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
--- a/drivers/net/ixgbe/ixgbe_fcoe.c
+++ b/drivers/net/ixgbe/ixgbe_fcoe.c
@@ -159,7 +159,7 @@
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 @@
/* 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 @@
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 @@
}
}
#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 @@
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;
}