sfc: Replace some literal constants with EFX_PAGE_SIZE/EFX_BUF_SIZE

The 'page size' for PCIe DMA, i.e. the alignment of boundaries at
which DMA must be broken, is 4KB.  Name this value as EFX_PAGE_SIZE
and use it in efx_max_tx_len().  Redefine EFX_BUF_SIZE as
EFX_PAGE_SIZE since its value is also a result of that requirement,
and use it in efx_init_special_buffer().

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 5cb81fa3fcbd..a096e287e95f 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -110,7 +110,7 @@ efx_max_tx_len(struct efx_nic *efx, dma_addr_t dma_addr)
          * little benefit from using descriptors that cross those
          * boundaries and we keep things simple by not doing so.
          */
-        unsigned len = (~dma_addr & 0xfff) + 1;
+        unsigned len = (~dma_addr & (EFX_PAGE_SIZE - 1)) + 1;
 
         /* Work around hardware bug for unaligned buffers. */
         if (EFX_WORKAROUND_5391(efx) && (dma_addr & 0xf))