STRUCT MTD_READ_REQ(9)

✨ struct mtd_read_req(9) ✨

okay so bestie, we're in the Kernel API Manual today and this page is literally all about struct mtd_read_req — the data structure for requesting a read operation 💖 it's giving "let me read some flash memory please" and honestly? iconic.

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🌸 NAME 🌸

struct mtd_read_req — the data structure for requesting a read operation 🎀 yes that's it, that's the whole name section, she's concise and we respect it.

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🦋 SYNOPSIS 🦋

struct mtd_read_req {
    __u64 start;
    __u64 len;
    __u64 ooblen;
    __u64 usr_data;
    __u64 usr_oob;
    __u8 mode;
    __u8 padding[7];
    struct mtd_read_req_ecc_stats ecc_stats;
 };

look at her 🥹 every field accounted for, padding[7] doing its little reserved thing, we love a well-organized struct periodt.

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💅 Members 💅

• start — the start address 🫶 where the reading begins, bestie.
• len — length of the data buffer — and heads up, only the lower 32 bits are used 👀 don't go flexing those upper bits, they're not invited.
• ooblen — length of the OOB buffer — same deal, only the lower 32 bits are used 💀 the upper bits are just vibing there, unused.
• usr_data — the user-provided data buffer, literally your data's home address 🏠
• usr_oob — the user-provided OOB buffer, separate little home for the OOB data ✨
• mode — the MTD mode (see "MTD operation modes") — this is where you tell it how you wanna read, iykyk 🌈
• padding — reserved, must be set to 0 ⚠️ no cap, set it to zero, don't be weird about it.
• ecc_stats — ECC statistics for the read operation 📊 she's keeping receipts on the error correction, love that for her.

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🔥 Description 🔥

so this structure supports ioctl(MEMREAD) operations, and it's highkey versatile — it lets you do data reads and/or OOB reads in various modes 🎀 choose your own adventure fr fr.

wanna read from OOB-only? easy, set usr_data == NULL 🦋

wanna read data-only? set usr_oob == NULL ⭐

but!! and this is the important part bestie — setting both usr_data and usr_oob to NULL is not allowed 🚫🙈 that combo is a no, the struct will not be having it. don't do it.

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👑 SEE ALSO 👑

• Kernel file ./include/uapi/mtd/mtd-abi.h
• struct mtd_write_req(9) — the write-side sibling, go say hi 💜
• struct mtd_read_req_ecc_stats(9) — the ECC stats struct herself
• struct mtd_ecc_stats(9) — and the OG ECC stats struct, we stan 🌸

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and that's the whole page bestie, you ate that 🫶 mwah 💋 this little gem lives in ./include/uapi/mtd and the version tag says October 2026 — so like, future vibes, very main character energy ⏰👑 go forth and read your flash memory responsibly, mwah!! 💖✨🎀