1 files changed, 50 insertions, 36 deletions

diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index 7150e5c23604..c6272ae2015e 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -21,6 +21,7 @@
 #include <linux/bitops.h>
 #include <linux/count_zeros.h>
 #include <linux/byteorder/generic.h>
+#include <linux/scatterlist.h>
 #include <linux/string.h>
 #include "mpi-internal.h"
 
@@ -255,7 +256,9 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned nbytes,
 #error please implement for this limb size.
 #endif
 	unsigned int n = mpi_get_size(a);
+	struct sg_mapping_iter miter;
 	int i, x, buf_len;
+	int nents;
 
 	if (sign)
 		*sign = a->sign;
@@ -263,23 +266,27 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned nbytes,
 	if (nbytes < n)
 		return -EOVERFLOW;
 
-	buf_len = sgl->length;
-	p2 = sg_virt(sgl);
+	nents = sg_nents_for_len(sgl, nbytes);
+	if (nents < 0)
+		return -EINVAL;
 
-	while (nbytes > n) {
-		if (!buf_len) {
-			sgl = sg_next(sgl);
-			if (!sgl)
-				return -EINVAL;
-			buf_len = sgl->length;
-			p2 = sg_virt(sgl);
-		}
+	sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC | SG_MITER_TO_SG);
+	sg_miter_next(&miter);
+	buf_len = miter.length;
+	p2 = miter.addr;
 
+	while (nbytes > n) {
 		i = min_t(unsigned, nbytes - n, buf_len);
 		memset(p2, 0, i);
 		p2 += i;
-		buf_len -= i;
 		nbytes -= i;
+
+		buf_len -= i;
+		if (!buf_len) {
+			sg_miter_next(&miter);
+			buf_len = miter.length;
+			p2 = miter.addr;
+		}
 	}
 
 	for (i = a->nlimbs - 1; i >= 0; i--) {
@@ -293,17 +300,16 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned nbytes,
 		p = (u8 *)&alimb;
 
 		for (x = 0; x < sizeof(alimb); x++) {
-			if (!buf_len) {
-				sgl = sg_next(sgl);
-				if (!sgl)
-					return -EINVAL;
-				buf_len = sgl->length;
-				p2 = sg_virt(sgl);
-			}
 			*p2++ = *p++;
-			buf_len--;
+			if (!--buf_len) {
+				sg_miter_next(&miter);
+				buf_len = miter.length;
+				p2 = miter.addr;
+			}
 		}
 	}
+
+	sg_miter_stop(&miter);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mpi_write_to_sgl);
@@ -323,19 +329,23 @@ EXPORT_SYMBOL_GPL(mpi_write_to_sgl);
  */
 MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
 {
-	struct scatterlist *sg;
-	int x, i, j, z, lzeros, ents;
+	struct sg_mapping_iter miter;
 	unsigned int nbits, nlimbs;
+	int x, j, z, lzeros, ents;
+	unsigned int len;
+	const u8 *buff;
 	mpi_limb_t a;
 	MPI val = NULL;
 
-	lzeros = 0;
-	ents = sg_nents(sgl);
+	ents = sg_nents_for_len(sgl, nbytes);
+	if (ents < 0)
+		return NULL;
 
-	for_each_sg(sgl, sg, ents, i) {
-		const u8 *buff = sg_virt(sg);
-		int len = sg->length;
+	sg_miter_start(&miter, sgl, ents, SG_MITER_ATOMIC | SG_MITER_FROM_SG);
 
+	lzeros = 0;
+	len = 0;
+	while (nbytes > 0) {
 		while (len && !*buff) {
 			lzeros++;
 			len--;
@@ -345,12 +355,14 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
 		if (len && *buff)
 			break;
 
-		ents--;
+		sg_miter_next(&miter);
+		buff = miter.addr;
+		len = miter.length;
+
 		nbytes -= lzeros;
 		lzeros = 0;
 	}
 
-	sgl = sg;
 	nbytes -= lzeros;
 	nbits = nbytes * 8;
 	if (nbits > MAX_EXTERN_MPI_BITS) {
@@ -359,8 +371,7 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
 	}
 
 	if (nbytes > 0)
-		nbits -= count_leading_zeros(*(u8 *)(sg_virt(sgl) + lzeros)) -
-			(BITS_PER_LONG - 8);
+		nbits -= count_leading_zeros(*buff) - (BITS_PER_LONG - 8);
 
 	nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
 	val = mpi_alloc(nlimbs);
@@ -379,21 +390,24 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
 	z = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
 	z %= BYTES_PER_MPI_LIMB;
 
-	for_each_sg(sgl, sg, ents, i) {
-		const u8 *buffer = sg_virt(sg) + lzeros;
-		int len = sg->length - lzeros;
-
+	for (;;) {
 		for (x = 0; x < len; x++) {
 			a <<= 8;
-			a |= *buffer++;
+			a |= *buff++;
 			if (((z + x + 1) % BYTES_PER_MPI_LIMB) == 0) {
 				val->d[j--] = a;
 				a = 0;
 			}
 		}
 		z += x;
-		lzeros = 0;
+
+		if (!sg_miter_next(&miter))
+			break;
+
+		buff = miter.addr;
+		len = miter.length;
 	}
+
 	return val;
 }
 EXPORT_SYMBOL_GPL(mpi_read_raw_from_sgl);