mlx5dv_open_device(3)

💅 mlx5dv_open_device — open an RDMA device context for the mlx5 provider

okay bestie, gather round, because this is the mlx5dv_open_device(3) page and it's literally the front door to the mlx5 provider. no cap. 💖

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✨ SYNOPSIS ✨

like, the whole vibe in two lines:

#include <infiniband/mlx5dv.h>

struct ibv_context *
mlx5dv_open_device(struct ibv_device *device, struct mlx5dv_context_attr *attr);

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🌸 DESCRIPTION 🌸

So what does it do? It opens an RDMA device context — but with specific mlx5 provider attributes attached. not just any context, an mlx5-flavored one. iconic behavior honestly. 👑

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🎀 ARGUMENTS 🎀

• device — the RDMA device you wanna open. that's the one, bestie.
• attr — the attribute struct, detailed below 👇

🦋 mlx5dv_context_attr

the struct itself, character for character, no edits:

struct mlx5dv_context_attr {
        uint32_t flags;
        uint64_t comp_mask;
        struct ibv_fd_arr *fds;
};

flags

a bitwise OR of the various values described below. (yes, OR them together, that's the whole point 💅)

• MLX5DV_CONTEXT_FLAGS_DEVX — allocate a DEVX context. that's it, that's the flag.

comp_mask

a bitmask specifying what fields in the structure are actually valid — like a little vibe check for your struct ✨

• MLX5DV_CONTEXT_ATTR_MASK_FD_ARRAY — means there's a valid value in fds.

fds

used to pass a file descriptor array. that's its whole job. 🫶

🧚 ibv_fd_arr

struct ibv_fd_arr {
        int *arr;
        uint32_t count;
};

• arr — pointer to the file descriptor array.
• count — number of elements in the array. like, how many. mhm.

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🔥 RETURN VALUE 🔥

it returns a pointer to the allocated device context. and if the request fails? NULL. that's the whole story, ngl. 😭

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🌈 SEE ALSO 🌈

• ibv_open_device(3)

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👑 AUTHOR 👑

Yishai Hadas <yishaih@mellanox.com> — thank you for your service, fr fr 🫡

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and that's the page!! this whole thing came from the mlx5dv_open_device(3) man page, footer and all — same title, same manual section, no extra lore invented, promise 🤞💜

k bye bestie, go open some device contexts 💅✨🎀