iommu_group_set_iommudata(9)

💅 iommu_group_set_iommudata — like, the kernel API manual page for it, bestie

okay so real talk: this is from the Kernel API Manual, the whole page is iommu_group_set_iommudata(9), and it's about stashing your own lil data blob on an iommu group. tiny page, immaculate vibes, let's go 🎀

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✨ NAME ✨

iommu_group_set_iommudata — set iommu_data for a group 🫶

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🌸 SYNOPSIS 🌸

void iommu_group_set_iommudata (struct iommu_group *group , void
*iommu_data , void (*release)(void *iommu_data) );

like yes it's one line of C and yes it's lowkey gorgeous 💜

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🦋 ARGUMENTS 🦋

• group — the group. the actual star of the show, the main character, the group.
• iommu_data — new data. the fresh stuff you're putting in there ✨
• release — release function for iommu_data. so like, the cleanup handler for your data, the one that gets called to let it go 😭

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👑 DESCRIPTION 👑

so here's the tea: iommu drivers can store data in the group for use when doing iommu operations. iconic behavior, honestly.

this function provides a way to set the data after the group has been allocated — which is the whole point, right, because sometimes you can't do it up front, and that's fine, we're not judging 💅

⚠️ important bestie caveat: the caller should hold a group reference. that's not optional energy, that's the rules. don't be out here setting data on a group you don't have a reference to, fr fr 🙈

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/iommu/iommu.c

and the whole friend group, in order, no skips, no cap:

• iommu_device_register(9)
• iommu_insert_resv_region(9)
• iommu_group_alloc(9)
• iommu_group_get_iommudata(9)
• iommu_group_set_name(9)
• iommu_group_add_device(9)
• iommu_group_remove_device(9)
• iommu_group_mutex_assert(9)
• iommu_group_for_each_dev(9)
• iommu_group_get(9)
• iommu_group_ref_get(9)
• iommu_group_put(9)
• iommu_group_id(9)
• device_iommu_capable(9)
• iommu_group_has_isolated_msi(9)
• iommu_set_fault_handler(9)
• iommu_paging_domain_alloc_flags(9)
• iommu_attach_device(9)
• iommu_get_domain_for_dev(9)
• iommu_driver_get_domain_for_dev(9)
• iommu_attach_group(9)
• iommu_unmap(9)
• iommu_unmap_fast(9)
• report_iommu_fault(9)
• iommu_get_resv_regions(9)
• iommu_put_resv_regions(9)
• iommu_setup_default_domain(9)
• iommu_device_use_default_domain(9)
• iommu_device_unuse_default_domain(9)
• iommu_group_claim_dma_owner(9)
• iommu_device_claim_dma_owner(9)
• iommu_group_release_dma_owner(9)
• iommu_device_release_dma_owner(9)
• iommu_group_dma_owner_claimed(9)
• iommu_replace_device_pasid(9)
• iommu_attach_handle_get(9)
• iommu_attach_group_handle(9)
• iommu_detach_group_handle(9)
• iommu_replace_group_handle(9)
• pci_dev_reset_iommu_prepare(9)
• pci_dev_reset_iommu_done(9)
• iommu_dma_prepare_msi(9)

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and that's the whole page, bestie — go forth and set that iommu_data, but hold that reference first, iykyk 💖

mwah 💋 this lil number lives in ./drivers/iommu, dated October 2026 — catch you in the next release, slay 🌟