qeth_send_control_data(9)

hiii bestie 💖 welcome to qeth_send_control_data(9) from the Kernel API Manual — this is the page where we send control command to the card, and honestly it’s giving main-character kernel energy ✨

🌸 NAME 🌸

qeth_send_control_data — send control command to the card 💌

✨ SYNOPSIS ✨

int qeth_send_control_data (struct qeth_card *card , struct
       qeth_cmd_buffer *iob , int (*reply_cb)(struct qeth_card *cb_card, struct
       qeth_reply *cb_reply, unsigned long cb_cmd) , void *reply_param );

🎀 ARGUMENTS 🎀

• card — qeth_card structure pointer 🫶
• iob — qeth_cmd_buffer pointer 📨
• reply_cb — callback function pointer, and it comes with lore:
  • cb_card: pointer to the qeth_card structure
  • cb_reply: pointer to the qeth_reply structure
  • cb_cmd: pointer to the original iob for non-IPA commands, or to the qeth_ipa_cmd structure for the IPA commands.
• reply_param — private pointer passed to the callback 🔒

🦋 DESCRIPTION 🦋

okay so bestie, the callback function gets called one or more times, with cb_cmd pointing to the response returned by the hardware. no cap, that’s the whole vibe.

The callback function must return:

• > 0 if more reply blocks are expected
• 0 if the last or only reply block is received
• < 0 on error

⚠️ this return-value contract is literally not optional — > 0 = more reply blocks expected, 0 = last or only reply block received, < 0 = error 😭

The callback function can get the value of the reply_param pointer from the field 'param' of the structure qeth_reply. iykyk 💅

🌈 SEE ALSO 🌈

• Kernel file ./drivers/s390/net/qeth_core_main.c
• qeth_irq(9)
• qeth_prep_flush_pack_buffer(9)
• qeth_get_elements_for_frags(9)
• qeth_count_elements(9)
• qeth_add_hw_header(9)
• qeth_fill_buffer(9)
• qeth_vm_request_mac(9)
• qeth_enable_hw_features(9)

xoxo, your kernel bestie 💅 this page came from ./drivers/s390/net, dated October 2026, and it’s literally qeth_send_control_data(9) — periodt 🫶