[PATCH 1/2] lib/scatterlist: export sg_miter_skip()

From: Ming Lei
Date: Tue Oct 29 2013 - 12:07:57 EST

sg_copy_buffer() can't meet demand for some drrivers(such usb
mass storage), so we have to use the sg_miter_* APIs to access
sg buffer, then need export sg_miter_skip() for these drivers.

The API is needed for converting to sg_miter_* APIs in USB storage
driver for accessing sg buffer.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>,
Cc: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>,
Cc: Tejun Heo <tj@xxxxxxxxxx>,
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
include/linux/scatterlist.h | 1 +
lib/scatterlist.c | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index adae88f..a964f72 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -345,6 +345,7 @@ struct sg_mapping_iter {

void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
unsigned int nents, unsigned int flags);
+bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset);
bool sg_miter_next(struct sg_mapping_iter *miter);
void sg_miter_stop(struct sg_mapping_iter *miter);

diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index d16fa29..3a8e8e8 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -495,7 +495,7 @@ static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)
* true if @miter contains the valid mapping. false if end of sg
* list is reached.
-static bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)
+bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)

@@ -513,6 +513,7 @@ static bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)

return true;

* sg_miter_next - proceed mapping iterator to the next mapping

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