Re: [RFC] possible fix for broken floppy driver since 2.5.13

From: Christoph Hellwig (hch@infradead.org)
Date: Tue May 21 2002 - 07:51:08 EST


On Tue, May 21, 2002 at 02:35:24PM +0200, Mikael Pettersson wrote:
> I haven't got a clue on how to program Linux' block I/O interfaces.
> Show me how to do a modern equivalent of getblk(dev,0,1024) + waiting
> for the operation to complete and I'll update the patch ASAP.

I think something like the following should do it.
(WARNING: entirely untested)

static void io_done(struct bio *bio)
{
        complete((struct completion *)bio->bi_private);
}

static int doio(struct block_device *bdev, size_t size)
{
        struct completion comp;
        struct page * page;
        struct bio * bio;

        bio = bio_alloc(GFP_KERNEL, 1);
        if (!bio)
                return -ENOMEM;

        page = alloc_page(GFP_KERNEL);
        if (!page) {
                bio_put(bio);
                return -ENOMEM;
        }

        bio->bi_sector = 0;
        bio->bi_bdev = bdev;
        bio->bi_io_vec[0].bv_page = page;
        bio->bi_io_vec[0].bv_len = size;
        bio->bi_io_vec[0].bv_offset = 0;

        bio->bi_vcnt = 1;
        bio->bi_idx = 0;
        bio->bi_size = LOGPSIZE;

        bio->bi_end_io = io_done;
        bio->bi_private = &complete;

        submit_bio(READ, bio);
        run_task_queue(&tq_disk);

        wait_for_completion(&comp);

        bio_put(bio);
        __free_page(page);

        return 0;
}

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