X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=include%2Flinux%2Fscatterlist.h;h=cb3c8fe6acd776f55f78ca9cebe05028b8c7cf70;hb=9b1d6c8950021ab007608d455fc9c398ecd25476;hp=556ec1ea25746d51bfc8d2fe1f55c21272062eae;hpb=42dc2a3048247109b0a5ee6345226cbd3e4f6410;p=cascardo%2Flinux.git

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
@@ -285,6 +285,31 @@ 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
  *