s390/qeth: use memory reserves in TX slow path

When falling back to an allocation from the HW header cache, check if
the skb is eligible for using memory reserves.
This only makes a difference if the cache is empty and needs to be
refilled.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core_main.c

@@ -3705,6 +3705,7 @@ static int qeth_add_hw_header(struct qeth_qdio_out_q *queue,
 			      unsigned int hdr_len, unsigned int proto_len,
 			      unsigned int *elements)
 {
+	gfp_t gfp = GFP_ATOMIC | (skb_pfmemalloc(skb) ? __GFP_MEMALLOC : 0);
 	const unsigned int contiguous = proto_len ? proto_len : 1;
 	const unsigned int max_elements = queue->max_elements;
 	unsigned int __elements;
@@ -3760,10 +3761,11 @@ static int qeth_add_hw_header(struct qeth_qdio_out_q *queue,
 		*hdr = skb_push(skb, hdr_len);
 		return hdr_len;
 	}
-	/* fall back */
+
+	/* Fall back to cache element with known-good alignment: */
 	if (hdr_len + proto_len > QETH_HDR_CACHE_OBJ_SIZE)
 		return -E2BIG;
-	*hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
+	*hdr = kmem_cache_alloc(qeth_core_header_cache, gfp);
 	if (!*hdr)
 		return -ENOMEM;
 	/* Copy protocol headers behind HW header: */

drivers/s390/net/qeth_l2_main.c

@@ -499,6 +499,7 @@ static void qeth_l2_rx_mode_work(struct work_struct *work)
 static int qeth_l2_xmit_osn(struct qeth_card *card, struct sk_buff *skb,
 			    struct qeth_qdio_out_q *queue)
 {
+	gfp_t gfp = GFP_ATOMIC | (skb_pfmemalloc(skb) ? __GFP_MEMALLOC : 0);
 	struct qeth_hdr *hdr = (struct qeth_hdr *)skb->data;
 	addr_t end = (addr_t)(skb->data + sizeof(*hdr));
 	addr_t start = (addr_t)skb->data;
@@ -511,7 +512,7 @@ static int qeth_l2_xmit_osn(struct qeth_card *card, struct sk_buff *skb,
 
 	if (qeth_get_elements_for_range(start, end) > 1) {
 		/* Misaligned HW header, move it to its own buffer element. */
-		hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
+		hdr = kmem_cache_alloc(qeth_core_header_cache, gfp);
 		if (!hdr)
 			return -ENOMEM;
 		hd_len = sizeof(*hdr);