On Wed, Mar 05, 2025 at 06:11:30AM +0000, Yosry Ahmed wrote: > Use the new object read/write APIs instead of mapping APIs. > > On compress side, zpool_obj_write() is more concise and provides exactly > what zswap needs to write the compressed object to the zpool, instead of > map->copy->unmap. > > On the decompress side, zpool_obj_read_begin() is sleepable, which > allows avoiding the memcpy() for zsmalloc and slightly simplifying the > code by: > - Avoiding checking if the zpool driver is sleepable, reducing special > cases and shrinking the huge comment. > - Having a single zpool_obj_read_end() call rather than multiple > conditional zpool_unmap_handle() calls. > > The !virt_addr_valid() case can be removed in the future if the crypto > API supports kmap addresses or by using kmap_to_page(), completely > eliminating the memcpy() path in zswap_decompress(). This a step toward > that. In that spirit, opportunistically make the comment more specific > about the kmap case instead of generic non-linear addresses. This is the > only case that needs to be handled in practice, and the generic comment > makes it seem like a bigger problem that it actually is. > > Signed-off-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
