crypto: hisilicon - Fix double free in sec_free_hw_sgl()

There are two problems in sec_free_hw_sgl():

First, when sgl_current->next is valid, @hw_sgl will be freed in the
first loop, but it free again after the loop.

Second, sgl_current and sgl_current->next_sgl is not match when
dma_pool_free() is invoked, the third parameter should be the dma
address of sgl_current, but sgl_current->next_sgl is the dma address
of next chain, so use sgl_current->next_sgl is wrong.

Fix this by deleting the last dma_pool_free() in sec_free_hw_sgl(),
modifying the condition for while loop, and matching the address for
dma_pool_free().

Fixes: 915e4e84 ("crypto: hisilicon - SEC security accelerator driver")
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/hisilicon/sec/sec_algs.c

@@ -215,17 +215,18 @@ static void sec_free_hw_sgl(struct sec_hw_sgl *hw_sgl,
 			    dma_addr_t psec_sgl, struct sec_dev_info *info)
 {
 	struct sec_hw_sgl *sgl_current, *sgl_next;
+	dma_addr_t sgl_next_dma;
 
-	if (!hw_sgl)
-		return;
 	sgl_current = hw_sgl;
-	while (sgl_current->next) {
+	while (sgl_current) {
 		sgl_next = sgl_current->next;
-		dma_pool_free(info->hw_sgl_pool, sgl_current,
-			      sgl_current->next_sgl);
+		sgl_next_dma = sgl_current->next_sgl;
+
+		dma_pool_free(info->hw_sgl_pool, sgl_current, psec_sgl);
+
 		sgl_current = sgl_next;
+		psec_sgl = sgl_next_dma;
 	}
-	dma_pool_free(info->hw_sgl_pool, hw_sgl, psec_sgl);
 }
 
 static int sec_alg_skcipher_setkey(struct crypto_skcipher *tfm,