3 files changed, 29 insertions, 6 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index a001ba711cca..c03a78ee26cd 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2300,7 +2300,7 @@ queue_full:
 
 void target_free_sgl(struct scatterlist *sgl, int nents)
 {
-        sgl_free(sgl);
+        sgl_free_n_order(sgl, nents, 0);
 }
 EXPORT_SYMBOL(target_free_sgl);
 
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index b8a7c1d1dbe3..22b2131bcdcd 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -282,6 +282,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length,
                                     gfp_t gfp, unsigned int *nent_p);
 struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
                               unsigned int *nent_p);
+void sgl_free_n_order(struct scatterlist *sgl, int nents, int order);
 void sgl_free_order(struct scatterlist *sgl, int order);
 void sgl_free(struct scatterlist *sgl);
 #endif /* CONFIG_SGL_ALLOC */
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 9afc9b432083..53728d391d3a 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -512,7 +512,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length,
         if (!sgl)
                 return NULL;
 
-        sg_init_table(sgl, nent);
+        sg_init_table(sgl, nalloc);
         sg = sgl;
         while (length) {
                 elem_len = min_t(u64, length, PAGE_SIZE << order);
@@ -526,7 +526,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length,
                 length -= elem_len;
                 sg = sg_next(sg);
         }
-        WARN_ON_ONCE(sg);
+        WARN_ONCE(length, "length = %lld\n", length);
         if (nent_p)
                 *nent_p = nent;
         return sgl;
@@ -549,22 +549,44 @@ struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
 EXPORT_SYMBOL(sgl_alloc);
 
 /**
- * sgl_free_order - free a scatterlist and its pages
+ * sgl_free_n_order - free a scatterlist and its pages
  * @sgl: Scatterlist with one or more elements
+ * @nents: Maximum number of elements to free
  * @order: Second argument for __free_pages()
+ *
+ * Notes:
+ * - If several scatterlists have been chained and each chain element is
+ *   freed separately then it's essential to set nents correctly to avoid that a
+ *   page would get freed twice.
+ * - All pages in a chained scatterlist can be freed at once by setting @nents
+ *   to a high number.
  */
-void sgl_free_order(struct scatterlist *sgl, int order)
+void sgl_free_n_order(struct scatterlist *sgl, int nents, int order)
 {
         struct scatterlist *sg;
         struct page *page;
+        int i;
 
-        for (sg = sgl; sg; sg = sg_next(sg)) {
+        for_each_sg(sgl, sg, nents, i) {
+                if (!sg)
+                        break;
                 page = sg_page(sg);
                 if (page)
                         __free_pages(page, order);
         }
         kfree(sgl);
 }
+EXPORT_SYMBOL(sgl_free_n_order);
+
+/**
+ * sgl_free_order - free a scatterlist and its pages
+ * @sgl: Scatterlist with one or more elements
+ * @order: Second argument for __free_pages()
+ */
+void sgl_free_order(struct scatterlist *sgl, int order)
+{
+        sgl_free_n_order(sgl, INT_MAX, order);
+}
 EXPORT_SYMBOL(sgl_free_order);
 
 /**