STRUCT P9_CONN(9)

🦋 struct p9_conn(9) — the fd mux connection state info page, bestie edition 🦋

okay so this is a page from the Kernel API Manual, and it's literally all about struct p9_conn — the fd mux connection state information. yes that's the whole NAME section, and yes it's short, we love a concise queen 💅

✨ SYNOPSIS ✨

like, here's the whole struct, copied exactly, no cap:

struct p9_conn {
    struct list_head mux_list;
    struct p9_client *client;
    int err;
    spinlock_t req_lock;
    struct list_head req_list;
    struct list_head unsent_req_list;
    struct p9_req_t *rreq;
    struct p9_req_t *wreq;
    char tmp_buf[P9_HDRSZ];
    struct p9_fcall rc;
    int wpos;
    int wsize;
    char *wbuf;
    struct list_head poll_pending_link;
    struct p9_poll_wait poll_wait[MAXPOLLWADDR];
    poll_table pt;
    struct work_struct rq;
    struct work_struct wq;
    unsigned long wsched;
 };

🎀 Members 🎀

okay so let's go through every single member, one by one, because we do not skip 💖

• mux_list — list link for mux to manage multiple connections (the original literally has a (?) there, and honestly? same, bestie, we're keeping the question mark, iykyk 🙈)
• client — reference to client instance for this connection
• err — error state
• req_lock — lock protecting req_list and requests statuses
• req_list — accounting for requests which have been sent
• unsent_req_list — accounting for requests that haven't been sent (the "not yet" girlies, we see you 🌸)
• rreq — read request
• wreq — write request
• tmp_buf — temporary buffer to read in header
• rc — temporary fcall for reading current frame
• wpos — write position for current frame
• wsize — amount of data to write for current frame
• wbuf — current write buffer
• poll_pending_link — pending links to be polled per conn
• poll_wait — array of wait_q's for various worker threads
• pt — poll state
• rq — current read work
• wq — current write work
• wsched — ???? and honestly the manpage itself said it with four question marks so we keep the four question marks 💀 the docs are as confused as we are, fr fr

👑 SEE ALSO 👑

the Kernel file ./net/9p/trans_fd.c and like, this whole friend group of functions — go say hi bestie 🫶:

• struct p9_trans_fd(9)
• p9_conn_cancel(9)
• p9_fd_read(9)
• p9_read_work(9)
• p9_fd_write(9)
• p9_write_work(9)
• p9_pollwait(9)
• p9_conn_create(9)
• p9_poll_mux(9)
• p9_fd_request(9)
• p9_conn_destroy(9)
• p9_fd_close(9)
• p9_poll_workfn(9)

ok and a lil sign-off note 🎀 this one came from ./net/9p and it's dated October 2026 — so like, future girlie behavior, iconic. go read the source, drink some water, and slay your kernel debugging session, periodt 💜✨