rxe_get_mcg(9)

💅 rxe_get_mcg(9) — the Kernel API Manual, but make it make sense

okay so bestie, we're in the Kernel API Manual today and this page is literally called rxe_get_mcg. yes the name is a mouthful, no we are not skipping it. 💖

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✨ NAME ✨

rxe_get_mcg — lookup or allocate a mcg

like, you either find the one that already exists or you make a new one. it's giving "if it's not there, build it" energy. 🎀

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🦋 SYNOPSIS 🦋

struct rxe_mcg * rxe_get_mcg (struct rxe_dev *rxe , union ib_gid *mgid
);

that's the whole incantation, copy it exactly, no cap. 🔥

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🌸 ARGUMENTS 🌸

• rxe — the rxe device object. your main character struct, the one doing the work 💅
• mgid — the multicast IP address, but served to you as a gid. same vibe, different outfit ✨

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👑 RETURN 👑

you get the mcg on success. that's the win, that's the slay 🫶

and if it doesn't work out? you get ERR_PTR(error). not a null, not a shrug, an actual error pointer. check it, bestie, i'm begging 😭

fr fr: ERR_PTR(error) is not a valid mcg. test it before you dereference it or the kernel will simply end you 💀

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🌈 SEE ALSO 🌈

all the siblings and cousins live in the kernel file ./drivers/infiniband/sw/rxe/rxe_mcast.c, and here's the whole group chat:

• rxe_mcast_add(9)
• rxe_mcast_del(9)
• __rxe_insert_mcg(9)
• __rxe_remove_mcg(9)
• __rxe_lookup_mcg(9)
• rxe_lookup_mcg(9)
• __rxe_init_mcg(9)
• __rxe_publish_mcg(9)
• rxe_cleanup_mcg(9)
• __rxe_destroy_mcg(9)
• rxe_destroy_mcg(9)
• __rxe_init_mca(9)
• rxe_attach_mcg(9)
• __rxe_cleanup_mca(9)
• rxe_detach_mcg(9)
• rxe_attach_mcast(9)
• rxe_detach_mcast(9)

that's seventeen functions, i counted, and every single one of them is staying on this list. obsessed with the completeness 🧚💜

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ngl the double-underscore ones are the ✨private✨ ones — you didn't hear it from me 🙈

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and that's the page!! sign-off time: this whole thing lives in ./drivers/infiniband/sw/rxe, and it's dated October 2026. mwah, go look up your mcg responsibly 💋🎀🦋⭐