Commit 67ae7cf1 authored Jul 21, 2011 by Ben Hutchings Committed by David S. Miller Jul 21, 2011

ethtool: Allow zero-length register dumps again



Some drivers (ab)use the ethtool_ops::get_regs operation to expose
only a hardware revision ID.  Commit
a77f5db3 ('ethtool: Allocate register
dump buffer with vmalloc()') had the side-effect of breaking these, as
vmalloc() returns a null pointer for size=0 whereas kmalloc() did not.

For backward-compatibility, allow zero-length dumps again.

Reported-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Cc: stable@kernel.org [2.6.37+]
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1511022c

net/core/ethtool.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -923,7 +923,7 @@ static int ethtool_get_regs(struct net_device dev, char __user useraddr)
		regs.len = reglen;

		regbuf = vzalloc(reglen);
		if (!regbuf)
		if (reglen && !regbuf)
		return -ENOMEM;

		ops->get_regs(dev, &regs, regbuf);
		@@ -932,7 +932,7 @@ static int ethtool_get_regs(struct net_device dev, char __user useraddr)
		if (copy_to_user(useraddr, &regs, sizeof(regs)))
		goto out;
		useraddr += offsetof(struct ethtool_regs, data);
		if (copy_to_user(useraddr, regbuf, regs.len))
		if (regbuf && copy_to_user(useraddr, regbuf, regs.len))
		goto out;
		ret = 0;

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