Re: [PATCH] usb-storage: Add a limitation for blk_queue_max_hw_sectors()

[Christoph Hellwig]

> +     if (max_sectors > 0) {
> +             struct device *dev = us->pusb_dev->bus->sysdev;
> +             size_t max_dma_sectors = dma_max_mapping_size(dev) >>
> +                                      SECTOR_SHIFT;
> +
> +             max_sectors = min_t(size_t, max_sectors, max_dma_sectors);
> +             blk_queue_max_hw_sectors(sdev->request_queue, max_sectors);

I think we need to do this unconditionally for the rare (or maybe even
theoretical case) of a dma max mapping size smaller than the default
max_sectos.

So something like this:

        blk_queue_max_hw_sectors(sdev->request_queue,
                min_t(unsigned long,
                        queue_max_hw_sectors(sdev->request_queue),
                        dma_max_mapping_size(dev) >> SECTOR_SHIFT));