blk_stat_alloc_callback(9)

💅 blk_stat_alloc_callback(9) — a whole little page from the Kernel API Manual, bestie

okay so picture this: you're deep in the kernel, you want block statistics, and you need a callback to hold all your stats buckets. that's this function. her whole job is allocating the block statistics callback. no cap. 🎀

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✨ SYNOPSIS ✨

struct blk_stat_callback * blk_stat_alloc_callback (void
(*timer_fn)(struct blk_stat_callback *) , int (*bucket_fn)(const struct
request *) , unsigned int buckets , void *data );

like, look at her. four arguments, one glorious pointer back. 🔥

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🫶 ARGUMENTS 🫶

• timer_fn — the timer callback function. yes, the same struct's timer callback. she's the one who gets called on the timer vibes.
• bucket_fn — the bucket callback function. she decides the bucket situation.
• buckets — number of statistics buckets. it's unsigned int, so pls don't come at her with a negative number, that's not the vibe. 🌸
• data — the value that gets dropped into the data field of the struct blk_stat_callback. a little gift. a little payload. iconic. 💖

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🌈 DESCRIPTION 🌈

not gonna lie, the description is short and she is thriving in her minimalism era:

See struct blk_stat_callback for details on the callback functions.

that's it. that's the description. literally go read the struct if you want the tea on how the callback functions actually work. iykyk. ⭐

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👑 RETURN 👑

you get a struct blk_stat_callback on success 💅 — or NULL on ENOMEM, which is giving "the memory said no ma'am." 😭 so like, always check, bestie. always check.

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🦋 SEE ALSO 🦋

• Kernel file ./block/blk-stat.h — yes the actual file, go look at it 🧚
• struct blk_stat_callback(9)
• blk_stat_add_callback(9)
• blk_stat_remove_callback(9)
• blk_stat_free_callback(9)
• blk_stat_is_active(9)
• blk_stat_activate_nsecs(9)
• blk_stat_activate_msecs(9)

like the whole blk-stat friend group showed up to the function. we love a supportive squad. 🍓

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mwah 💜 that's the page!! sourced from ./block (that's the section, queen), and it's dated October 2026, and the whole thing is filed under blk_stat_alloc_callback(9). go forth and allocate responsibly, bestie. 🌸✨