On Tue, Dec 12, 2023 at 8:18 PM Chengming Zhou
<zhouchengming@xxxxxxxxxxxxx> wrote:
>
> The zswap_load() and zswap_writeback_entry() have the same part that
> decompress the data from zswap_entry to page, so refactor out the
> common part as __zswap_load(entry, page).
>
> Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
> Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
On a second look, there a few nits here.
First I think it makes more sense to move this refactoring ahead of
reusing destmem. Right now, we add the destmem reuse to zswap_load()
only, then we do the refactor and zswap_writeback_entry() gets it
automatically, so there is a slight change coming to
zswap_writeback_entry() hidden in the refactoring patch.
Let's refactor out __zswap_load() first, then reuse destmem in it.
> ---
> mm/zswap.c | 107 ++++++++++++++++++++++---------------------------------------
> 1 file changed, 38 insertions(+), 69 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index fa186945010d..2f095c919a5c 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1392,6 +1392,41 @@ static int zswap_enabled_param_set(const char *val,
> return ret;
> }
>
> +static void __zswap_load(struct zswap_entry *entry, struct page *page)
> +{
> + struct scatterlist input, output;
> + unsigned int dlen = PAGE_SIZE;
> + struct crypto_acomp_ctx *acomp_ctx;
> + struct zpool *zpool;
> + u8 *src;
> + int ret;
> +
> + acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
> + mutex_lock(acomp_ctx->mutex);
> +
> + zpool = zswap_find_zpool(entry);
> + src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO);
> + if (!zpool_can_sleep_mapped(zpool)) {
> + memcpy(acomp_ctx->dstmem, src, entry->length);
> + src = acomp_ctx->dstmem;
> + zpool_unmap_handle(zpool, entry->handle);
> + }
> +
> + sg_init_one(&input, src, entry->length);
> + sg_init_table(&output, 1);
> + sg_set_page(&output, page, PAGE_SIZE, 0);
> + acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, dlen);
We should pass PAGE_SIZE here directly, BUG_ON(acomp_ctx->req->dlen)
below, and remove the dlen variable.
> + ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait);
We should just BUG_ON() here directly an remove the ret variable.
