Re: [PATCH v2 3/4] btrfs: Add zstd support

[David Sterba]

On Thu, Jun 29, 2017 at 12:41:07PM -0700, Nick Terrell wrote:
> +static void zstd_free_workspace(struct list_head *ws)
> +{
> +	struct workspace *workspace = list_entry(ws, struct workspace, list);
> +
> +	vfree(workspace->mem);
> +	kfree(workspace->buf);
> +	kfree(workspace);
> +}
> +
> +static struct list_head *zstd_alloc_workspace(void)
> +{
> +	ZSTD_parameters params =
> +			zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
> +	struct workspace *workspace;
> +
> +	workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
> +	if (!workspace)
> +		return ERR_PTR(-ENOMEM);
> +
> +	workspace->size = max_t(size_t,
> +			ZSTD_CStreamWorkspaceBound(params.cParams),
> +			ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
> +	workspace->mem = vmalloc(workspace->size);
> +	workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
> +	if (!workspace->mem || !workspace->buf)
> +		goto fail;
> +
> +	INIT_LIST_HEAD(&workspace->list);
> +
> +	return &workspace->list;
> +fail:
> +	zstd_free_workspace(&workspace->list);
> +	return ERR_PTR(-ENOMEM);
> +}

In the next iteration, please update the workspace allocations so that
they use kvmalloc/kvfree and GFP_KERNEL (eg. 6acafd1eff426).