[Deepin-Kernel-SIG] [linux 6.18.y] [FROMLIST] media: mtk-jpeg: only init/cancel work for multi-core variants

[Avenger-285714]

Single-core variants of this hardware do not use the work at all, and the worker function is set to NULL, which leads to warnings when cancelling the work in release callback.

Skip the work init/cancel code when the JPEG hardware isn't multi-core.

Cc: stable@vger.kernel.org
Fixes: 34c519feef3e ("media: mtk-jpeg: fix use-after-free in release path due to uncancelled work")
Fixes: d40e952 ("media: mtk-jpeg: reconstructs the initialization mode of worker")

Link: https://lore.kernel.org/all/20260601073218.1281840-1-zhengxingda@iscas.ac.cn/

Summary by Sourcery

Bug Fixes:

• Avoid warnings and potential misuse by skipping work initialization and cancellation on single-core Mediatek JPEG hardware that does not use the worker.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Guard workqueue initialization and cancellation in the MediaTek JPEG driver so that work items are only set up and torn down for multi-core hardware variants, avoiding warnings and potential issues on single-core variants where the worker callback is NULL.

Sequence diagram for guarded workqueue init/cancel in mtk_jpeg_open/mtk_jpeg_release

sequenceDiagram
    actor User
    participant File
    participant mtk_jpeg_core
    participant Workqueue

    User->>File: open
    File->>mtk_jpeg_core: mtk_jpeg_open
    mtk_jpeg_core->>mtk_jpeg_core: check jpeg_variant_multi_core
    alt [jpeg->variant->multi_core]
        mtk_jpeg_core->>Workqueue: INIT_WORK(ctx_jpeg_work, jpeg_worker)
    else [single core]
        mtk_jpeg_core-->>Workqueue: (no INIT_WORK)
    end

    User->>File: release
    File->>mtk_jpeg_core: mtk_jpeg_release
    mtk_jpeg_core->>mtk_jpeg_core: check jpeg_variant_multi_core
    alt [jpeg->variant->multi_core]
        mtk_jpeg_core->>Workqueue: cancel_work_sync(ctx_jpeg_work)
    else [single core]
        mtk_jpeg_core-->>Workqueue: (no cancel_work_sync)
    end

Loading

File-Level Changes

Change	Details	Files
Guard work initialization and cancellation with the multi_core variant flag to avoid operating on unused work for single-core JPEG hardware.	Wrap INIT_WORK for ctx->jpeg_work in a check for jpeg->variant->multi_core within mtk_jpeg_open() so work is only initialized on multi-core variants Wrap cancel_work_sync(&ctx->jpeg_work) in a check for jpeg->variant->multi_core within mtk_jpeg_release() so work is only cancelled when it was initialized	drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c

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[Copilot]

Pull request overview

Backport of an upstream fix for the Mediatek JPEG driver: single-core variants do not assign a jpeg_worker and never use ctx->jpeg_work, so calling INIT_WORK with a NULL function and cancel_work_sync on an uninitialized work item triggers warnings. The fix gates both calls on variant->multi_core.

Changes:

• Guard INIT_WORK(&ctx->jpeg_work, ...) in mtk_jpeg_open with jpeg->variant->multi_core.
• Guard cancel_work_sync(&ctx->jpeg_work) in mtk_jpeg_release with the same check.

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[sourcery-ai]

Hey - I've left some high level feedback:

• Since jpeg->variant->multi_core now gates both INIT_WORK() and cancel_work_sync(), consider adding a small comment near the condition explaining that single-core variants never queue jpeg_work, to make the rationale clear for future maintainers adding new variants.
• If feasible within this driver’s patterns, you might add a sanity check (e.g. WARN_ON(!jpeg->variant->jpeg_worker) when multi_core is true) to catch misconfigured variants that declare multi-core support but do not provide a worker callback.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Since `jpeg->variant->multi_core` now gates both `INIT_WORK()` and `cancel_work_sync()`, consider adding a small comment near the condition explaining that single-core variants never queue `jpeg_work`, to make the rationale clear for future maintainers adding new variants.
- If feasible within this driver’s patterns, you might add a sanity check (e.g. `WARN_ON(!jpeg->variant->jpeg_worker)` when `multi_core` is true) to catch misconfigured variants that declare multi-core support but do not provide a worker callback.

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