lpfc_idiag_ctlacc_read(9)

📦 version 7.3.1, in nixpkgs unstable

💅 lpfc_idiag_ctlacc_read — idiag debugfs read port and device control register

okay so bestie, welcome to the Kernel API Manual ✨ this one's about a function with a name that's honestly a mouthful: lpfc_idiag_ctlacc_read. say it with me. you got this. 🫶

🌸 SYNOPSIS 🌸

ssize_t lpfc_idiag_ctlacc_read (struct file *file , char __user *buf ,
       size_t nbytes , loff_t *ppos );

like, that's the whole signature. she's a ssize_t girlie and she returns a size. iconic. 👑

🎀 ARGUMENTS 🎀

  • file — the file pointer you're reading from. yes, that file. the one you opened. 💅
  • buf — the buffer where the data gets copied to. it's giving "destination" energy. ✨
  • nbytes — how many bytes you wanna read. the byte budget, if you will. 💖
  • ppos — the position in the file where the reading starts. your little bookmark. 🔖

🦋 DESCRIPTION 🦋

so what does she actually do? this routine reads data from the phba port and device registers — following whatever the idiag command says — and then copies it all out to the user buf. that's it. that's the vibe. register reading, then a little copy-to-userspace moment. 🧚

⭐ RETURN ⭐

this function returns the amount of data that was read 💫 — and ngl, that could be less than nbytes if the end of the file was reached, so don't come for her if it's short. or, alternatively, she hands you back a negative error value. 😭 basically: positive-ish number = data, negative = bad news.

👑 SEE ALSO 👑

the kernel file itself, no cap:

  • ./drivers/scsi/lpfc/lpfc_debugfs.c

and the whole friend group, fr fr:

like. that's a lot of siblings. she's got main character energy in a very big family. 🌈

and that's the page, bestie!! 🌸✨ this little love letter comes from ./drivers/scsi/lpfc and it's dated October 2026 — so mark your calendar and stan responsibly. 💜🎀🦋

📦 where this page comes from