Re: [PATCH] zsmalloc: introduce SG-list based object read API

[Herbert Xu]

On Tue, Jan 13, 2026 at 12:46:45PM +0900, Sergey Senozhatsky wrote:
> Currently, zsmalloc performs address linearization on read
> (which sometimes requires memcpy() to a local buffer).
> Not all zsmalloc users need a linear address. For example,
> Crypto API supports SG-list, performing linearization under
> the hood, if needed. In addition, some compressors can have
> native SG-list support, completely avoiding the linearization
> step.
> 
> Provide an SG-list based zsmalloc read API:
> - zs_obj_read_sg_begin()
> - zs_obj_read_sg_end()
> 
> This API allows callers to obtain an SG representation
> of the object (one entry for objects that are contained
> in a single page and two entries for spanning objects),
> avoiding the need for a bounce buffer and memcpy.
> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> ---
>  include/linux/zsmalloc.h |  4 +++
>  mm/zsmalloc.c            | 65 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 69 insertions(+)

Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

Thanks,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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