usb_hcd_check_unlink_urb(9)

✨ NAME ✨

okay so this page is usb_hcd_check_unlink_urb(9) from the Kernel API Manual, and it's literally the vibe check for whether an URB may be unlinked. 🫶

🦋 SYNOPSIS 🦋

This is the whole signature, character for character, bestie:

int usb_hcd_check_unlink_urb (struct usb_hcd *hcd , struct urb *urb ,
int status );

🎀 ARGUMENTS 🎀

• hcd — host controller to which urb was submitted. 💖
• urb — URB being checked for unlinkability. 🦋
• status — error code to store in urb if the unlink succeeds. 🎀

💅 DESCRIPTION 💅

Host controller drivers should call this routine in their dequeue method. No cap.

⚠️ The HCD's private spinlock must be held and interrupts must be disabled. 🔥

The actions carried out here are required to make sure an unlink is valid. ✨

Here's the tea on the error codes:

• -EIDRM — urb was not submitted or has already completed. The completion function may not have been called yet. 😭
• -EBUSY — urb has already been unlinked. 💀

🔥 RETURN 🔥

0 for no error, otherwise a negative error code (in which case the dequeue method must fail). The possible error codes are: -EIDRM and -EBUSY, the two from above. 👑

🌈 SEE ALSO 🌈

Go peek at these, iykyk:

• Kernel file — ./drivers/usb/core/hcd.c
• ascii2desc(9)
• rh_string(9)
• usb_bus_init(9)
• usb_register_bus(9)
• usb_deregister_bus(9)
• register_root_hub(9)
• usb_calc_bus_time(9)
• usb_hcd_link_urb_to_ep(9)
• usb_hcd_unlink_urb_from_ep(9)
• usb_hcd_giveback_urb(9)
• usb_hcd_alloc_bandwidth(9)
• usb_hcd_reset_endpoint(9)
• usb_alloc_streams(9)
• usb_free_streams(9)
• usb_hcd_resume_root_hub(9)
• usb_bus_start_enum(9)
• usb_hcd_irq(9)
• usb_hc_died(9)
• usb_create_shared_hcd(9)
• usb_create_hcd(9)
• usb_stop_hcd(9)
• usb_add_hcd(9)
• usb_remove_hcd(9)

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xoxo 💜 sourced from ./drivers/usb/core, dated October 2026, and it's your girl usb_hcd_check_unlink_urb(9) signing off. 💅✨