[PATCH RFC 31/35] crypto: remove nth_page() usage within SG entry

[David Hildenbrand]

It's no longer required to use nth_page() when iterating pages within a
single SG entry, so let's drop the nth_page() usage.

Cc: Herbert Xu <herbert at gondor.apana.org.au>
Cc: "David S. Miller" <davem at davemloft.net>
Signed-off-by: David Hildenbrand <david at redhat.com>
---
 crypto/ahash.c               | 4 ++--
 crypto/scompress.c           | 8 ++++----
 include/crypto/scatterwalk.h | 4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/crypto/ahash.c b/crypto/ahash.c
index a227793d2c5b5..a9f757224a223 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -88,7 +88,7 @@ static int hash_walk_new_entry(struct crypto_hash_walk *walk)
 
 	sg = walk->sg;
 	walk->offset = sg->offset;
-	walk->pg = nth_page(sg_page(walk->sg), (walk->offset >> PAGE_SHIFT));
+	walk->pg = sg_page(walk->sg) + walk->offset / PAGE_SIZE;
 	walk->offset = offset_in_page(walk->offset);
 	walk->entrylen = sg->length;
 
@@ -226,7 +226,7 @@ int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
 	if (!IS_ENABLED(CONFIG_HIGHMEM))
 		return crypto_shash_digest(desc, data, nbytes, req->result);
 
-	page = nth_page(page, offset >> PAGE_SHIFT);
+	page += offset / PAGE_SIZE;
 	offset = offset_in_page(offset);
 
 	if (nbytes > (unsigned int)PAGE_SIZE - offset)
diff --git a/crypto/scompress.c b/crypto/scompress.c
index c651e7f2197a9..1a7ed8ae65b07 100644
--- a/crypto/scompress.c
+++ b/crypto/scompress.c
@@ -198,7 +198,7 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
 		} else
 			return -ENOSYS;
 
-		dpage = nth_page(dpage, doff / PAGE_SIZE);
+		dpage += doff / PAGE_SIZE;
 		doff = offset_in_page(doff);
 
 		n = (dlen - 1) / PAGE_SIZE;
@@ -220,12 +220,12 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
 			} else
 				break;
 
-			spage = nth_page(spage, soff / PAGE_SIZE);
+			spage = spage + soff / PAGE_SIZE;
 			soff = offset_in_page(soff);
 
 			n = (slen - 1) / PAGE_SIZE;
 			n += (offset_in_page(slen - 1) + soff) / PAGE_SIZE;
-			if (PageHighMem(nth_page(spage, n)) &&
+			if (PageHighMem(spage + n) &&
 			    size_add(soff, slen) > PAGE_SIZE)
 				break;
 			src = kmap_local_page(spage) + soff;
@@ -270,7 +270,7 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
 			if (dlen <= PAGE_SIZE)
 				break;
 			dlen -= PAGE_SIZE;
-			dpage = nth_page(dpage, 1);
+			dpage++;
 		}
 	}
 
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 15ab743f68c8f..cdf8497d19d27 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -159,7 +159,7 @@ static inline void scatterwalk_map(struct scatter_walk *walk)
 	if (IS_ENABLED(CONFIG_HIGHMEM)) {
 		struct page *page;
 
-		page = nth_page(base_page, offset >> PAGE_SHIFT);
+		page = base_page + offset / PAGE_SIZE;
 		offset = offset_in_page(offset);
 		addr = kmap_local_page(page) + offset;
 	} else {
@@ -259,7 +259,7 @@ static inline void scatterwalk_done_dst(struct scatter_walk *walk,
 		end += (offset_in_page(offset) + offset_in_page(nbytes) +
 			PAGE_SIZE - 1) >> PAGE_SHIFT;
 		for (i = start; i < end; i++)
-			flush_dcache_page(nth_page(base_page, i));
+			flush_dcache_page(base_page + i);
 	}
 	scatterwalk_advance(walk, nbytes);
 }
-- 
2.50.1