STRUCT MTD_WRITE_REQ(9)

💅 struct mtd_write_req(9) 💅

okay bestie, welcome to the Kernel API Manual ✨ — this is the whole entire page about struct mtd_write_req, which is literally the data structure you use when you wanna request a write operation. it's giving "small struct, big responsibilities" fr fr 🎀

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🌸 NAME 🌸

struct mtd_write_req — the data structure for requesting a write operation 🫶 (yes that's it, that's the whole vibe)

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✨ SYNOPSIS ✨

here's the literal shape of it, copy it exactly, no improvising:

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

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💖 Members 💖

each field, one by one, no skipping 😤

• start — the start address. that's where the whole thing begins 📍
• len — length of the data buffer. careful tho: only the lower 32 bits are used — the rest is just vibes 💀
• ooblen — length of the OOB buffer. same story: only the lower 32 bits are used 🙈
• usr_data — the user-provided data buffer, aka where your actual bytes live 🍓
• usr_oob — the user-provided OOB buffer 🦋
• mode — the MTD mode (peep "MTD operation modes" for the tea) 👑
• padding — reserved!! must be set to 0 — do not touch, do not decorate, just zero it and move on 💅

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🌈 Description 🌈

so this structure is the main character for ioctl(MEMWRITE) operations 🔥 it lets you do data writes and/or OOB writes in various modes, which is honestly so versatile of it.

here's the little cheat sheet:

• wanna write OOB-only? set usr_data == NULL ✨
• wanna write data-only? set usr_oob == NULL ✨

bestie pls 😭 setting both usr_data and usr_oob to NULL is NOT allowed. like, at all. don't do it. i'm begging.

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🦋 SEE ALSO 🦋

go read these next, iykwim 💜

• Kernel file ./include/uapi/mtd/mtd-abi.h struct
• mtd_read_req_ecc_stats(9)
• struct mtd_read_req(9)
• struct mtd_ecc_stats(9)

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and that's the whole page!! 💖 mwah 🫶 this little cutie lives over in ./include/uapi/mtd, dated October 2026, and it's filed under struct mtd_write_req(9) in the Kernel API Manual — periodt 💅✨🌸