/*
  * aead_edesc - s/w-extended aead descriptor
- * @src_nents: number of segments in input scatterlist
- * @dst_nents: number of segments in output scatterlist
+ * @src_nents: number of segments in input s/w scatterlist
+ * @dst_nents: number of segments in output s/w scatterlist
  * @sec4_sg_bytes: length of dma mapped sec4_sg space
  * @sec4_sg_dma: bus physical mapped address of h/w link table
  * @sec4_sg: pointer to h/w link table
 
 /*
  * ablkcipher_edesc - s/w-extended ablkcipher descriptor
- * @src_nents: number of segments in input scatterlist
- * @dst_nents: number of segments in output scatterlist
+ * @src_nents: number of segments in input s/w scatterlist
+ * @dst_nents: number of segments in output s/w scatterlist
  * @iv_dma: dma address of iv for checking continuity and link table
  * @sec4_sg_bytes: length of dma mapped sec4_sg space
  * @sec4_sg_dma: bus physical mapped address of h/w link table
                       int sec4_sg_bytes)
 {
        if (dst != src) {
-               dma_unmap_sg(dev, src, src_nents ? : 1, DMA_TO_DEVICE);
-               dma_unmap_sg(dev, dst, dst_nents ? : 1, DMA_FROM_DEVICE);
+               if (src_nents)
+                       dma_unmap_sg(dev, src, src_nents, DMA_TO_DEVICE);
+               dma_unmap_sg(dev, dst, dst_nents, DMA_FROM_DEVICE);
        } else {
-               dma_unmap_sg(dev, src, src_nents ? : 1, DMA_BIDIRECTIONAL);
+               dma_unmap_sg(dev, src, src_nents, DMA_BIDIRECTIONAL);
        }
 
        if (iv_dma)
        init_job_desc_shared(desc, ptr, len, HDR_SHARE_DEFER | HDR_REVERSE);
 
        if (all_contig) {
-               src_dma = sg_dma_address(req->src);
+               src_dma = edesc->src_nents ? sg_dma_address(req->src) : 0;
                in_options = 0;
        } else {
                src_dma = edesc->sec4_sg_dma;
        out_options = in_options;
 
        if (unlikely(req->src != req->dst)) {
-               if (!edesc->dst_nents) {
+               if (edesc->dst_nents == 1) {
                        dst_dma = sg_dma_address(req->dst);
                } else {
                        dst_dma = edesc->sec4_sg_dma +
        print_hex_dump(KERN_ERR, "presciv@"__stringify(__LINE__)": ",
                       DUMP_PREFIX_ADDRESS, 16, 4, req->info,
                       ivsize, 1);
-       printk(KERN_ERR "asked=%d, nbytes%d\n", (int)edesc->src_nents ? 100 : req->nbytes, req->nbytes);
+       pr_err("asked=%d, nbytes%d\n",
+              (int)edesc->src_nents > 1 ? 100 : req->nbytes, req->nbytes);
        dbg_dump_sg(KERN_ERR, "src    @"__stringify(__LINE__)": ",
                    DUMP_PREFIX_ADDRESS, 16, 4, req->src,
-                   edesc->src_nents ? 100 : req->nbytes, 1);
+                   edesc->src_nents > 1 ? 100 : req->nbytes, 1);
 #endif
 
        len = desc_len(sh_desc);
        append_seq_in_ptr(desc, src_dma, req->nbytes + ivsize, in_options);
 
        if (likely(req->src == req->dst)) {
-               if (!edesc->src_nents && iv_contig) {
+               if (edesc->src_nents == 1 && iv_contig) {
                        dst_dma = sg_dma_address(req->src);
                } else {
                        dst_dma = edesc->sec4_sg_dma +
                        out_options = LDST_SGF;
                }
        } else {
-               if (!edesc->dst_nents) {
+               if (edesc->dst_nents == 1) {
                        dst_dma = sg_dma_address(req->dst);
                } else {
                        dst_dma = edesc->sec4_sg_dma +
                       ivsize, 1);
        dbg_dump_sg(KERN_ERR, "src    @" __stringify(__LINE__) ": ",
                    DUMP_PREFIX_ADDRESS, 16, 4, req->src,
-                   edesc->src_nents ? 100 : req->nbytes, 1);
+                   edesc->src_nents > 1 ? 100 : req->nbytes, 1);
 #endif
 
        len = desc_len(sh_desc);
        init_job_desc_shared(desc, ptr, len, HDR_SHARE_DEFER | HDR_REVERSE);
 
-       if (!edesc->src_nents) {
+       if (edesc->src_nents == 1) {
                src_dma = sg_dma_address(req->src);
                in_options = 0;
        } else {
        int src_nents, dst_nents = 0;
        struct aead_edesc *edesc;
        int sgc;
-       bool all_contig = true;
-       int sec4_sg_index, sec4_sg_len = 0, sec4_sg_bytes;
+       int sec4_sg_index, sec4_sg_len, sec4_sg_bytes;
        unsigned int authsize = ctx->authsize;
 
        if (unlikely(req->dst != req->src)) {
-               src_nents = sg_count(req->src, req->assoclen + req->cryptlen);
+               src_nents = sg_nents_for_len(req->src, req->assoclen +
+                                            req->cryptlen);
                if (unlikely(src_nents < 0)) {
                        dev_err(jrdev, "Insufficient bytes (%d) in src S/G\n",
                                req->assoclen + req->cryptlen);
                        return ERR_PTR(src_nents);
                }
 
-               dst_nents = sg_count(req->dst,
-                                    req->assoclen + req->cryptlen +
-                                       (encrypt ? authsize : (-authsize)));
+               dst_nents = sg_nents_for_len(req->dst, req->assoclen +
+                                            req->cryptlen +
+                                               (encrypt ? authsize :
+                                                          (-authsize)));
                if (unlikely(dst_nents < 0)) {
                        dev_err(jrdev, "Insufficient bytes (%d) in dst S/G\n",
                                req->assoclen + req->cryptlen +
                        return ERR_PTR(dst_nents);
                }
        } else {
-               src_nents = sg_count(req->src,
-                                    req->assoclen + req->cryptlen +
-                                       (encrypt ? authsize : 0));
+               src_nents = sg_nents_for_len(req->src, req->assoclen +
+                                            req->cryptlen +
+                                            (encrypt ? authsize : 0));
                if (unlikely(src_nents < 0)) {
                        dev_err(jrdev, "Insufficient bytes (%d) in src S/G\n",
                                req->assoclen + req->cryptlen +
                }
        }
 
-       /* Check if data are contiguous. */
-       all_contig = !src_nents;
-       if (!all_contig)
-               sec4_sg_len = src_nents;
-
-       sec4_sg_len += dst_nents;
-
+       sec4_sg_len = src_nents > 1 ? src_nents : 0;
+       sec4_sg_len += dst_nents > 1 ? dst_nents : 0;
        sec4_sg_bytes = sec4_sg_len * sizeof(struct sec4_sg_entry);
 
        /* allocate space for base edesc and hw desc commands, link tables */
        }
 
        if (likely(req->src == req->dst)) {
-               sgc = dma_map_sg(jrdev, req->src, src_nents ? : 1,
-                                DMA_BIDIRECTIONAL);
+               sgc = dma_map_sg(jrdev, req->src, src_nents, DMA_BIDIRECTIONAL);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map source\n");
                        kfree(edesc);
                        return ERR_PTR(-ENOMEM);
                }
        } else {
-               sgc = dma_map_sg(jrdev, req->src, src_nents ? : 1,
-                                DMA_TO_DEVICE);
-               if (unlikely(!sgc)) {
-                       dev_err(jrdev, "unable to map source\n");
-                       kfree(edesc);
-                       return ERR_PTR(-ENOMEM);
+               /* Cover also the case of null (zero length) input data */
+               if (src_nents) {
+                       sgc = dma_map_sg(jrdev, req->src, src_nents,
+                                        DMA_TO_DEVICE);
+                       if (unlikely(!sgc)) {
+                               dev_err(jrdev, "unable to map source\n");
+                               kfree(edesc);
+                               return ERR_PTR(-ENOMEM);
+                       }
                }
 
-               sgc = dma_map_sg(jrdev, req->dst, dst_nents ? : 1,
-                                DMA_FROM_DEVICE);
+               sgc = dma_map_sg(jrdev, req->dst, dst_nents, DMA_FROM_DEVICE);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map destination\n");
-                       dma_unmap_sg(jrdev, req->src, src_nents ? : 1,
-                                    DMA_TO_DEVICE);
+                       dma_unmap_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
                        kfree(edesc);
                        return ERR_PTR(-ENOMEM);
                }
        edesc->dst_nents = dst_nents;
        edesc->sec4_sg = (void *)edesc + sizeof(struct aead_edesc) +
                         desc_bytes;
-       *all_contig_ptr = all_contig;
+       *all_contig_ptr = !(src_nents > 1);
 
        sec4_sg_index = 0;
-       if (!all_contig) {
+       if (src_nents > 1) {
                sg_to_sec4_sg_last(req->src, src_nents,
                              edesc->sec4_sg + sec4_sg_index, 0);
                sec4_sg_index += src_nents;
        }
-       if (dst_nents) {
+       if (dst_nents > 1) {
                sg_to_sec4_sg_last(req->dst, dst_nents,
                                   edesc->sec4_sg + sec4_sg_index, 0);
        }
        int src_nents, dst_nents = 0, sec4_sg_bytes;
        struct ablkcipher_edesc *edesc;
        dma_addr_t iv_dma = 0;
-       bool iv_contig = false;
+       bool in_contig;
        int sgc;
        int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
-       int sec4_sg_index;
+       int dst_sg_idx, sec4_sg_ents;
 
-       src_nents = sg_count(req->src, req->nbytes);
+       src_nents = sg_nents_for_len(req->src, req->nbytes);
        if (unlikely(src_nents < 0)) {
                dev_err(jrdev, "Insufficient bytes (%d) in src S/G\n",
                        req->nbytes);
        }
 
        if (req->dst != req->src) {
-               dst_nents = sg_count(req->dst, req->nbytes);
+               dst_nents = sg_nents_for_len(req->dst, req->nbytes);
                if (unlikely(dst_nents < 0)) {
                        dev_err(jrdev, "Insufficient bytes (%d) in dst S/G\n",
                                req->nbytes);
        }
 
        if (likely(req->src == req->dst)) {
-               sgc = dma_map_sg(jrdev, req->src, src_nents ? : 1,
-                                DMA_BIDIRECTIONAL);
+               sgc = dma_map_sg(jrdev, req->src, src_nents, DMA_BIDIRECTIONAL);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map source\n");
                        return ERR_PTR(-ENOMEM);
                }
        } else {
-               sgc = dma_map_sg(jrdev, req->src, src_nents ? : 1,
-                                DMA_TO_DEVICE);
+               sgc = dma_map_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map source\n");
                        return ERR_PTR(-ENOMEM);
                }
 
-               sgc = dma_map_sg(jrdev, req->dst, dst_nents ? : 1,
-                                DMA_FROM_DEVICE);
+               sgc = dma_map_sg(jrdev, req->dst, dst_nents, DMA_FROM_DEVICE);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map destination\n");
-                       dma_unmap_sg(jrdev, req->src, src_nents ? : 1,
-                                    DMA_TO_DEVICE);
+                       dma_unmap_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
                        return ERR_PTR(-ENOMEM);
                }
        }
                return ERR_PTR(-ENOMEM);
        }
 
-       /*
-        * Check if iv can be contiguous with source and destination.
-        * If so, include it. If not, create scatterlist.
-        */
-       if (!src_nents && iv_dma + ivsize == sg_dma_address(req->src))
-               iv_contig = true;
-       else
-               src_nents = src_nents ? : 1;
-       sec4_sg_bytes = ((iv_contig ? 0 : 1) + src_nents + dst_nents) *
-                       sizeof(struct sec4_sg_entry);
+       if (src_nents == 1 && iv_dma + ivsize == sg_dma_address(req->src)) {
+               in_contig = true;
+               sec4_sg_ents = 0;
+       } else {
+               in_contig = false;
+               sec4_sg_ents = 1 + src_nents;
+       }
+       dst_sg_idx = sec4_sg_ents;
+       sec4_sg_ents += dst_nents > 1 ? dst_nents : 0;
+       sec4_sg_bytes = sec4_sg_ents * sizeof(struct sec4_sg_entry);
 
        /* allocate space for base edesc and hw desc commands, link tables */
        edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes,
        edesc->sec4_sg = (void *)edesc + sizeof(struct ablkcipher_edesc) +
                         desc_bytes;
 
-       sec4_sg_index = 0;
-       if (!iv_contig) {
+       if (!in_contig) {
                dma_to_sec4_sg_one(edesc->sec4_sg, iv_dma, ivsize, 0);
                sg_to_sec4_sg_last(req->src, src_nents,
                                   edesc->sec4_sg + 1, 0);
-               sec4_sg_index += 1 + src_nents;
        }
 
-       if (dst_nents) {
+       if (dst_nents > 1) {
                sg_to_sec4_sg_last(req->dst, dst_nents,
-                       edesc->sec4_sg + sec4_sg_index, 0);
+                       edesc->sec4_sg + dst_sg_idx, 0);
        }
 
        edesc->sec4_sg_dma = dma_map_single(jrdev, edesc->sec4_sg,
                       sec4_sg_bytes, 1);
 #endif
 
-       *iv_contig_out = iv_contig;
+       *iv_contig_out = in_contig;
        return edesc;
 }
 
        int src_nents, dst_nents, sec4_sg_bytes;
        struct ablkcipher_edesc *edesc;
        dma_addr_t iv_dma = 0;
-       bool iv_contig = false;
+       bool out_contig;
        int sgc;
        int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
-       int sec4_sg_index;
+       int dst_sg_idx, sec4_sg_ents;
 
-       src_nents = sg_count(req->src, req->nbytes);
+       src_nents = sg_nents_for_len(req->src, req->nbytes);
        if (unlikely(src_nents < 0)) {
                dev_err(jrdev, "Insufficient bytes (%d) in src S/G\n",
                        req->nbytes);
        }
 
        if (likely(req->src == req->dst)) {
-               sgc = dma_map_sg(jrdev, req->src, src_nents ? : 1,
-                                DMA_BIDIRECTIONAL);
+               sgc = dma_map_sg(jrdev, req->src, src_nents, DMA_BIDIRECTIONAL);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map source\n");
                        return ERR_PTR(-ENOMEM);
 
                dst_nents = src_nents;
        } else {
-               sgc = dma_map_sg(jrdev, req->src, src_nents ? : 1,
-                                DMA_TO_DEVICE);
+               sgc = dma_map_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map source\n");
                        return ERR_PTR(-ENOMEM);
                }
 
-               dst_nents = sg_count(req->dst, req->nbytes);
+               dst_nents = sg_nents_for_len(req->dst, req->nbytes);
                if (unlikely(dst_nents < 0)) {
                        dev_err(jrdev, "Insufficient bytes (%d) in dst S/G\n",
                                req->nbytes);
                        return ERR_PTR(dst_nents);
                }
 
-               sgc = dma_map_sg(jrdev, req->dst, dst_nents ? : 1,
-                                DMA_FROM_DEVICE);
+               sgc = dma_map_sg(jrdev, req->dst, dst_nents, DMA_FROM_DEVICE);
                if (unlikely(!sgc)) {
                        dev_err(jrdev, "unable to map destination\n");
-                       dma_unmap_sg(jrdev, req->src, src_nents ? : 1,
-                                    DMA_TO_DEVICE);
+                       dma_unmap_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
                        return ERR_PTR(-ENOMEM);
                }
        }
                return ERR_PTR(-ENOMEM);
        }
 
-       if (!dst_nents && iv_dma + ivsize == sg_dma_address(req->dst))
-               iv_contig = true;
-       else
-               dst_nents = dst_nents ? : 1;
-       sec4_sg_bytes = ((iv_contig ? 0 : 1) + src_nents + dst_nents) *
-                       sizeof(struct sec4_sg_entry);
+       sec4_sg_ents = src_nents > 1 ? src_nents : 0;
+       dst_sg_idx = sec4_sg_ents;
+       if (dst_nents == 1 && iv_dma + ivsize == sg_dma_address(req->dst)) {
+               out_contig = true;
+       } else {
+               out_contig = false;
+               sec4_sg_ents += 1 + dst_nents;
+       }
 
        /* allocate space for base edesc and hw desc commands, link tables */
+       sec4_sg_bytes = sec4_sg_ents * sizeof(struct sec4_sg_entry);
        edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes,
                        GFP_DMA | flags);
        if (!edesc) {
        edesc->sec4_sg = (void *)edesc + sizeof(struct ablkcipher_edesc) +
                         desc_bytes;
 
-       sec4_sg_index = 0;
-       if (src_nents) {
+       if (src_nents > 1)
                sg_to_sec4_sg_last(req->src, src_nents, edesc->sec4_sg, 0);
-               sec4_sg_index += src_nents;
-       }
 
-       if (!iv_contig) {
-               dma_to_sec4_sg_one(edesc->sec4_sg + sec4_sg_index,
+       if (!out_contig) {
+               dma_to_sec4_sg_one(edesc->sec4_sg + dst_sg_idx,
                                   iv_dma, ivsize, 0);
-               sec4_sg_index += 1;
                sg_to_sec4_sg_last(req->dst, dst_nents,
-                                  edesc->sec4_sg + sec4_sg_index, 0);
+                                  edesc->sec4_sg + dst_sg_idx + 1, 0);
        }
 
        edesc->sec4_sg_dma = dma_map_single(jrdev, edesc->sec4_sg,
                       sec4_sg_bytes, 1);
 #endif
 
-       *iv_contig_out = iv_contig;
+       *iv_contig_out = out_contig;
        return edesc;
 }