cxgb4_best_mtu(9)

💅 cxgb4_best_mtu(9) — a Kernel API Manual moment

okay bestie, welcome to section 9 of the kernel API manual, where we hang out with cxgb4_best_mtu 🦋 this one is short and sweet and honestly kind of iconic for it.

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✨ NAME ✨

cxgb4_best_mtu — find the entry in the MTU table closest to an MTU 🎀

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✨ SYNOPSIS ✨

unsigned int cxgb4_best_mtu (const unsigned short *mtus , unsigned short
mtu , unsigned int *idx );

like, yes, it's one function, and yes, it returns an unsigned int, no cap ✨

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✨ ARGUMENTS ✨

• mtus — the HW MTU table 👑 this is the table we're shopping in.
• mtu — the target MTU 💖 the vibe we're trying to match.
• idx — index of selected entry in the MTU table 🎯 the address where the chosen index gets stashed.

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✨ DESCRIPTION ✨

okay so here's the tea ☕ this function returns the index and the value in the HW MTU table that is closest to but does not exceed mtu. so like, at most mtu, never over 😌

and there's one little exception bestie — unless mtu is smaller than any value in the table, in which case that smallest available value is selected. so if you're asking for something tinier than the tiniest thing on offer, you get the tiniest thing on offer. it's giving "we did our best, this is the floor" 🫶

no over-shooting, no under-delivering (except when you literally can't). that's the whole rule, fr fr 💅

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✨ SEE ALSO ✨

• Kernel file ./drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
• cxgb4_change_mac(9)
• cxgb4_write_rss(9)
• setup_rss(9)
• setup_sge_queues(9)
• cxgb4_set_rspq_intr_params(9)
• cxgb4_create_server(9)
• cxgb4_best_aligned_mtu(9)
• cxgb4_port_chan(9)
• cxgb4_port_e2cchan(9)
• cxgb4_port_viid(9)
• cxgb4_port_idx(9)
• cxgb_up(9)

like, go read the whole friend group, they're all slaying in their own way 🌈

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and that's the page!! 🌸 this little cutie came from ./drivers/net/ethernet/chelsio... and it's dated October 2026 — so yeah, mark your calendars, periodt 💜🎀