s390/qeth: remove qeth_hdr_chk_and_bounce()

Restructure the OSN xmit path to handle misaligned HW headers properly,
without shifting the packet data around.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 28 insertions, 31 deletions

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 1c9fce609eb9..be213b5c2552 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -1021,7 +1021,6 @@ void qeth_dbf_longtext(debug_info_t *id, int level, char *text, ...);
 int qeth_core_ethtool_get_link_ksettings(struct net_device *netdev,
                                          struct ethtool_link_ksettings *cmd);
 int qeth_set_access_ctrl_online(struct qeth_card *card, int fallback);
-int qeth_hdr_chk_and_bounce(struct sk_buff *, struct qeth_hdr **, int);
 int qeth_configure_cq(struct qeth_card *, enum qeth_cq);
 int qeth_hw_trap(struct qeth_card *, enum qeth_diags_trap_action);
 void qeth_trace_features(struct qeth_card *);
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 7426167eace2..c7f7061a7205 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -3823,27 +3823,6 @@ unsigned int qeth_count_elements(struct sk_buff *skb, unsigned int data_offset)
 }
 EXPORT_SYMBOL_GPL(qeth_count_elements);
 
-int qeth_hdr_chk_and_bounce(struct sk_buff *skb, struct qeth_hdr **hdr, int len)
-{
-        int hroom, inpage, rest;
-
-        if (((unsigned long)skb->data & PAGE_MASK) !=
-            (((unsigned long)skb->data + len - 1) & PAGE_MASK)) {
-                hroom = skb_headroom(skb);
-                inpage = PAGE_SIZE - ((unsigned long) skb->data % PAGE_SIZE);
-                rest = len - inpage;
-                if (rest > hroom)
-                        return 1;
-                memmove(skb->data - rest, skb->data, skb_headlen(skb));
-                skb->data -= rest;
-                skb->tail -= rest;
-                *hdr = (struct qeth_hdr *)skb->data;
-                QETH_DBF_MESSAGE(2, "skb bounce len: %d rest: %d\n", len, rest);
-        }
-        return 0;
-}
-EXPORT_SYMBOL_GPL(qeth_hdr_chk_and_bounce);
-
 #define QETH_HDR_CACHE_OBJ_SIZE         (sizeof(struct qeth_hdr_tso) + \
                                          MAX_TCP_HEADER)
 
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 24b531ca2827..33b65471a68a 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -650,19 +650,38 @@ static void qeth_l2_set_rx_mode(struct net_device *dev)
 static int qeth_l2_xmit_osn(struct qeth_card *card, struct sk_buff *skb,
                             struct qeth_qdio_out_q *queue)
 {
-        unsigned int elements;
-        struct qeth_hdr *hdr;
+        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;
+        unsigned int elements = 0;
+        unsigned int hd_len = 0;
+        int rc;
 
         if (skb->protocol == htons(ETH_P_IPV6))
                 return -EPROTONOSUPPORT;
 
-        hdr = (struct qeth_hdr *)skb->data;
-        elements = qeth_count_elements(skb, 0);
-        if (elements > QETH_MAX_BUFFER_ELEMENTS(card))
-                return -E2BIG;
-        if (qeth_hdr_chk_and_bounce(skb, &hdr, sizeof(*hdr)))
-                return -EINVAL;
-        return qeth_do_send_packet(card, queue, skb, hdr, 0, 0, elements);
+        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);
+                if (!hdr)
+                        return -ENOMEM;
+                hd_len = sizeof(*hdr);
+                skb_copy_from_linear_data(skb, (char *)hdr, hd_len);
+                elements++;
+        }
+
+        elements += qeth_count_elements(skb, hd_len);
+        if (elements > QETH_MAX_BUFFER_ELEMENTS(card)) {
+                rc = -E2BIG;
+                goto out;
+        }
+
+        rc = qeth_do_send_packet(card, queue, skb, hdr, hd_len, hd_len,
+                                 elements);
+out:
+        if (rc && hd_len)
+                kmem_cache_free(qeth_core_header_cache, hdr);
+        return rc;
 }
 
 static netdev_tx_t qeth_l2_hard_start_xmit(struct sk_buff *skb,