STRUCT SEC_REQUEST(9)

✨ NAME ✨

Okay so struct sec_request(9) is from the Kernel API Manual, and it's literally struct sec_request - data associate with a single crypto request. That's the whole vibe bestie, no cap. 💅

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🎀 SYNOPSIS 🎀

Here's the struct in all its glory — every field, fr fr:

struct sec_request {
    struct list_head elements;
    int num_elements;
    struct mutex lock;
    struct sec_alg_tfm_ctx *tfm_ctx;
    int len_in;
    int len_out;
    dma_addr_t dma_iv;
    int err;
    struct crypto_async_request *req_base;
    void (*cb)(struct sec_bd_info *resp, struct crypto_async_request
*req);
    struct list_head backlog_head;
 };

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💅 MEMBERS 💅

• elements — List of subparts of this request (hardware size restriction). It's giving "we had to chop it up."
• num_elements — The number of subparts (used as an optimization). Lowkey handy.
• lock — Protect elements of this structure against concurrent change. Do not skip this one, bestie.
• tfm_ctx — hardware specific context. Iconic little context holder.
• len_in — length of in sgl from upper layers. Length check, periodt.
• len_out — length of out sgl from upper layers. Outgoing sgl tea.
• dma_iv — initialization vector - phsyical address. Yes, that spelling is exactly what the page says — keep it moving.
• err — store used to track errors across subelements of this request. Error tracking main character energy.
• req_base — pointer to base element of associate crypto context. This is needed to allow shared handling skcipher, ahash etc. Shared handling slay.
• cb — completion callback. Callback cutie.
• backlog_head — list head to allow backlog maintenance. Backlog maintenance vibes.

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🦋 DESCRIPTION 🦋

The hardware is limited in the maximum size of data that it can process from a single BD. Typically this is fairly large (32MB) but still requires the complexity of splitting the incoming skreq up into a number of elements complete with appropriate iv chaining.

TL;DR bestie: big-ish limit, but the split-into-elements + iv chaining drama is very real. 🌸

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🔥 SEE ALSO 🔥

Kernel file ./drivers/crypto/hisilicon/sec/sec_drv.h — go read it, and also check out these icons:

• struct sec_queue_ring_cmd(9)
• struct sec_alg_tfm_ctx(9)
• struct sec_request_el(9)
• struct sec_queue(9)
• struct sec_hw_sge(9)
• struct sec_hw_sgl(9)
• struct sec_dev_info(9)

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mwah 💋 — this page is from ./drivers/crypto/hisilicon/sec, dated October 2026. 🫶 Obsessed with this kernel crypto lore, ngl.