> +/*
> + * This must only be called once all bios have been issued so that the refcount
> + * can only decrease. This just waits for all bios to complete.
> + * Returns the length of bytes copied or error
> + */
> +static ssize_t blkdev_copy_wait_io_completion(struct blkdev_copy_io *cio)
Hi, Nitesh,
don't functions waiting for completion usually set their names to 'wait_for_completion_'?
(e.g. blkdev_copy_wait_for_completion_io)
> +ssize_t blkdev_copy_offload(struct block_device *bdev, loff_t pos_in,
> + loff_t pos_out, size_t len,
> + void (*endio)(void *, int, ssize_t),
> + void *private, gfp_t gfp)
> +{
> + struct blkdev_copy_io *cio;
> + struct blkdev_copy_offload_io *offload_io;
> + struct bio *src_bio, *dst_bio;
> + ssize_t rem, chunk, ret;
> + ssize_t max_copy_bytes = bdev_max_copy_sectors(bdev) << SECTOR_SHIFT;
wouldn't it be better to use size_t for variables that don't return?
values such as chunk and max_copy_bytes may be defined as 'unsigned'.
> + struct blk_plug plug;
> +
> + if (!max_copy_bytes)
> + return -EOPNOTSUPP;
> +
> + ret = blkdev_copy_sanity_check(bdev, pos_in, bdev, pos_out, len);
> + if (ret)
> + return ret;
> +
> + cio = kzalloc(sizeof(*cio), GFP_KERNEL);
> + if (!cio)
> + return -ENOMEM;
> + atomic_set(&cio->refcount, 1);
> + cio->waiter = current;
> + cio->endio = endio;
> + cio->private = private;
> +
> + /*
> + * If there is a error, copied will be set to least successfully
> + * completed copied length
> + */
> + cio->copied = len;
> + for (rem = len; rem > 0; rem -= chunk) {
> + chunk = min(rem, max_copy_bytes);
> +
> + offload_io = kzalloc(sizeof(*offload_io), GFP_KERNEL);
> + if (!offload_io)
> + goto err_free_cio;
> + offload_io->cio = cio;
> + /*
> + * For partial completion, we use offload_io->offset to truncate
> + * successful copy length
> + */
> + offload_io->offset = len - rem;
> +
> + src_bio = bio_alloc(bdev, 0, REQ_OP_COPY_SRC, gfp);
> + if (!src_bio)
> + goto err_free_offload_io;
> + src_bio->bi_iter.bi_size = chunk;
> + src_bio->bi_iter.bi_sector = pos_in >> SECTOR_SHIFT;
> +
> + blk_start_plug(&plug);
> + dst_bio = blk_next_bio(src_bio, bdev, 0, REQ_OP_COPY_DST, gfp);
> + if (!dst_bio)
> + goto err_free_src_bio;
> + dst_bio->bi_iter.bi_size = chunk;
> + dst_bio->bi_iter.bi_sector = pos_out >> SECTOR_SHIFT;
> + dst_bio->bi_end_io = blkdev_copy_offload_dst_endio;
> + dst_bio->bi_private = offload_io;
> +
> + atomic_inc(&cio->refcount);
> + submit_bio(dst_bio);
> + blk_finish_plug(&plug);
> + pos_in += chunk;
> + pos_out += chunk;
> + }
> +
> + if (atomic_dec_and_test(&cio->refcount))
> + blkdev_copy_endio(cio);
> + if (cio->endio)
Isn't it a problem if the memory of cio is released in blkdev_copy_endio()?
It is unlikely to occur if there is an inflight i/o earlier,
it would be nice to modify considering code flow.
> + return -EIOCBQUEUED;
> +
> + return blkdev_copy_wait_io_completion(cio);
> +
> +err_free_src_bio:
> + bio_put(src_bio);
> +err_free_offload_io:
> + kfree(offload_io);
> +err_free_cio:
> + cio->copied = min_t(ssize_t, cio->copied, (len - rem));
> + cio->status = -ENOMEM;
> + if (rem == len) {
> + kfree(cio);
> + return cio->status;
isn't it a problem if the memory of cio is released?
Best Regards,
Jinyoung.
