ethtool: Allocate register dump buffer with vmalloc()

Some NICs have huge register files which exceed the maximum heap
allocation size.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/ethtool.c

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 91ffce2..dae2fd0 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -815,7 +815,7 @@
 	if (regs.len > reglen)
 		regs.len = reglen;
 
-	regbuf = kmalloc(reglen, GFP_USER);
+	regbuf = vmalloc(reglen);
 	if (!regbuf)
 		return -ENOMEM;
 
@@ -830,7 +830,7 @@
 	ret = 0;
 
  out:
-	kfree(regbuf);
+	vfree(regbuf);
 	return ret;
 }