VisionFive2 Linux kernel

author: Imre Deak <imre.deak@intel.com> 2013-02-27 17:02:57 -0800 committer: Linus Torvalds <torvalds@linux-foundation.org> 2013-02-27 19:10:10 -0800 commit: 4225fc8555a992c7f91d174ef424384d6781e144 parent: a321e91b6d73ed011ffceed384c40d2785cf723b

Commit Summary:

lib/scatterlist: use page iterator in the mapping iterator

Diffstat:

1 file changed, 22 insertions, 24 deletions

diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index a1d15647d7db..b83c144d731f 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -449,9 +449,7 @@ void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
 {
 	memset(miter, 0, sizeof(struct sg_mapping_iter));
 
-	miter->__sg = sgl;
-	miter->__nents = nents;
-	miter->__offset = 0;
+	__sg_page_iter_start(&miter->piter, sgl, nents, 0);
 	WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG)));
 	miter->__flags = flags;
 }
@@ -476,36 +474,35 @@ EXPORT_SYMBOL(sg_miter_start);
  */
 bool sg_miter_next(struct sg_mapping_iter *miter)
 {
-	unsigned int off, len;
-
-	/* check for end and drop resources from the last iteration */
-	if (!miter->__nents)
-		return false;
-
 	sg_miter_stop(miter);
 
-	/* get to the next sg if necessary.  __offset is adjusted by stop */
-	while (miter->__offset == miter->__sg->length) {
-		if (--miter->__nents) {
-			miter->__sg = sg_next(miter->__sg);
-			miter->__offset = 0;
-		} else
+	/*
+	 * Get to the next page if necessary.
+	 * __remaining, __offset is adjusted by sg_miter_stop
+	 */
+	if (!miter->__remaining) {
+		struct scatterlist *sg;
+		unsigned long pgoffset;
+
+		if (!__sg_page_iter_next(&miter->piter))
 			return false;
-	}
 
-	/* map the next page */
-	off = miter->__sg->offset + miter->__offset;
-	len = miter->__sg->length - miter->__offset;
+		sg = miter->piter.sg;
+		pgoffset = miter->piter.sg_pgoffset;
 
-	miter->page = nth_page(sg_page(miter->__sg), off >> PAGE_SHIFT);
-	off &= ~PAGE_MASK;
-	miter->length = min_t(unsigned int, len, PAGE_SIZE - off);
-	miter->consumed = miter->length;
+		miter->__offset = pgoffset ? 0 : sg->offset;
+		miter->__remaining = sg->offset + sg->length -
+				(pgoffset << PAGE_SHIFT) - miter->__offset;
+		miter->__remaining = min_t(unsigned long, miter->__remaining,
+					   PAGE_SIZE - miter->__offset);
+	}
+	miter->page = miter->piter.page;
+	miter->consumed = miter->length = miter->__remaining;
 
 	if (miter->__flags & SG_MITER_ATOMIC)
-		miter->addr = kmap_atomic(miter->page) + off;
+		miter->addr = kmap_atomic(miter->page) + miter->__offset;
 	else
-		miter->addr = kmap(miter->page) + off;
+		miter->addr = kmap(miter->page) + miter->__offset;
 
 	return true;
 }
@@ -532,6 +529,7 @@ void sg_miter_stop(struct sg_mapping_iter *miter)
 	/* drop resources from the last iteration */
 	if (miter->addr) {
 		miter->__offset += miter->consumed;
+		miter->__remaining -= miter->consumed;
 
 		if (miter->__flags & SG_MITER_TO_SG)
 			flush_kernel_dcache_page(miter->page);