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

Christoph Hellwig (hch@infradead.org)
Tue, 21 May 2002 13:51:08 +0100


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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