops {
    struct module *owner;
    int (*start)(struct watchdog_device *);
    int (*stop)(struct watchdog_device *);
    int (*ping)(struct watchdog_device *);
    unsigned int (*status)(struct watchdog_device *);
    int (*set_timeout)(struct watchdog_device *, unsigned int);
    int (*set_pretimeout)(struct watchdog_device *, unsigned int);
    unsigned int (*get_timeleft)(struct watchdog_device *);
    int (*restart)(struct watchdog_device *, unsigned long, void *);
    long (*ioctl)(struct watchdog_device *, unsigned int, unsigned
long);
 };

bestie this is the whole struct, copied exact, no cap 💖

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👑 Members 👑

• owner — the module owner. like, who's the main character holding this down 🫶
• start — the routine for starting the watchdog device. it wakes the baby up ✨
• stop — the routine for stopping the watchdog device. nap time 😴
• ping — the routine that sends a keepalive ping to the watchdog device. it's giving "hey bestie I'm still here" 💌
• status — the routine that shows the status of the watchdog device. vibe check, but for the hardware 🔍
• set_timeout — the routine for setting the watchdog devices timeout value (in seconds). ⏰
• set_pretimeout — the routine for setting the watchdog devices pretimeout. the little heads-up before the chaos 🌸
• get_timeleft — the routine that gets the time left before a reset (in seconds). countdown energy 💀
• restart — the routine for restarting the machine. the big red button, iconic 🔥
• ioctl — the routines that handles extra ioctl calls. the bonus side quests 🧚

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💜 Description 💜

so <pink>the watchdog_ops structure</pink> contains a list of low-level operations that control a watchdog device. it also contains the module that owns these operations.

and here's the part that matters, so listen up 👇

the start function is mandatory. all the other functions are optional. periodt.

like — start is the main character and everybody else is a supporting cast member. no start, no show 🎬

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🌈 SEE ALSO 🌈

• Kernel file ./include/linux/watchdog.h
• struct watchdog_device(9)

go read those next, iykyk 🦋

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and that's the page!! source is ./include/linux, dated October 2026, screaming struct watchdog_ops(9) at the top and bottom of the original. mwah, slay, go ping your watchdogs 💅💖