diff options
Diffstat (limited to 'include/linux/scatterlist.h')
| -rw-r--r-- | include/linux/scatterlist.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 556ec1ea2574..cb3c8fe6acd7 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -286,6 +286,31 @@ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) /* + * The maximum number of SG segments that we will put inside a + * scatterlist (unless chaining is used). Should ideally fit inside a + * single page, to avoid a higher order allocation. We could define this + * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The + * minimum value is 32 + */ +#define SG_CHUNK_SIZE 128 + +/* + * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit + * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. + */ +#ifdef CONFIG_ARCH_HAS_SG_CHAIN +#define SG_MAX_SEGMENTS 2048 +#else +#define SG_MAX_SEGMENTS SG_CHUNK_SIZE +#endif + +#ifdef CONFIG_SG_POOL +void sg_free_table_chained(struct sg_table *table, bool first_chunk); +int sg_alloc_table_chained(struct sg_table *table, int nents, + struct scatterlist *first_chunk); +#endif + +/* * sg page iterator * * Iterates over sg entries page-by-page. On each successful iteration, |