STRUCT IOMMU_USER_DATA_ARRAY(9)

💅 struct iommu_user_data_array — Kernel API Manual ✨

okay so bestie, gather round, because this one is lowkey a whole vibe. it's from the Kernel API Manual, and it's literally the struct that describes an array of iommu driver–specific user space data. yes, an array. not one, a whole squad. 🫶

---

🌸 NAME 🌸

struct iommu_user_data_array — iommu driver specific user space data array

like, it's giving "user space sent us a whole list of requests and we gotta handle them all." periodt. 👑

---

🎀 SYNOPSIS 🎀

struct iommu_user_data_array {
    unsigned int type;
    void __user *uptr;
    size_t entry_len;
    u32 entry_num;
 };

there she is. four members, zero notes, absolutely iconic. ⭐

---

🦋 Members 🦋

• type — the data type of all the entries in the user buffer array. yes, every single one of them. no mixing and matching, bestie, they all gotta match. 💅
• uptr — pointer to the user buffer array. it's the address where the whole lineup lives. 📍
• entry_len — the fixed-width length of an entry in the array, and it's measured in bytes. fixed-width means every entry is the same size, no cap. 📏
• entry_num — the number of total entries in the array. the headcount. the whole roster. 🔢

---

💜 Description 💜

so the user buffer includes an array of requests, and the format of those requests is defined in include/uapi/linux/iommufd.h. that's the blueprint, the source of truth, the whole aesthetic. go look there if you want the actual layout, because that's where it lives. 🗂️✨

---

🌈 SEE ALSO 🌈

Kernel file ./include/linux/iommu.h, plus the whole friend group:

• struct iommu_fault_page_request(9)
• struct iommu_fault(9)
• enum iommu_page_response_code(9)
• struct iommu_page_response(9)
• struct iopf_queue(9)
• struct iommu_resv_region(9)
• struct iommu_iotlb_gather(9)
• struct iommu_dirty_bitmap(9)
• struct iommu_dirty_ops(9)
• struct iommu_user_data(9)
• __iommu_copy_struct_from_user(9)
• iommu_copy_struct_from_user(9)
• __iommu_copy_struct_from_user_array(9)
• iommu_copy_struct_from_user_array(9)
• iommu_copy_struct_from_full_user_array(9)
• __iommu_copy_struct_to_user(9)
• iommu_copy_struct_to_user(9)
• struct iommu_ops(9)
• struct iommu_domain_ops(9)
• struct iommu_device(9)
• struct iommu_fault_param(9)
• struct dev_iommu(9)
• iommu_iotlb_gather_is_disjoint(9)
• iommu_iotlb_gather_add_range(9)
• iommu_iotlb_gather_add_page(9)
• struct iommu_fwspec(9)
• struct iommu_sva(9)
• iommu_map_sgtable(9)

---

and that's the whole page, bestie, no crumbs left behind 🍓💖

sign-off szn: this little beauty comes from ./include/linux and it's dated October 2026. manifesting that date being real for you. mwah. 🧚‍♀️💫