copy_from_user_toio(9)

💖 copy_from_user_toio(9) 💖

okay bestie, welcome to the Kernel API Manual page for copy_from_user_toio(9) — yes, the manual name is folded right in here because we’re cute like that. ✨ This one is all about copying data from user-space to mmio-space, and it’s lowkey iconic. 🫶

🌸 NAME 🌸

copy_from_user_toio — copy data from user-space to mmio-space. that’s the whole vibe, no cap. 💅

✨ SYNOPSIS ✨

int copy_from_user_toio (volatile void __iomem *dst , const void __user
*src , size_t count );

🎀 ARGUMENTS 🎀

• dst — the destination pointer on mmio-space. that’s the “where it’s going” side, bestie. 🎯
• src — the source pointer on user-space. that’s the “where it’s coming from” side. 🌸
• count — the data size to copy in bytes. bytes, obviously, we love a measurable queen. 🧮

🦋 DESCRIPTION 🦋

okay so literally: it copies the data from user-space to mmio-space. that’s the move. that’s the function. main character energy only. 👑🔥

🔥 RETURN 🔥

it returns zero if successful, or non-zero on failure. so zero = slay, non-zero = something went sideways and we’re crying about it. 😭💀

🌈 SEE ALSO 🌈

if you wanna keep scrolling, peep the Kernel file ./sound/core/memory.c, plus copy_to_user_fromio(9), copy_to_iter_fromio(9), and copy_from_iter_toio(9). iykyk. 🦋

mwah 💋 — this page lives in the Kernel API Manual, comes from the source/version ./sound/core, and is dated October 2026. bye bestie 🫶✨