EFADV_QUERY_CQ(3)

🦋 EFADV_QUERY_CQ — the EFA Direct Verbs manual, bestie edition ✨

okay so this is efadv_query_cq(3), from the EFA Direct Verbs Manual. it's the one that lets you peek at all the device-specific deets on a Completion Queue. lowkey iconic. 💅

---

✨ NAME ✨

efadv_query_cq — query EFA specific Completion Queue attributes 🎀

---

🌸 SYNOPSIS 🌸

#include <infiniband/efadv.h>

int efadv_query_cq(struct ibv_cq *ibvcq, struct efadv_cq_attr *attr,
                   uint32_t inlen);

---

💜 DESCRIPTION 💜

efadv_query_cq() queries device-specific Completion Queue attributes. that's it, that's the whole vibe. 🫶

compatibility is handled using the comp_mask and inlen fields — the way that this struct just knows how to stay compatible? obsessed.

struct efadv_cq_attr {
    uint64_t comp_mask;
    uint8_t *buffer;
    uint32_t entry_size;
    uint32_t num_entries;
    uint32_t *doorbell;
};

• inlen — In: the size of struct efadv_cq_attr. tell it how big the struct is, it's only polite bestie 💖
• comp_mask — the compatibility mask. keeping everything chill across versions ✨
• buffer — the completion queue buffer. the actual goods 🎁
• entry_size — size of each completion queue entry. every entry living its own main character life 💫
• num_entries — maximal number of entries in the completion queue. the max capacity, no cap 🔥
• doorbell — the reverse doorbell used to update the device of polled entries and to request notifications. it's NULL when not in use for this Completion Queue. no doorbell, no problem 🙈

---

🌈 RETURN VALUE 🌈

efadv_query_cq() returns 0 on success, or the value of errno on failure (which indicates the failure reason). so if you get a 0, slay. anything else, check errno — it's literally telling you what went wrong 💀

---

🦋 SEE ALSO 🦋

• efadv(7) — go read the big one, iykyk 👑

---

🎀 NOTES 🎀

• Compatibility mask (comp_mask) is an out field and currently has no values. so bestie, it's giving empty — for now ⭐

---

👑 AUTHORS 👑

Michael Margolin mrgolin@amazon.com — the icon who made this happen, periodt 💅

---

okay that's the whole page, and yes it's efa (that's the manual name, folded in right up top like a lil name tag 🏷️), dated 2025-04-15, shipping with version 2025-04-15 of the EFA Direct Verbs Manual. mwah, go forth and query your CQs responsibly bestie 💖✨🧚