usb_alloc_urb(9)

💖 usb_alloc_urb(9) 💖

okay so bestie, welcome to the Kernel API Manual — this is the page for usb_alloc_urb, and yes it's literally the moment your USB driver gets its very own urb to play with. main character energy from the first line, no cap ✨

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🌸 NAME 🌸

usb_alloc_urb — creates a new urb for a USB driver to use 🦋

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✨ SYNOPSIS ✨

struct urb * usb_alloc_urb (int iso_packets , gfp_t mem_flags );

like, that's the whole signature, she's little but she's powerful 💅

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🎀 ARGUMENTS 🎀

• iso_packets — number of iso packets for this urb. that's it, that's the number 🍓
• mem_flags — the type of memory to allocate; go peek at kmalloc for the list of valid options for this one, iykyk 💜

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🦋 DESCRIPTION 🦋

so what she does: creates an urb for the USB driver to use, initializes a few internal structures, increments the usage counter, and returns a pointer to it. cute, efficient, iconic 👑

if the driver wants to use this urb for interrupt, control, or bulk endpoints, pass '0' as the number of iso packets. that's the move 🙈

⚠️ bestie listen — the driver must call usb_free_urb when it is finished with the urb. no leaving her hanging, fr fr 😭

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⭐ RETURN ⭐

a pointer to the new urb, or NULL if no memory is available. that's the whole vibe check 💀

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🌈 SEE ALSO 🌈

kernel file ./drivers/usb/core/urb.c — plus the whole friend group, and yes we're listing every single one because nobody gets left out 🫶

• usb_init_urb(9)
• usb_free_urb(9)
• usb_get_urb(9)
• usb_anchor_urb(9)
• usb_unanchor_urb(9)
• usb_pipe_type_check(9)
• usb_urb_ep_type_check(9)
• usb_submit_urb(9)
• usb_unlink_urb(9)
• usb_kill_urb(9)
• usb_poison_urb(9)
• usb_block_urb(9)
• usb_kill_anchored_urbs(9)
• usb_poison_anchored_urbs(9)
• usb_unpoison_anchored_urbs(9)
• usb_anchor_suspend_wakeups(9)
• usb_anchor_resume_wakeups(9)
• usb_wait_anchor_empty_timeout(9)
• usb_get_from_anchor(9)
• usb_scuttle_anchored_urbs(9)
• usb_anchor_empty(9)

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and that's the page!! mwah 💋 this one lives in ./drivers/usb/core, dated October 2026, page usb_alloc_urb(9) — go allocate something iconic, love u, bye 🧚‍♀️💖