[SCSI] cxgb3i: Outgoing pdus need to observe skb's MAX_SKB_FRAGS

Need to make sure the outgoing pdu can fit into a single skb.  When
calulating the max. outgoing pdu payload size, take into consideration
of
- data can be held in the skb's fragment list, assume 512 bytes per
  fragment, and
- data can be held in the headroom.

Signed-off-by: Karen Xie <kxie@chelsio.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/scsi/cxgb3i/cxgb3i_offload.h b/drivers/scsi/cxgb3i/cxgb3i_offload.h
index df1eae0ee4be..6344b9eb2589 100644
--- a/drivers/scsi/cxgb3i/cxgb3i_offload.h
+++ b/drivers/scsi/cxgb3i/cxgb3i_offload.h
@@ -225,6 +225,7 @@ struct sge_opaque_hdr {
 /* for TX: a skb must have a headroom of at least TX_HEADER_LEN bytes */
 #define TX_HEADER_LEN \
                 (sizeof(struct tx_data_wr) + sizeof(struct sge_opaque_hdr))
+#define SKB_TX_HEADROOM         SKB_MAX_HEAD(TX_HEADER_LEN)
 
 /*
  * get and set private ip for iscsi traffic