| Message ID | 20180330002100.5724-2-bhole_prashant_q7@lab.ntt.co.jp |
|---|---|
| State | Accepted, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | sockmap: fix sg api usage | expand |
On 03/29/2018 05:20 PM, Prashant Bhole wrote: > sg_init_marker initializes sg_magic in the sg table and calls > sg_mark_end() on the last entry of the table. This can be useful to > avoid memset in sg_init_table() when scatterlist is already zeroed out > > For example: when scatterlist is embedded inside other struct and that > container struct is zeroed out > > Suggested-by: Daniel Borkmann <daniel@iogearbox.net> > Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> > --- Acked-by: John Fastabend <john.fastabend@gmail.com>
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 22b2131bcdcd..aa5d4eb725f5 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -248,6 +248,24 @@ static inline void *sg_virt(struct scatterlist *sg) return page_address(sg_page(sg)) + sg->offset; } +/** + * sg_init_marker - Initialize markers in sg table + * @sgl: The SG table + * @nents: Number of entries in table + * + **/ +static inline void sg_init_marker(struct scatterlist *sgl, + unsigned int nents) +{ +#ifdef CONFIG_DEBUG_SG + unsigned int i; + + for (i = 0; i < nents; i++) + sgl[i].sg_magic = SG_MAGIC; +#endif + sg_mark_end(&sgl[nents - 1]); +} + int sg_nents(struct scatterlist *sg); int sg_nents_for_len(struct scatterlist *sg, u64 len); struct scatterlist *sg_next(struct scatterlist *); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 53728d391d3a..06dad7a072fd 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -132,14 +132,7 @@ EXPORT_SYMBOL(sg_last); void sg_init_table(struct scatterlist *sgl, unsigned int nents) { memset(sgl, 0, sizeof(*sgl) * nents); -#ifdef CONFIG_DEBUG_SG - { - unsigned int i; - for (i = 0; i < nents; i++) - sgl[i].sg_magic = SG_MAGIC; - } -#endif - sg_mark_end(&sgl[nents - 1]); + sg_init_marker(sgl, nents); } EXPORT_SYMBOL(sg_init_table);
sg_init_marker initializes sg_magic in the sg table and calls sg_mark_end() on the last entry of the table. This can be useful to avoid memset in sg_init_table() when scatterlist is already zeroed out For example: when scatterlist is embedded inside other struct and that container struct is zeroed out Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> --- include/linux/scatterlist.h | 18 ++++++++++++++++++ lib/scatterlist.c | 9 +-------- 2 files changed, 19 insertions(+), 8 deletions(-)