EFADV_QUERY_AH(3)

💅 EFADV_QUERY_AH(3) — like, the EFA Direct Verbs manual, bestie 🦋

okay so welcome to the EFA Direct Verbs Manual, section 3, page EFADV_QUERY_AH — yes the whole title, we're doing this properly ✨

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🌸 NAME 🌸

efadv_query_ah — it queries the EFA-specific Address Handle attributes. that's it, that's the whole vibe 🎀

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✨ SYNOPSIS ✨

#include <infiniband/efadv.h>

int efadv_query_ah(struct ibv_ah *ibvah, struct efadv_ah_attr *attr,
           uint32_t inlen);

like, three args, one include, zero drama 🫶

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💖 DESCRIPTION 💖

efadv_query_ah() goes and asks the device for its device-specific Address Handle attributes. lowkey iconic of it, honestly 👑

so how do we not break everything when the struct changes? compatibility is handled using the comp_mask and inlen fields — that's the whole trick, no cap 💅

struct efadv_ah_attr {
    uint64_t comp_mask;
    uint16_t ahn;
    uint8_t reserved[6];
};

ngl this struct is serving exactly what it needs to serve:

• inlen — In: the size of struct efadv_ah_attr. just tell it how big your struct is, bestie 🍓
• comp_mask — the compatibility mask. it's the ✨vibe check✨ for which fields you're using.
• ahn — the device's Address Handle number. literally the number. that's the field. 🎀

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🔥 RETURN VALUE 🔥

efadv_query_ah() returns 0 on success — slay 💖 — or the value of errno on failure (which indicates the failure reason, so read it, don't just ignore it 😭).

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🌈 SEE ALSO 🌈

• efadv(7)

go read that one too, iykyk 🦋

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⭐ NOTES ⭐

• the compatibility mask (comp_mask) is an out field and currently has no values. so like, it's out here being out 🫶

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👑 AUTHORS 👑

Gal Pressman <galpress@amazon.com> — wrote it, we stan 💜

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fr fr do not mess with the struct layout, the inlen field is load-bearing 💀

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and that's the page!! brought to you by efa, dated 2019-05-19, filed under EFADV_QUERY_AH(3) — mwah, bestie, go query some address handles 💅✨🎀