[PATCHv2 1/4] block: bio-integrity: directly map user buffers

[Pankaj Raghav]

> +static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
> +				   int nr_vecs, unsigned int len,
> +				   unsigned int direction, u32 seed)
> +{
> +	struct bio_integrity_payload *bip;
> +	struct bio_vec *copy_vec = NULL;
> +	struct iov_iter iter;
> +	void *buf;
> +	int ret;
> +
> +	/* if bvec is on the stack, we need to allocate a copy for the completion */
> +	if (nr_vecs <= UIO_FASTIOV) {
> +		copy_vec = kcalloc(sizeof(*bvec), nr_vecs, GFP_KERNEL);
> +		if (!copy_vec)
> +			return -ENOMEM;
> +		memcpy(copy_vec, bvec, nr_vecs * sizeof(*bvec));
> +	}
> +
> +	buf = kmalloc(len, GFP_KERNEL);
> +	if (!buf)
> +		goto free_copy;

ret is not set to -ENOMEM here.

> +
> +	if (direction == ITER_SOURCE) {
> +		iov_iter_bvec(&iter, direction, bvec, nr_vecs, len);
> +		if (!copy_from_iter_full(buf, len, &iter)) {
> +			ret = -EFAULT;
> +			goto free_buf;
> +		}
> +	} else {
> +		memset(buf, 0, len);
> +	}
> +
> +	/*
> +	 * We just need one vec for this bip, but we need to preserve the
> +	 * number of vecs in the user bvec for the completion handling, so use
> +	 * nr_vecs.
> +	 */
> +	bip = bio_integrity_alloc(bio, GFP_KERNEL, nr_vecs);
> +	if (IS_ERR(bip)) {
> +		ret = PTR_ERR(bip);
> +		goto free_buf;
> +	}
> +
> +	ret = bio_integrity_add_page(bio, virt_to_page(buf), len,
> +				     offset_in_page(buf));
> +	if (ret != len) {
> +		ret = -ENOMEM;
> +		goto free_bip;
> +	}
> +
> +	bip->bip_flags |= BIP_INTEGRITY_USER;
> +	bip->copy_vec = copy_vec ?: bvec;
> +	return 0;
> +free_bip:
> +	bio_integrity_free(bio);
> +free_buf:
> +	kfree(buf);
> +free_copy:
> +	kfree(copy_vec);
> +	return ret;
> +}
> +