seq_buf_to_user(9)

💖 seq_buf_to_user(9) 💖

okay so bestie, welcome to the seq_buf_to_user(9) page from the Kernel API Manual — this is the lil function that copies your sequence buffer out to user space, and it's lowkey iconic ✨

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✨ NAME ✨

seq_buf_to_user — copy the sequence buffer to user space 🫶

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🌸 SYNOPSIS 🌸

int seq_buf_to_user (struct seq_buf *s , char __user *ubuf , size_t
start , int cnt );

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🎀 ARGUMENTS 🎀

• s — the seq_buf descriptor, your main character struct 👑
• ubuf — the userspace memory location we're copying to, that's the destination bestie 💅
• start — the first byte in the buffer to copy, like where we start the cut ✂️
• cnt — the amount to copy, the how-much of it all

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🦋 DESCRIPTION 🦋

So what it does: it copies the sequence buffer into the userspace memory pointed at by ubuf. It starts from start and writes up to cnt characters — or stops once it hits the end of the content in the buffer (s->len), whichever comes first. literally first-come-first-served energy 🌈

On failure it returns -EBUSY if all of the content in the sequence has already been read, which includes the case where there's nothing in the sequence at all (s->len == start). like, nothing left to give, the vibe check said empty 💀

It returns -EFAULT if the copy to userspace fails. rude, but okay 😭

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⭐ RETURN ⭐

On success, it returns a positive number — the number of bytes it copied 💖 slay.

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🧚 SEE ALSO 🧚

Kernel file ./lib/seq_buf.c, plus the whole friend group:

• seq_buf_can_fit(9)
• seq_buf_print_seq(9)
• seq_buf_vprintf(9)
• seq_buf_printf(9)
• seq_buf_do_printk(9)
• seq_buf_bprintf(9)
• seq_buf_puts(9)
• seq_buf_putc(9)
• seq_buf_putmem(9)
• seq_buf_putmem_hex(9)
• seq_buf_path(9)
• seq_buf_hex_dump(9)

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and that's the whole page, bestie! 🌸 sign-off time: this one lives in ./lib, dated October 2026 — no cap, go read the source if you wanna vibe with it fr fr 💜🎀