On Wed, Mar 04 2009, Geert Uytterhoeven wrote:
> Hi,
>
> Below is the rewrite of the PS3 Video RAM Storage Driver as a plain block
> device, as requested by Arnd Bergmann.
>
> The MTD-based PS3 Video RAM Storage Driver was integrated into the mainline
> kernel in 2.6.29-rc1.
>
> Ideally, we think it would be best if the existing MTD-based ps3vram driver
> would be replaced by the new block-based ps3vram driver before 2.6.29 is
> released. This would relieve the burden of supporting two different swap space
> schemes on PS3 (swap on /dev/mtdblock0 vs. /dev/ps3vram) from the distro
> maintainer's shoulders, as in that case there would never have been a stable
> kernel version containing the MTD-based ps3vram driver.
>
> What do you think? If this is accepted, I'll submit a patch to remove the MTD
> ps3vram and add the new driver as ps3vram (instead of ps3vram-ng).
>
> Thanks for your (review and other) comments!
I'd rewrite this as a ->make_request_fn handler instead. Then you can
get rid of the kernel thread. IOW, change
queue = blk_init_queue(ps3vram_request, &priv->lock);
to
queue = blk_alloc_queue(GFP_KERNEL);
blk_queue_make_request(queue, ps3vram_make_request);
Add error handling of course, and call blk_queue_max_*() to set your
limits for this device. Then add a ps3vram_make_request() ala:
static void ps3vram_do_request(struct request_queue *q, struct bio *bio)
{
struct ps3_system_bus_device *dev = q->queuedata;
struct ps3vram_priv *priv = dev->core.driver_data;
int write, res, err = -EIO;
struct bio_vec *bv;
sector_t sector;
loff_t offset;
size_t len, retlen;
int i;
write = bio_data_dir(bio) == WRITE;
sector = bio->bi_sector;
bio_for_each_segment(bv, bio, i) {
char *ptr = page_address(bv->bv_page) + bv->bv_offset;
len = bv->bv_len;
offset = sector << 9;
if (write)
res = ps3vram_write(dev, offset, len, &retlen, ptr);
else
res = ps3vram_read(dev, offset, len, &retlen, ptr);
if (res) {
dev_err(&dev->core, "%s failed\n", op);
goto out;
}
if (retlen != len) {
dev_err(&dev->core, "Short %s\n", op);
goto out;
}
sector += (len >> 9);
}
dev_dbg(&dev->core, "%s completed\n", op);
err = 0;
out:
bio_endio(bio, err);
}
I just typed it here, so if it doesn't compile you get to keep the
pieces :-)
Since ps3 is very RAM limited, I didn't bother with any highmem mapping
for the bio, since I gather that isn't an issue on that platform. You
may want to detail that in a comment above the page_addres() thing at
the top of the loop, though.
--
Jens Axboe
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev
