3 files changed, 165 insertions, 32 deletions

diff --git a/drivers/s390/net/qeth.h b/drivers/s390/net/qeth.h
index b34eb82edd98..ec18bae05df0 100644
--- a/drivers/s390/net/qeth.h
+++ b/drivers/s390/net/qeth.h
@@ -211,6 +211,10 @@ struct qeth_perf_stats {
         /* initial values when measuring starts */
         unsigned long initial_rx_packets;
         unsigned long initial_tx_packets;
+        /* inbound scatter gather data */
+        unsigned int sg_skbs_rx;
+        unsigned int sg_frags_rx;
+        unsigned int sg_alloc_page_rx;
 };
 
 /* Routing stuff */
@@ -341,6 +345,9 @@ qeth_is_ipa_enabled(struct qeth_ipa_info *ipa, enum qeth_ipa_funcs func)
 
 #define QETH_IP_HEADER_SIZE 40
 
+/* large receive scatter gather copy break */
+#define QETH_RX_SG_CB (PAGE_SIZE >> 1)
+
 struct qeth_hdr_layer3 {
         __u8  id;
         __u8  flags;
@@ -771,6 +778,7 @@ struct qeth_card_options {
         int layer2;
         enum qeth_large_send_types large_send;
         int performance_stats;
+        int rx_sg_cb;
 };
 
 /*
@@ -828,6 +836,7 @@ struct qeth_card {
         int (*orig_hard_header)(struct sk_buff *,struct net_device *,
                                 unsigned short,void *,void *,unsigned);
         struct qeth_osn_info osn_info;
+        atomic_t force_alloc_skb;
 };
 
 struct qeth_card_list_struct {
diff --git a/drivers/s390/net/qeth_main.c b/drivers/s390/net/qeth_main.c
index 86b0c44165c1..8dca93598ea3 100644
--- a/drivers/s390/net/qeth_main.c
+++ b/drivers/s390/net/qeth_main.c
@@ -1054,6 +1054,7 @@ qeth_set_intial_options(struct qeth_card *card)
         else
                 card->options.layer2 = 0;
         card->options.performance_stats = 0;
+        card->options.rx_sg_cb = QETH_RX_SG_CB;
 }
 
 /**
@@ -2258,6 +2259,89 @@ qeth_get_skb(unsigned int length, struct qeth_hdr *hdr)
         return skb;
 }
 
+static inline int
+qeth_create_skb_frag(struct qdio_buffer_element *element,
+                     struct sk_buff **pskb,
+                     int offset, int *pfrag, int data_len)
+{
+        struct page *page = virt_to_page(element->addr);
+        if (*pfrag == 0) {
+                /* the upper protocol layers assume that there is data in the
+                 * skb itself. Copy a small amount (64 bytes) to make them
+                 * happy. */
+                *pskb = dev_alloc_skb(64 + QETH_FAKE_LL_LEN_ETH);
+                if (!(*pskb))
+                        return -ENOMEM;
+                skb_reserve(*pskb, QETH_FAKE_LL_LEN_ETH);
+                if (data_len <= 64) {
+                        memcpy(skb_put(*pskb, data_len), element->addr + offset,
+                                data_len);
+                } else {
+                        get_page(page);
+                        memcpy(skb_put(*pskb, 64), element->addr + offset, 64);
+                        skb_fill_page_desc(*pskb, *pfrag, page, offset + 64,
+                                data_len - 64);
+                        (*pskb)->data_len += data_len - 64;
+                        (*pskb)->len      += data_len - 64;
+                        (*pskb)->truesize += data_len - 64;
+                }
+        } else {
+                get_page(page);
+                skb_fill_page_desc(*pskb, *pfrag, page, offset, data_len);
+                (*pskb)->data_len += data_len;
+                (*pskb)->len      += data_len;
+                (*pskb)->truesize += data_len;
+        }
+        (*pfrag)++;
+        return 0;
+}
+
+static inline struct qeth_buffer_pool_entry *
+qeth_find_free_buffer_pool_entry(struct qeth_card *card)
+{
+        struct list_head *plh;
+        struct qeth_buffer_pool_entry *entry;
+        int i, free;
+        struct page *page;
+
+        if (list_empty(&card->qdio.in_buf_pool.entry_list))
+                return NULL;
+
+        list_for_each(plh, &card->qdio.in_buf_pool.entry_list) {
+                entry = list_entry(plh, struct qeth_buffer_pool_entry, list);
+                free = 1;
+                for (i = 0; i < QETH_MAX_BUFFER_ELEMENTS(card); ++i) {
+                        if (page_count(virt_to_page(entry->elements[i])) > 1) {
+                                free = 0;
+                                break;
+                        }
+                }
+                if (free) {
+                        list_del_init(&entry->list);
+                        return entry;
+                }
+        }
+
+        /* no free buffer in pool so take first one and swap pages */
+        entry = list_entry(card->qdio.in_buf_pool.entry_list.next,
+                        struct qeth_buffer_pool_entry, list);
+        for (i = 0; i < QETH_MAX_BUFFER_ELEMENTS(card); ++i) {
+                if (page_count(virt_to_page(entry->elements[i])) > 1) {
+                        page = alloc_page(GFP_ATOMIC|GFP_DMA);
+                        if (!page) {
+                                return NULL;
+                        } else {
+                                free_page((unsigned long)entry->elements[i]);
+                                entry->elements[i] = page_address(page);
+                                if (card->options.performance_stats)
+                                        card->perf_stats.sg_alloc_page_rx++;
+                        }
+                }
+        }
+        list_del_init(&entry->list);
+        return entry;
+}
+
 static struct sk_buff *
 qeth_get_next_skb(struct qeth_card *card, struct qdio_buffer *buffer,
                   struct qdio_buffer_element **__element, int *__offset,
@@ -2269,6 +2353,8 @@ qeth_get_next_skb(struct qeth_card *card, struct qdio_buffer *buffer,
         int skb_len;
         void *data_ptr;
         int data_len;
+        int use_rx_sg = 0;
+        int frag = 0;
 
         QETH_DBF_TEXT(trace,6,"nextskb");
         /* qeth_hdr must not cross element boundaries */
@@ -2293,23 +2379,43 @@ qeth_get_next_skb(struct qeth_card *card, struct qdio_buffer *buffer,
 
         if (!skb_len)
                 return NULL;
-        if (card->options.fake_ll){
-                if(card->dev->type == ARPHRD_IEEE802_TR){
-                        if (!(skb = qeth_get_skb(skb_len+QETH_FAKE_LL_LEN_TR, *hdr)))
-                                goto no_mem;
-                        skb_reserve(skb,QETH_FAKE_LL_LEN_TR);
+        if ((skb_len >= card->options.rx_sg_cb) &&
+            (!(card->info.type == QETH_CARD_TYPE_OSN)) &&
+            (!atomic_read(&card->force_alloc_skb))) {
+                use_rx_sg = 1;
+        } else {
+                if (card->options.fake_ll) {
+                        if (card->dev->type == ARPHRD_IEEE802_TR) {
+                                if (!(skb = qeth_get_skb(skb_len +
+                                                QETH_FAKE_LL_LEN_TR, *hdr)))
+                                        goto no_mem;
+                                skb_reserve(skb, QETH_FAKE_LL_LEN_TR);
+                        } else {
+                                if (!(skb = qeth_get_skb(skb_len +
+                                                QETH_FAKE_LL_LEN_ETH, *hdr)))
+                                        goto no_mem;
+                                skb_reserve(skb, QETH_FAKE_LL_LEN_ETH);
+                        }
                 } else {
-                        if (!(skb = qeth_get_skb(skb_len+QETH_FAKE_LL_LEN_ETH, *hdr)))
+                        skb = qeth_get_skb(skb_len, *hdr);
+                        if (!skb)
                                 goto no_mem;
-                        skb_reserve(skb,QETH_FAKE_LL_LEN_ETH);
                 }
-        } else if (!(skb = qeth_get_skb(skb_len, *hdr)))
-                goto no_mem;
+        }
+
         data_ptr = element->addr + offset;
         while (skb_len) {
                 data_len = min(skb_len, (int)(element->length - offset));
-                if (data_len)
-                        memcpy(skb_put(skb, data_len), data_ptr, data_len);
+                if (data_len) {
+                        if (use_rx_sg) {
+                                if (qeth_create_skb_frag(element, &skb, offset,
+                                    &frag, data_len))
+                                        goto no_mem;
+                        } else {
+                                memcpy(skb_put(skb, data_len), data_ptr,
+                                        data_len);
+                        }
+                }
                 skb_len -= data_len;
                 if (skb_len){
                         if (qeth_is_last_sbale(element)){
@@ -2331,6 +2437,10 @@ qeth_get_next_skb(struct qeth_card *card, struct qdio_buffer *buffer,
         }
         *__element = element;
         *__offset = offset;
+        if (use_rx_sg && card->options.performance_stats) {
+                card->perf_stats.sg_skbs_rx++;
+                card->perf_stats.sg_frags_rx += skb_shinfo(skb)->nr_frags;
+        }
         return skb;
 no_mem:
         if (net_ratelimit()){
@@ -2608,28 +2718,15 @@ qeth_process_inbound_buffer(struct qeth_card *card,
         }
 }
 
-static struct qeth_buffer_pool_entry *
-qeth_get_buffer_pool_entry(struct qeth_card *card)
-{
-        struct qeth_buffer_pool_entry *entry;
-
-        QETH_DBF_TEXT(trace, 6, "gtbfplen");
-        if (!list_empty(&card->qdio.in_buf_pool.entry_list)) {
-                entry = list_entry(card->qdio.in_buf_pool.entry_list.next,
-                                struct qeth_buffer_pool_entry, list);
-                list_del_init(&entry->list);
-                return entry;
-        }
-        return NULL;
-}
-
-static void
+static int
 qeth_init_input_buffer(struct qeth_card *card, struct qeth_qdio_buffer *buf)
 {
         struct qeth_buffer_pool_entry *pool_entry;
         int i;
- 
-        pool_entry = qeth_get_buffer_pool_entry(card);
+
+        pool_entry = qeth_find_free_buffer_pool_entry(card);
+        if (!pool_entry)
+                return 1;
         /*
          * since the buffer is accessed only from the input_tasklet
          * there shouldn't be a need to synchronize; also, since we use
@@ -2648,6 +2745,7 @@ qeth_init_input_buffer(struct qeth_card *card, struct qeth_qdio_buffer *buf)
                         buf->buffer->element[i].flags = 0;
         }
         buf->state = QETH_QDIO_BUF_EMPTY;
+        return 0;
 }
 
 static void
@@ -2682,6 +2780,7 @@ qeth_queue_input_buffer(struct qeth_card *card, int index)
         int count;
         int i;
         int rc;
+        int newcount = 0;
 
         QETH_DBF_TEXT(trace,6,"queinbuf");
         count = (index < queue->next_buf_to_init)?
@@ -2692,9 +2791,27 @@ qeth_queue_input_buffer(struct qeth_card *card, int index)
         /* only requeue at a certain threshold to avoid SIGAs */
         if (count >= QETH_IN_BUF_REQUEUE_THRESHOLD(card)){
                 for (i = queue->next_buf_to_init;
-                     i < queue->next_buf_to_init + count; ++i)
-                        qeth_init_input_buffer(card,
-                                &queue->bufs[i % QDIO_MAX_BUFFERS_PER_Q]);
+                     i < queue->next_buf_to_init + count; ++i) {
+                        if (qeth_init_input_buffer(card,
+                                &queue->bufs[i % QDIO_MAX_BUFFERS_PER_Q])) {
+                                break;
+                        } else {
+                                newcount++;
+                        }
+                }
+
+                if (newcount < count) {
+                        /* we are in memory shortage so we switch back to
+                           traditional skb allocation and drop packages */
+                        if (atomic_cmpxchg(&card->force_alloc_skb, 0, 1))
+                                printk(KERN_WARNING
+                                        "qeth: switch to alloc skb\n");
+                        count = newcount;
+                } else {
+                        if (atomic_cmpxchg(&card->force_alloc_skb, 1, 0))
+                                printk(KERN_WARNING "qeth: switch to sg\n");
+                }
+
                 /*
                  * according to old code it should be avoided to requeue all
                  * 128 buffers in order to benefit from PCI avoidance.
@@ -6494,6 +6611,7 @@ qeth_hardsetup_card(struct qeth_card *card)
 
         QETH_DBF_TEXT(setup, 2, "hrdsetup");
 
+        atomic_set(&card->force_alloc_skb, 0);
 retry:
         if (retries < 3){
                 PRINT_WARN("Retrying to do IDX activates.\n");
diff --git a/drivers/s390/net/qeth_proc.c b/drivers/s390/net/qeth_proc.c
index 89d56c8ecdd2..f1ff165a5e05 100644
--- a/drivers/s390/net/qeth_proc.c
+++ b/drivers/s390/net/qeth_proc.c
@@ -212,6 +212,12 @@ qeth_perf_procfile_seq_show(struct seq_file *s, void *it)
                       "  Skb fragments sent in SG mode          : %u\n\n",
                       card->perf_stats.sg_skbs_sent,
                       card->perf_stats.sg_frags_sent);
+        seq_printf(s, "  Skbs received in SG mode               : %u\n"
+                      "  Skb fragments received in SG mode      : %u\n"
+                      "  Page allocations for rx SG mode        : %u\n\n",
+                      card->perf_stats.sg_skbs_rx,
+                      card->perf_stats.sg_frags_rx,
+                      card->perf_stats.sg_alloc_page_rx);
         seq_printf(s, "  large_send tx (in Kbytes)              : %u\n"
                       "  large_send count                       : %u\n\n",
                       card->perf_stats.large_send_bytes >> 10,