On Mon, Dec 28, 2020 at 06:49:55PM -0500, Douglas Gilbert wrote:
> The existing sg_zero_buffer() function is a bit restrictive. For
> example protection information (PI) blocks are usually initialized
> to 0xff bytes. As its name suggests sgl_memset() is modelled on
> memset(). One difference is the type of the val argument which is
> u8 rather than int. Plus it returns the number of bytes (over)written.
>
> Change implementation of sg_zero_buffer() to call this new function.
>
> Reviewed-by: Bodo Stroesser <bostroesser@xxxxxxxxx>
> Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
> include/linux/scatterlist.h | 3 ++
> lib/scatterlist.c | 65 +++++++++++++++++++++++++------------
> 2 files changed, 48 insertions(+), 20 deletions(-)
>
> diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
> index 71be65f9ebb5..70d3f1f73df1 100644
> +++ b/include/linux/scatterlist.h
> @@ -333,6 +333,9 @@ bool sgl_compare_sgl_idx(struct scatterlist *x_sgl, unsigned int x_nents, off_t
> struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip,
> size_t n_bytes, size_t *miscompare_idx);
>
> +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip,
> + u8 val, size_t n_bytes);
> +
> /*
> * Maximum number of entries that will be allocated in one piece, if
> * a list larger than this is required then chaining will be utilized.
> diff --git a/lib/scatterlist.c b/lib/scatterlist.c
> index 9332365e7eb6..f06614a880c8 100644
> +++ b/lib/scatterlist.c
> @@ -1038,26 +1038,7 @@ EXPORT_SYMBOL(sg_pcopy_to_buffer);
> size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
> size_t buflen, off_t skip)
> {
> - unsigned int offset = 0;
> - struct sg_mapping_iter miter;
> - unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG;
> -
> - sg_miter_start(&miter, sgl, nents, sg_flags);
> -
> - if (!sg_miter_skip(&miter, skip))
> - return false;
> -
> - while (offset < buflen && sg_miter_next(&miter)) {
> - unsigned int len;
> -
> - len = min(miter.length, buflen - offset);
> - memset(miter.addr, 0, len);
> -
> - offset += len;
> - }
> -
> - sg_miter_stop(&miter);
> - return offset;
> + return sgl_memset(sgl, nents, skip, 0, buflen);
> }
> EXPORT_SYMBOL(sg_zero_buffer);
May as well make this one liner a static inline in the header. Just
rename this function to sgl_memset so the diff is clearer
Jason
