qeth: refactor calculation of SBALE count
Rewrite the functions that calculate the required number of buffer
elements needed to represent SKB data, to make them hopefully more
comprehensible. Plus a few cleanups.
Signed-off-by: Eugene Crosser <Eugene.Crosser@ru.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index ac54433..7c9968a 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2793,15 +2793,34 @@
}
}
-static inline int qeth_l3_tso_elements(struct sk_buff *skb)
+/**
+ * qeth_get_elements_no_tso() - find number of SBALEs for skb data, inc. frags.
+ * @card: qeth card structure, to check max. elems.
+ * @skb: SKB address
+ * @extra_elems: extra elems needed, to check against max.
+ *
+ * Returns the number of pages, and thus QDIO buffer elements, needed to cover
+ * skb data, including linear part and fragments, but excluding TCP header.
+ * (Exclusion of TCP header distinguishes it from qeth_get_elements_no().)
+ * Checks if the result plus extra_elems fits under the limit for the card.
+ * Returns 0 if it does not.
+ * Note: extra_elems is not included in the returned result.
+ */
+static int qeth_get_elements_no_tso(struct qeth_card *card,
+ struct sk_buff *skb, int extra_elems)
{
- unsigned long tcpd = (unsigned long)tcp_hdr(skb) +
- tcp_hdr(skb)->doff * 4;
- int tcpd_len = skb_headlen(skb) - (tcpd - (unsigned long)skb->data);
- int elements = PFN_UP(tcpd + tcpd_len - 1) - PFN_DOWN(tcpd);
+ addr_t tcpdptr = (addr_t)tcp_hdr(skb) + tcp_hdrlen(skb);
+ int elements = qeth_get_elements_for_range(
+ tcpdptr,
+ (addr_t)skb->data + skb_headlen(skb)) +
+ qeth_get_elements_for_frags(skb);
- elements += qeth_get_elements_for_frags(skb);
-
+ if ((elements + extra_elems) > QETH_MAX_BUFFER_ELEMENTS(card)) {
+ QETH_DBF_MESSAGE(2,
+ "Invalid size of TSO IP packet (Number=%d / Length=%d). Discarded.\n",
+ elements + extra_elems, skb->len);
+ return 0;
+ }
return elements;
}
@@ -2810,8 +2829,8 @@
int rc;
u16 *tag;
struct qeth_hdr *hdr = NULL;
- int elements_needed = 0;
- int elems;
+ int hdr_elements = 0;
+ int elements;
struct qeth_card *card = dev->ml_priv;
struct sk_buff *new_skb = NULL;
int ipv = qeth_get_ip_version(skb);
@@ -2859,7 +2878,7 @@
hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
if (!hdr)
goto tx_drop;
- elements_needed++;
+ hdr_elements++;
} else {
/* create a clone with writeable headroom */
new_skb = skb_realloc_headroom(skb, sizeof(struct qeth_hdr_tso)
@@ -2895,7 +2914,7 @@
* chaining we can not send long frag lists
*/
if (large_send) {
- if (qeth_l3_tso_elements(new_skb) + 1 > 16) {
+ if (!qeth_get_elements_no_tso(card, new_skb, 1)) {
if (skb_linearize(new_skb))
goto tx_drop;
if (card->options.performance_stats)
@@ -2909,7 +2928,7 @@
memset(hdr, 0, sizeof(struct qeth_hdr_tso));
qeth_l3_fill_header(card, hdr, new_skb, ipv, cast_type);
qeth_tso_fill_header(card, hdr, new_skb);
- elements_needed++;
+ hdr_elements++;
} else {
if (data_offset < 0) {
hdr = (struct qeth_hdr *)skb_push(new_skb,
@@ -2930,31 +2949,29 @@
qeth_l3_hdr_csum(card, hdr, new_skb);
}
- elems = qeth_get_elements_no(card, new_skb, elements_needed);
- if (!elems) {
+ elements = qeth_get_elements_no(card, new_skb, hdr_elements);
+ if (!elements) {
if (data_offset >= 0)
kmem_cache_free(qeth_core_header_cache, hdr);
goto tx_drop;
}
- elements_needed += elems;
- nr_frags = skb_shinfo(new_skb)->nr_frags;
+ elements += hdr_elements;
if (card->info.type != QETH_CARD_TYPE_IQD) {
int len;
if (large_send)
len = ((unsigned long)tcp_hdr(new_skb) +
- tcp_hdr(new_skb)->doff * 4) -
+ tcp_hdrlen(new_skb)) -
(unsigned long)new_skb->data;
else
len = sizeof(struct qeth_hdr_layer3);
if (qeth_hdr_chk_and_bounce(new_skb, &hdr, len))
goto tx_drop;
- rc = qeth_do_send_packet(card, queue, new_skb, hdr,
- elements_needed);
+ rc = qeth_do_send_packet(card, queue, new_skb, hdr, elements);
} else
rc = qeth_do_send_packet_fast(card, queue, new_skb, hdr,
- elements_needed, data_offset, 0);
+ elements, data_offset, 0);
if (!rc) {
card->stats.tx_packets++;
@@ -2962,6 +2979,7 @@
if (new_skb != skb)
dev_kfree_skb_any(skb);
if (card->options.performance_stats) {
+ nr_frags = skb_shinfo(new_skb)->nr_frags;
if (large_send) {
card->perf_stats.large_send_bytes += tx_bytes;
card->perf_stats.large_send_cnt++;