ixgbe: work around for DDP last buffer size

A HW limitation was recently discovered where the last buffer in a DDP offload
cannot be a full buffer size in length. Fix the issue with a work around by
adding another buffer with size = 1.

Signed-off-by: Amir Hanania <amir.hanania@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ixgbe/ixgbe_fcoe.c b/drivers/net/ixgbe/ixgbe_fcoe.c
index 8753980..c54a882 100644 (file)
--- a/drivers/net/ixgbe/ixgbe_fcoe.c
+++ b/drivers/net/ixgbe/ixgbe_fcoe.c
@@ -159,7 +159,7 @@ int ixgbe_fcoe_ddp_get(struct net_device *netdev, u16 xid,
        struct scatterlist *sg;
        unsigned int i, j, dmacount;
        unsigned int len;
-       static const unsigned int bufflen = 4096;
+       static const unsigned int bufflen = IXGBE_FCBUFF_MIN;
        unsigned int firstoff = 0;
        unsigned int lastsize;
        unsigned int thisoff = 0;
@@ -254,6 +254,24 @@ int ixgbe_fcoe_ddp_get(struct net_device *netdev, u16 xid,
        /* only the last buffer may have non-full bufflen */
        lastsize = thisoff + thislen;
 
+       /*
+        * lastsize can not be buffer len.
+        * If it is then adding another buffer with lastsize = 1.
+        */
+       if (lastsize == bufflen) {
+               if (j >= IXGBE_BUFFCNT_MAX) {
+                       e_err(drv, "xid=%x:%d,%d,%d:addr=%llx "
+                               "not enough user buffers. We need an extra "
+                               "buffer because lastsize is bufflen.\n",
+                               xid, i, j, dmacount, (u64)addr);
+                       goto out_noddp_free;
+               }
+
+               ddp->udl[j] = (u64)(fcoe->extra_ddp_buffer_dma);
+               j++;
+               lastsize = 1;
+       }
+
        fcbuff = (IXGBE_FCBUFF_4KB << IXGBE_FCBUFF_BUFFSIZE_SHIFT);
        fcbuff |= ((j & 0xff) << IXGBE_FCBUFF_BUFFCNT_SHIFT);
        fcbuff |= (firstoff << IXGBE_FCBUFF_OFFSET_SHIFT);
@@ -532,6 +550,24 @@ void ixgbe_configure_fcoe(struct ixgbe_adapter *adapter)
                        e_err(drv, "failed to allocated FCoE DDP pool\n");
 
                spin_lock_init(&fcoe->lock);
+
+               /* Extra buffer to be shared by all DDPs for HW work around */
+               fcoe->extra_ddp_buffer = kmalloc(IXGBE_FCBUFF_MIN, GFP_ATOMIC);
+               if (fcoe->extra_ddp_buffer == NULL) {
+                       e_err(drv, "failed to allocated extra DDP buffer\n");
+                       goto out_extra_ddp_buffer_alloc;
+               }
+
+               fcoe->extra_ddp_buffer_dma =
+                       dma_map_single(&adapter->pdev->dev,
+                                      fcoe->extra_ddp_buffer,
+                                      IXGBE_FCBUFF_MIN,
+                                      DMA_FROM_DEVICE);
+               if (dma_mapping_error(&adapter->pdev->dev,
+                                     fcoe->extra_ddp_buffer_dma)) {
+                       e_err(drv, "failed to map extra DDP buffer\n");
+                       goto out_extra_ddp_buffer_dma;
+               }
        }
 
        /* Enable L2 eth type filter for FCoE */
@@ -581,6 +617,14 @@ void ixgbe_configure_fcoe(struct ixgbe_adapter *adapter)
                }
        }
 #endif
+
+       return;
+
+out_extra_ddp_buffer_dma:
+       kfree(fcoe->extra_ddp_buffer);
+out_extra_ddp_buffer_alloc:
+       pci_pool_destroy(fcoe->pool);
+       fcoe->pool = NULL;
 }
 
 /**
@@ -600,6 +644,11 @@ void ixgbe_cleanup_fcoe(struct ixgbe_adapter *adapter)
        if (fcoe->pool) {
                for (i = 0; i < IXGBE_FCOE_DDP_MAX; i++)
                        ixgbe_fcoe_ddp_put(adapter->netdev, i);
+               dma_unmap_single(&adapter->pdev->dev,
+                                fcoe->extra_ddp_buffer_dma,
+                                IXGBE_FCBUFF_MIN,
+                                DMA_FROM_DEVICE);
+               kfree(fcoe->extra_ddp_buffer);
                pci_pool_destroy(fcoe->pool);
                fcoe->pool = NULL;
        }

diff --git a/drivers/net/ixgbe/ixgbe_fcoe.h b/drivers/net/ixgbe/ixgbe_fcoe.h
index 4bc2c55..65cc8fb 100644 (file)
--- a/drivers/net/ixgbe/ixgbe_fcoe.h
+++ b/drivers/net/ixgbe/ixgbe_fcoe.h
@@ -70,6 +70,8 @@ struct ixgbe_fcoe {
        spinlock_t lock;
        struct pci_pool *pool;
        struct ixgbe_fcoe_ddp ddp[IXGBE_FCOE_DDP_MAX];
+       unsigned char *extra_ddp_buffer;
+       dma_addr_t extra_ddp_buffer_dma;
 };
 
 #endif /* _IXGBE_FCOE_H */