drm_client_b...r_vmap_local(9)

💅 drm_client_buffer_vmap_local(9) — a Kernel API Manual moment

ok so real talk, bestie, this is from the Kernel API Manual and the page is literally called drm_client_b...r_vmap_local(9) (yes the truncation is canon, we don't ask questions 💀). Let me walk you through it, iykyk.

---

✨ NAME ✨

drm_client_buffer_vmap_local — maps a DRM client buffer into address space. That's the whole vibe. 🎀

🌸 SYNOPSIS 🌸

int drm_client_buffer_vmap_local (struct drm_client_buffer *buffer ,
                                  struct iosys_map *map_copy );

like, that's the signature, copy it exactly, do not @ me.

🦋 ARGUMENTS 🦋

• buffer — the DRM client buffer. the main character fr.
• map_copy — returns the mapped memory's address. it's giving "output parameter" energy, we love a function that fills things in for you 🫶

💖 DESCRIPTION 💖

okay so. This function maps a client buffer into kernel address space. super chill. and — plot twist — if the buffer is already mapped, it just returns the existing mapping's address. no drama, no double work, iconic. ✨

here's the part where you need to listen tho, bestie: client buffer mappings are not ref'counted. literally not refcounted. so every single call to drm_client_buffer_vmap_local should be closely followed by a call to drm_client_buffer_vunmap_local. they're a package deal, a duo, a two-piece set 💅. (if you want long-term mappings instead, go look at drm_client_buffer_vmap — different function, different commitment level.)

and now the fun bit: the returned address is a copy of the internal value. in contrast to other vmap interfaces, you don't need it for the client's vunmap function. so you can modify it at will during blit and draw operations. go off, customize it, it's yours 🎨🔥

👑 RETURN 👑

0 on success, or a negative errno code otherwise. that's it, that's the whole return section. short and sweet, like a good text back 💌

🌈 SEE ALSO 🌈

• Kernel file ./drivers/gpu/drm/drm_client.c overview(9)
• drm_client_init(9)
• drm_client_register(9)
• drm_client_release(9)
• drm_client_buffer_delete(9)
• drm_client_buffer_vunmap_local(9)
• drm_client_buffer_vmap(9)
• drm_client_buffer_vunmap(9)
• drm_client_buffer_create_dumb(9)
• drm_client_buffer_flush(9)

like a little friend group of functions, all linked up, all slaying in their own lane 🌸

---

ngl bestie, the "not ref'counted" bit is the actual danger zone here. map it, then unmap it, close. no leaving it hanging, no vibes-based cleanup, fr fr 😭

---

and that's the whole page! source is ./drivers/gpu/drm, dated October 2026, and the man page goes by drm_client_b...r_vmap_local(9). mwah 💋 stay mapping, stay unmapping, periodt. 🧚💜