lpfc_idiag_extacc_read(9)

📦 version 7.3.1, in nixpkgs unstable

💅 lpfc_idiag_extacc_read — ok so hear me out, bestie

This one lives in the Kernel API Manual, which is like the group chat of kernel docs where everybody's a (9) and everyone's got lore. Sit down, grab a strawberry 🍓, and let's get into it.

✨ NAME ✨

lpfc_idiag_extacc_read — the idiag debugfs read access to extent information, aka the little function that goes and fetches your extent info for you 💖

🦋 SYNOPSIS 🦋

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

Look at her. Four args, one ssize_t return. Iconic behavior, no cap. ✨

🎀 ARGUMENTS 🎀

  • file — the file pointer you're reading from. Like, that's the whole vibe, that's where the data lives 🫶
  • buf — the buffer where the data gets copied to. This is the destination, the main character, the place things end up 💅
  • nbytes — how many bytes you wanna read. Count 'em, bestie 🔢
  • ppos — the position in the file where reading starts. Not from the top, from here 👑

🌸 DESCRIPTION 🌸

So here's the tea: this routine reads data from the proper extent information — and by "proper" we mean it picks the right one according to the idiag command, iykyk — and then copies it all to the user buf. That's it. That's the function. It's giving "small but crucial." Literally just a fetch-and-hand-off and honestly? We respect it. 💜

🔥 RETURN 🔥

This function returns the amount of data that was read — and yes, girlie, that could be less than nbytes if the end of the file was reached 😭 (happens to the best of us) — or a negative error value if things went sideways 💀

Fr fr, check the return. If it's negative, that's not a vibe, that's an error.

👑 SEE ALSO 👑

The kernel file where all the magic is written:

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

And now the whole extended friend group, in order, every single one of them (we do not skip anyone in this house 🫶):

okay that's the whole page, bestie, you ate that 💅✨

Little sign-off moment 🎀: this one's filed under ./drivers/scsi/lpfc, dated October 2026. Go read the source, slay, and remember — negative return values are not the vibe. Bye bye! 🦋🌸

📦 where this page comes from