rslib: Simplify error path

The four error path labels in rs_init() can be reduced to one by allocating
the struct with kzalloc so the pointers in the struct are NULL and can be
unconditionally handed in to kfree() because they either point to an
allocation or are NULL.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NKees Cook <keescook@chromium.org>

lib/reed_solomon/reed_solomon.c

@@ -60,8 +60,7 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
 	struct rs_control *rs;
 	int i, j, sr, root, iprim;
 
-	/* Allocate the control structure */
-	rs = kmalloc(sizeof(*rs), gfp);
+	rs = kzalloc(sizeof(*rs), gfp);
 	if (!rs)
 		return NULL;
 
@@ -78,15 +77,15 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
 	/* Allocate the arrays */
 	rs->alpha_to = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
 	if (rs->alpha_to == NULL)
-		goto errrs;
+		goto err;
 
 	rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
 	if (rs->index_of == NULL)
-		goto erralp;
+		goto err;
 
 	rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), gfp);
 	if(rs->genpoly == NULL)
-		goto erridx;
+		goto err;
 
 	/* Generate Galois field lookup tables */
 	rs->index_of[0] = rs->nn;	/* log(zero) = -inf */
@@ -111,7 +110,7 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
 	}
 	/* If it's not primitive, exit */
 	if(sr != rs->alpha_to[0])
-		goto errpol;
+		goto err;
 
 	/* Find prim-th root of 1, used in decoding */
 	for(iprim = 1; (iprim % prim) != 0; iprim += rs->nn);
@@ -141,14 +140,10 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
 		rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
 	return rs;
 
-	/* Error exit */
-errpol:
+err:
 	kfree(rs->genpoly);
-erridx:
 	kfree(rs->index_of);
-erralp:
 	kfree(rs->alpha_to);
-errrs:
 	kfree(rs);
 	return NULL;
 }