ib_respond_udata(9)

💅 ib_respond_udata(9) — Kernel API Manual 🎀

okay so bestie, we're diving into ib_respond_udata from the Kernel API Manual and honestly? it's giving "small function, big responsibility." let's get into it ✨

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🌸 NAME 🌸

ib_respond_udata — copies a driver data response back to userspace, no cap 💖

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✨ SYNOPSIS ✨

ib_respond_udata (_udata , _rep );

that's the whole vibe, she's compact 🫶

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💜 ARGUMENTS 💜

• _udata — the system call's ib_udata struct. like, the userspace-facing paperwork for this call, y'know? 🎀
• _rep — a kernel buffer holding the response driver data, and she's chillin' on the stack. stack energy only 💅

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🔥 DESCRIPTION 🔥

so what she actually does: she copies the driver data response structures back to userspace in a way that's forwards and backwards compatible. both directions, she ate 💀✨

the rules of the game:

• longer kernel structs get truncated — and ngl, if userspace actually needed that truncated info, then userspace has made some kind of error. that's on them bestie 🙈
• shorter structs get zero padded — filled out so everything lines up, iconic behavior 🌈

truncate the extras, pad the gaps, ship it. periodt 👑

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🦋 SEE ALSO 🦋

kernel file ./include/rdma/uverbs_ioctl.h — go read it iykyk 📖

• uverbs_attr_get_uobjs_arr(9)
• ib_copy_validate_udata_in(9)
• ib_copy_validate_udata_in_cm(9)
• ib_is_udata_in_empty(9)
• ib_respond_empty_udata(9)
• ib_no_udata_io(9)

all the little udata besties, a whole friend group honestly 🫶💖

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mwah 💋 this page lives in ./include/rdma, dated October 2026, and she's signed ib_respond_udata(9). stan a consistent function name. slay 🌟