unassign_co...domain_store(9)

👑 unassign_co...domain_store(9) — the Kernel API Manual page, bestie edition 👑

Okay so real talk, this page lives in the Kernel API Manual and it's all about unassign_control_domain_store, and honestly? She's a vibe. Let me break her down for you.

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✨ NAME ✨

unassign_control_domain_store — the function that parses the domain ID from @buf and then clears the corresponding bit in the mediated matrix device's ADM. That's it, that's the whole job. Clean. Simple. Iconic. 💅

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🌸 SYNOPSIS 🌸

ssize_t unassign_control_domain_store (struct device *dev , struct
device_attribute *attr , const char *buf , size_t count );

Four params, no drama. Type is ssize_t btw, in case you were wondering. 💖

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🦋 ARGUMENTS 🦋

• dev — the matrix device. She's the main character here, everything happens around her.
• attr — the mediated matrix device's unassign_control_domain attribute. Yes, that one. That specific one. 🎀
• buf — a buffer containing the domain ID that's about to get unassigned. Bye bestie 👋
• count — the number of bytes in buf. Gotta know how much, fr fr.

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💀 RETURN 💀

So here's the tea: you get back the number of bytes processed if the domain ID is valid. Slay. ✨

But if it's not valid? She returns one of these errors, and you better be ready:

• -EINVAL — if the ID is not a number. bestie that's literally not a number, what were you even doing 😭
• -ENODEV — if the ID exceeds the maximum value configured for the system. Too big. Over it. Over the limit. 🚩

Not me stressing over validation errors — but seriously, handle your return values, okay? 🫶

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🌈 SEE ALSO 🌈

First off, the Kernel file lives right here:

./drivers/s390/crypto/vfio_ap_ops.c

And now, the group chat — the whole squad, every single one, no cap:

• get_update_locks_for_kvm(9)
• release_update_locks_for_kvm(9)
• get_update_locks_for_mdev(9)
• release_update_locks_for_mdev(9)
• get_update_locks_by_apqn(9)
• get_update_locks_for_queue(9)
• vfio_ap_mdev_get_queue(9)
• vfio_ap_wait_for_irqclear(9)
• vfio_ap_free_aqic_resources(9)
• vfio_ap_irq_disable(9)
• vfio_ap_validate_nib(9)
• ensure_nib_shared(9)
• vfio_ap_irq_enable(9)
• vfio_ap_le_guid_to_be_uuid(9)
• handle_pqap(9)
• vfio_ap_mdev_verify_no_sharing(9)
• vfio_ap_mdev_validate_masks(9)
• assign_adapter_store(9)
• vfio_ap_mdev_unlink_adapter(9)
• unassign_adapter_store(9)
• assign_domain_store(9)
• unassign_domain_store(9)
• assign_control_domain_store(9)
• vfio_ap_mdev_set_kvm(9)
• vfio_ap_mdev_unset_kvm(9)
• vfio_ap_mdev_resource_in_use(9)
• vfio_ap_mdev_hot_unplug_cfg(9)
• vfio_ap_mdev_cfg_remove(9)
• vfio_ap_mdev_on_cfg_remove(9)
• vfio_ap_filter_apid_by_qtype(9)
• vfio_ap_mdev_cfg_add(9)
• vfio_ap_mdev_on_cfg_add(9)
• vfio_ap_on_cfg_changed(9)

Like, all thirty-three of them. I counted. You're welcome. 🧚

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And that's the whole page! 🎀 This one comes to you straight from ./drivers/s390/crypto, dated October 2026, and it's titled unassign_co...domain_store(9) — abbreviated with the ... and everything, she's mysterious like that. Bye bestie, go unassign some control domains responsibly 💜⭐