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authorRichard Weinberger <richard@nod.at>2015-01-10 22:52:13 +0100
committerRichard Weinberger <richard@nod.at>2015-01-28 16:04:26 +0100
commit9ff08979e17423f0f691c1d76f35dfec72a5e459 (patch)
treebba6c2556e642bfae792983766d3f07652f9714c /include
parent892abde56c1c5a62d49d8b70c73e5d388e74345d (diff)
UBI: Add initial support for scatter gather
Adds a new set of functions to deal with scatter gather. ubi_eba_read_leb_sg() will read from a LEB into a scatter gather list. The new data structure struct ubi_sgl will be used within UBI to hold the scatter gather list itself and metadata to have a cursor within the list. Signed-off-by: Richard Weinberger <richard@nod.at> Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mtd/ubi.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h
index 8fa2753316e8..1e271cb559cd 100644
--- a/include/linux/mtd/ubi.h
+++ b/include/linux/mtd/ubi.h
@@ -23,12 +23,19 @@
#include <linux/ioctl.h>
#include <linux/types.h>
+#include <linux/scatterlist.h>
#include <mtd/ubi-user.h>
/* All voumes/LEBs */
#define UBI_ALL -1
/*
+ * Maximum number of scatter gather list entries,
+ * we use only 64 to have a lower memory foot print.
+ */
+#define UBI_MAX_SG_COUNT 64
+
+/*
* enum ubi_open_mode - UBI volume open mode constants.
*
* UBI_READONLY: read-only mode
@@ -119,6 +126,35 @@ struct ubi_volume_info {
};
/**
+ * struct ubi_sgl - UBI scatter gather list data structure.
+ * @list_pos: current position in @sg[]
+ * @page_pos: current position in @sg[@list_pos]
+ * @sg: the scatter gather list itself
+ *
+ * ubi_sgl is a wrapper around a scatter list which keeps track of the
+ * current position in the list and the current list item such that
+ * it can be used across multiple ubi_leb_read_sg() calls.
+ */
+struct ubi_sgl {
+ int list_pos;
+ int page_pos;
+ struct scatterlist sg[UBI_MAX_SG_COUNT];
+};
+
+/**
+ * ubi_sgl_init - initialize an UBI scatter gather list data structure.
+ * @usgl: the UBI scatter gather struct itself
+ *
+ * Please note that you still have to use sg_init_table() or any adequate
+ * function to initialize the unterlaying struct scatterlist.
+ */
+static inline void ubi_sgl_init(struct ubi_sgl *usgl)
+{
+ usgl->list_pos = 0;
+ usgl->page_pos = 0;
+}
+
+/**
* struct ubi_device_info - UBI device description data structure.
* @ubi_num: ubi device number
* @leb_size: logical eraseblock size on this UBI device
@@ -213,6 +249,8 @@ int ubi_unregister_volume_notifier(struct notifier_block *nb);
void ubi_close_volume(struct ubi_volume_desc *desc);
int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
int len, int check);
+int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
+ int offset, int len, int check);
int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
int offset, int len);
int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
@@ -233,4 +271,14 @@ static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
{
return ubi_leb_read(desc, lnum, buf, offset, len, 0);
}
+
+/*
+ * This function is the same as the 'ubi_leb_read_sg()' function, but it does
+ * not provide the checking capability.
+ */
+static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum,
+ struct ubi_sgl *sgl, int offset, int len)
+{
+ return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0);
+}
#endif /* !__LINUX_UBI_H__ */