On Fri, Feb 28, 2025 at 04:13:08PM +0800, Herbert Xu wrote:
>
> I'll respin this.
FWIW this is what the interface looks like. Does it look OK?
Longer term hardware offload drivers should handle these non-DMA
pointers directly by having their own buffers. For the time being
I'm simply redirecting these to a software fallback.
diff --git a/mm/zswap.c b/mm/zswap.c
index 2b5a2398a9be..2fd241c65f80 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -994,30 +994,16 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio)
acomp_ctx = acomp_ctx_get_cpu_lock(entry->pool);
src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO);
- /*
- * If zpool_map_handle is atomic, we cannot reliably utilize its mapped buffer
- * to do crypto_acomp_decompress() which might sleep. In such cases, we must
- * resort to copying the buffer to a temporary one.
- * Meanwhile, zpool_map_handle() might return a non-linearly mapped buffer,
- * such as a kmap address of high memory or even ever a vmap address.
- * However, sg_init_one is only equipped to handle linearly mapped low memory.
- * In such cases, we also must copy the buffer to a temporary and lowmem one.
- */
- if ((acomp_ctx->is_sleepable && !zpool_can_sleep_mapped(zpool)) ||
- !virt_addr_valid(src)) {
- memcpy(acomp_ctx->buffer, src, entry->length);
- src = acomp_ctx->buffer;
- zpool_unmap_handle(zpool, entry->handle);
- }
-
dst = kmap_local_folio(folio, 0);
- acomp_request_set_virt(acomp_ctx->req, src, dst, entry->length, PAGE_SIZE);
+ if (!zpool_can_sleep_mapped(zpool) || !virt_addr_valid(src))
+ acomp_request_set_nondma(acomp_ctx->req, src, dst, entry->length, PAGE_SIZE);
+ else
+ acomp_request_set_virt(acomp_ctx->req, src, dst, entry->length, PAGE_SIZE);
BUG_ON(crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait));
kunmap_local(dst);
BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE);
- if (src != acomp_ctx->buffer)
- zpool_unmap_handle(zpool, entry->handle);
+ zpool_unmap_handle(zpool, entry->handle);
acomp_ctx_put_unlock(acomp_ctx);
}
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
