mlx4_core: For 64-bit systems, vmap() kernel queue buffers
Since kernel virtual memory is not a problem on 64-bit systems, there
is no reason to use our own 2-layer page mapping scheme for large
kernel queue buffers on such systems. Instead, map the page list to a
single virtually contiguous buffer with vmap(), so that can we access
buffer memory via direct indexing.
Signed-off-by: Michael S. Tsirkin <mst@dev.mellanox.co.il>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/net/mlx4/alloc.c b/drivers/net/mlx4/alloc.c
index b226e01..2da2c2e 100644
--- a/drivers/net/mlx4/alloc.c
+++ b/drivers/net/mlx4/alloc.c
@@ -151,6 +151,19 @@
memset(buf->u.page_list[i].buf, 0, PAGE_SIZE);
}
+
+ if (BITS_PER_LONG == 64) {
+ struct page **pages;
+ pages = kmalloc(sizeof *pages * buf->nbufs, GFP_KERNEL);
+ if (!pages)
+ goto err_free;
+ for (i = 0; i < buf->nbufs; ++i)
+ pages[i] = virt_to_page(buf->u.page_list[i].buf);
+ buf->u.direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
+ kfree(pages);
+ if (!buf->u.direct.buf)
+ goto err_free;
+ }
}
return 0;
@@ -170,6 +183,9 @@
dma_free_coherent(&dev->pdev->dev, size, buf->u.direct.buf,
buf->u.direct.map);
else {
+ if (BITS_PER_LONG == 64)
+ vunmap(buf->u.direct.buf);
+
for (i = 0; i < buf->nbufs; ++i)
if (buf->u.page_list[i].buf)
dma_free_coherent(&dev->pdev->dev, PAGE_SIZE,