lib/scatterlist: Fix mapping iterator when sg->offset is greater than PAGE_SIZE

[thirdparty/kernel/stable.git] / lib / scatterlist.c

diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 739dc9fe2c55ecce2777a498db03396673d5a9c3..f0757a67affe20eeecef87a2162cf5b87a9c88ab 100644 (file)
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -678,17 +678,18 @@ static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)
 {
        if (!miter->__remaining) {
                struct scatterlist *sg;
-               unsigned long pgoffset;
 
                if (!__sg_page_iter_next(&miter->piter))
                        return false;
 
                sg = miter->piter.sg;
-               pgoffset = miter->piter.sg_pgoffset;
 
-               miter->__offset = pgoffset ? 0 : sg->offset;
+               miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset;
+               miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT;
+               miter->__offset &= PAGE_SIZE - 1;
                miter->__remaining = sg->offset + sg->length -
-                               (pgoffset << PAGE_SHIFT) - miter->__offset;
+                                    (miter->piter.sg_pgoffset << PAGE_SHIFT) -
+                                    miter->__offset;
                miter->__remaining = min_t(unsigned long, miter->__remaining,
                                           PAGE_SIZE - miter->__offset);
        }