es58x_check_msg_max_len(9)

💅 es58x_check_msg_max_len(9) — like, the vibe-check for your message size

okay so bestie, welcome to the Kernel API Manual ✨ this one's a lil macro from the kernel, and honestly? she's serving "bouncer at the club door" energy 🫶

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🌸 NAME 🌸

es58x_check_msg_max_len — check the maximum size of a received message. that's it, that's the job 💖

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🎀 SYNOPSIS 🎀

es58x_check_msg_max_len (dev , msg , actual_len );

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✨ ARGUMENTS ✨

• dev — the device 🖥️ it's literally just here so we can print error messages, that's her whole purpose, no cap.
• msg — the received message 📨 and listen: it must not be a pointer. like, at all. not even a little. periodt.
• actual_len — the length of the message as advertised in the command header 📏 (as in, what the message claims her size is — we're checking receipts here).

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🦋 DESCRIPTION 🦋

okay so the reason this has to be a macro 😭 is that it needs to accept all the different types of messages as an input, and a regular function simply could not. it's giving flexible, it's giving versatile.

use this one with messages of variable sizes 🎀 she only does ONE thing: check that the message is not bigger than the maximum expected size. that's the whole gig. no notes. 👑

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💜 RETURN 💜

• zero on success 🎉 — everything's chill, message is within bounds.
• -EOVERFLOW if actual_len is greater than the expected length 💀 — yeah, that message is doing too much, she's too big, we're overflowing.

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🌈 SEE ALSO 🌈

kernel file ./drivers/net/can/usb/etas_es58x/es58x_core.h, plus the whole friend group 💖:

• enum es58x_driver_info(9)
• enum es58x_physical_layer(9)
• enum es58x_sync_edge(9)
• enum es58x_flag(9)
• enum es58x_err(9)
• enum es58x_event(9)
• struct es58x_priv(9)
• struct es58x_parameters(9)
• struct es58x_operators(9)
• struct es58x_sw_version(9)
• struct es58x_hw_revision(9)
• struct es58x_device(9)
• es58x_sizeof_es58x_device(9)
• es58x_check_msg_len(9)
• es58x_msg_num_element(9)
• es58x_priv(9)
• ES58X_SIZEOF_URB_CMD(9)
• es58x_get_urb_cmd_len(9)
• es58x_get_netdev(9)
• es58x_get_raw_can_id(9)
• es58x_get_flags(9)

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bestie reminder 🫶: this macro is a maximum check only — it doesn't check the minimum, it doesn't check everything, it checks that one specific thing. don't go expecting more from her, she's doing her best 💅

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alright that's the whole page, mwah 💋 this one lives in ./drivers/net/can/usb/etas_es58x and the docs are dated October 2026 — iconic, timeless, we stan a future-dated manpage 🧚⭐