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);