diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index 350abaf..9c6f6b9 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -81,7 +81,7 @@
 {
 	const uint8_t *buffer = xbuffer;
 	int i, j;
-	unsigned nbits, nbytes, nlimbs, nread = 0;
+	unsigned nbits, nbytes, nlimbs;
 	mpi_limb_t a;
 	MPI val = NULL;
 
@@ -94,9 +94,14 @@
 		return ERR_PTR(-EINVAL);
 	}
 	buffer += 2;
-	nread = 2;
 
 	nbytes = DIV_ROUND_UP(nbits, 8);
+	if (nbytes + 2 > *ret_nread) {
+		printk("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
+				*ret_nread + 1, *ret_nread);
+		return ERR_PTR(-EINVAL);
+	}
+
 	nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
 	val = mpi_alloc(nlimbs);
 	if (!val)
@@ -109,12 +114,6 @@
 	for (; j > 0; j--) {
 		a = 0;
 		for (; i < BYTES_PER_MPI_LIMB; i++) {
-			if (++nread > *ret_nread) {
-				printk
-				    ("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
-				     nread, *ret_nread);
-				goto leave;
-			}
 			a <<= 8;
 			a |= *buffer++;
 		}
@@ -122,8 +121,7 @@
 		val->d[j - 1] = a;
 	}
 
-leave:
-	*ret_nread = nread;
+	*ret_nread = nbytes + 2;
 	return val;
 }
 EXPORT_SYMBOL_GPL(mpi_read_from_buffer);