s390/qeth: consolidate skb allocation

Move the allocation of SG skbs into the main path. This allows for
a little code sharing, and handling ENOMEM from within one place.

As side effect, L2 SG skbs now get the proper amount of additional
headroom (read: zero) instead of the hard-coded ETH_HLEN.

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

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 1cf4e066955f64e5de79cf6d8c8a1daf7cc094aa..23b439fb5f2c134e026441cd5388b0c76b992fca 100644 (file)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5170,41 +5170,27 @@ out:
 }
 EXPORT_SYMBOL_GPL(qeth_core_hardsetup_card);
 
-static int qeth_create_skb_frag(struct qeth_qdio_buffer *qethbuffer,
-                               struct qdio_buffer_element *element,
-                               struct sk_buff **pskb, int offset, int data_len)
+static void qeth_create_skb_frag(struct qdio_buffer_element *element,
+                                struct sk_buff *skb, int offset, int data_len)
 {
        struct page *page = virt_to_page(element->addr);
        unsigned int next_frag;
 
-       if (*pskb == NULL) {
-               if (qethbuffer->rx_skb) {
-                       /* only if qeth_card.options.cq == QETH_CQ_ENABLED */
-                       *pskb = qethbuffer->rx_skb;
-                       qethbuffer->rx_skb = NULL;
-               } else {
-                       *pskb = dev_alloc_skb(QETH_RX_PULL_LEN + ETH_HLEN);
-                       if (!(*pskb))
-                               return -ENOMEM;
-               }
+       /* first fill the linear space */
+       if (!skb->len) {
+               unsigned int linear = min(data_len, skb_tailroom(skb));
 
-               skb_reserve(*pskb, ETH_HLEN);
-               if (data_len <= QETH_RX_PULL_LEN) {
-                       skb_put_data(*pskb, element->addr + offset, data_len);
-                       return 0;
-               } else {
-                       skb_put_data(*pskb, element->addr + offset,
-                                    QETH_RX_PULL_LEN);
-                       data_len -= QETH_RX_PULL_LEN;
-                       offset += QETH_RX_PULL_LEN;
-                       /* fall through to add page frag for remaining data */
-               }
+               skb_put_data(skb, element->addr + offset, linear);
+               data_len -= linear;
+               if (!data_len)
+                       return;
+               offset += linear;
+               /* fall through to add page frag for remaining data */
        }
 
-       next_frag = skb_shinfo(*pskb)->nr_frags;
+       next_frag = skb_shinfo(skb)->nr_frags;
        get_page(page);
-       skb_add_rx_frag(*pskb, next_frag, page, offset, data_len, data_len);
-       return 0;
+       skb_add_rx_frag(skb, next_frag, page, offset, data_len, data_len);
 }
 
 static inline int qeth_is_last_sbale(struct qdio_buffer_element *sbale)
@@ -5220,7 +5206,7 @@ struct sk_buff *qeth_core_get_next_skb(struct qeth_card *card,
        struct qdio_buffer_element *element = *__element;
        struct qdio_buffer *buffer = qethbuffer->buffer;
        int offset = *__offset;
-       struct sk_buff *skb = NULL;
+       struct sk_buff *skb;
        int skb_len = 0;
        void *data_ptr;
        int data_len;
@@ -5261,27 +5247,32 @@ struct sk_buff *qeth_core_get_next_skb(struct qeth_card *card,
        if (((skb_len >= card->options.rx_sg_cb) &&
             (!(card->info.type == QETH_CARD_TYPE_OSN)) &&
             (!atomic_read(&card->force_alloc_skb))) ||
-           (card->options.cq == QETH_CQ_ENABLED)) {
+           (card->options.cq == QETH_CQ_ENABLED))
                use_rx_sg = 1;
+
+       if (use_rx_sg && qethbuffer->rx_skb) {
+               /* QETH_CQ_ENABLED only: */
+               skb = qethbuffer->rx_skb;
+               qethbuffer->rx_skb = NULL;
        } else {
-               skb = dev_alloc_skb(skb_len + headroom);
-               if (!skb)
-                       goto no_mem;
-               if (headroom)
-                       skb_reserve(skb, headroom);
+               unsigned int linear = (use_rx_sg) ? QETH_RX_PULL_LEN : skb_len;
+
+               skb = dev_alloc_skb(linear + headroom);
        }
+       if (!skb)
+               goto no_mem;
+       if (headroom)
+               skb_reserve(skb, headroom);
 
        data_ptr = element->addr + offset;
        while (skb_len) {
                data_len = min(skb_len, (int)(element->length - offset));
                if (data_len) {
-                       if (use_rx_sg) {
-                               if (qeth_create_skb_frag(qethbuffer, element,
-                                   &skb, offset, data_len))
-                                       goto no_mem;
-                       } else {
+                       if (use_rx_sg)
+                               qeth_create_skb_frag(element, skb, offset,
+                                                    data_len);
+                       else
                                skb_put_data(skb, data_ptr, data_len);
-                       }
                }
                skb_len -= data_len;
                if (skb_len) {