// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/scatterlist.h>
#include <crypto/acompress.h>
#include "compress.h"

static int __z_erofs_crypto_decompress(struct z_erofs_decompress_req *rq,
				       struct crypto_acomp *tfm)
{
	struct sg_table st_src, st_dst;
	struct acomp_req *req;
	struct crypto_wait wait;
	const char *reason;
	u8 *headpage;
	int ret;

	headpage = kmap_local_page(*rq->in);
	reason = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,
				min_t(unsigned int, rq->inputsize,
				      rq->sb->s_blocksize - rq->pageofs_in));
	kunmap_local(headpage);
	if (reason)
		return IS_ERR(reason) ? PTR_ERR(reason) : -EFSCORRUPTED;

	req = acomp_request_alloc(tfm);
	if (!req)
		return -ENOMEM;

	ret = sg_alloc_table_from_pages_segment(&st_src, rq->in, rq->inpages,
			rq->pageofs_in, rq->inputsize, UINT_MAX, GFP_KERNEL);
	if (ret < 0)
		goto failed_src_alloc;

	ret = sg_alloc_table_from_pages_segment(&st_dst, rq->out, rq->outpages,
			rq->pageofs_out, rq->outputsize, UINT_MAX, GFP_KERNEL);
	if (ret < 0)
		goto failed_dst_alloc;

	acomp_request_set_params(req, st_src.sgl,
				 st_dst.sgl, rq->inputsize, rq->outputsize);

	crypto_init_wait(&wait);
	acomp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				   crypto_req_done, &wait);

	ret = crypto_wait_req(crypto_acomp_decompress(req), &wait);
	if (ret) {
		erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
			  ret, rq->inputsize, rq->pageofs_in, rq->outputsize);
		ret = -EIO;
	}

	sg_free_table(&st_dst);
failed_dst_alloc:
	sg_free_table(&st_src);
failed_src_alloc:
	acomp_request_free(req);
	return ret;
}

struct z_erofs_crypto_engine {
	char *crypto_name;
	struct crypto_acomp *tfm;
};

static struct z_erofs_crypto_engine *z_erofs_crypto[Z_EROFS_COMPRESSION_MAX] = {
	[Z_EROFS_COMPRESSION_LZ4] = (struct z_erofs_crypto_engine[]) {
		{},
	},
	[Z_EROFS_COMPRESSION_LZMA] = (struct z_erofs_crypto_engine[]) {
		{},
	},
	[Z_EROFS_COMPRESSION_DEFLATE] = (struct z_erofs_crypto_engine[]) {
		{ .crypto_name = "qat_deflate", },
		{},
	},
	[Z_EROFS_COMPRESSION_ZSTD] = (struct z_erofs_crypto_engine[]) {
		{},
	},
};
static DECLARE_RWSEM(z_erofs_crypto_rwsem);

static struct crypto_acomp *z_erofs_crypto_get_engine(int alg)
{
	struct z_erofs_crypto_engine *e;

	for (e = z_erofs_crypto[alg]; e->crypto_name; ++e)
		if (e->tfm)
			return e->tfm;
	return NULL;
}

int z_erofs_crypto_decompress(struct z_erofs_decompress_req *rq,
			      struct page **pgpl)
{
	struct crypto_acomp *tfm;
	int i, err;

	down_read(&z_erofs_crypto_rwsem);
	tfm = z_erofs_crypto_get_engine(rq->alg);
	if (!tfm) {
		err = -EOPNOTSUPP;
		goto out;
	}

	for (i = 0; i < rq->outpages; i++) {
		struct page *const page = rq->out[i];
		struct page *victim;

		if (!page) {
			victim = __erofs_allocpage(pgpl, rq->gfp, true);
			if (!victim) {
				err = -ENOMEM;
				goto out;
			}
			set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);
			rq->out[i] = victim;
		}
	}
	err = __z_erofs_crypto_decompress(rq, tfm);
out:
	up_read(&z_erofs_crypto_rwsem);
	return err;
}

int z_erofs_crypto_enable_engine(const char *name, int len)
{
	struct z_erofs_crypto_engine *e;
	struct crypto_acomp *tfm;
	int alg;

	down_write(&z_erofs_crypto_rwsem);
	for (alg = 0; alg < Z_EROFS_COMPRESSION_MAX; ++alg) {
		for (e = z_erofs_crypto[alg]; e->crypto_name; ++e) {
			if (!strncmp(name, e->crypto_name, len)) {
				if (e->tfm)
					break;
				tfm = crypto_alloc_acomp(e->crypto_name, 0, 0);
				if (IS_ERR(tfm)) {
					up_write(&z_erofs_crypto_rwsem);
					return -EOPNOTSUPP;
				}
				e->tfm = tfm;
				break;
			}
		}
	}
	up_write(&z_erofs_crypto_rwsem);
	return 0;
}

void z_erofs_crypto_disable_all_engines(void)
{
	struct z_erofs_crypto_engine *e;
	int alg;

	down_write(&z_erofs_crypto_rwsem);
	for (alg = 0; alg < Z_EROFS_COMPRESSION_MAX; ++alg) {
		for (e = z_erofs_crypto[alg]; e->crypto_name; ++e) {
			if (!e->tfm)
				continue;
			crypto_free_acomp(e->tfm);
			e->tfm = NULL;
		}
	}
	up_write(&z_erofs_crypto_rwsem);
}

int z_erofs_crypto_show_engines(char *buf, int size, char sep)
{
	struct z_erofs_crypto_engine *e;
	int alg, len = 0;

	for (alg = 0; alg < Z_EROFS_COMPRESSION_MAX; ++alg) {
		for (e = z_erofs_crypto[alg]; e->crypto_name; ++e) {
			if (!e->tfm)
				continue;
			len += scnprintf(buf + len, size - len, "%s%c",
					 e->crypto_name, sep);
		}
	}
	return len;
}