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	1. Check for -EPROBE_DEFER
If it occurs we have to return immediately. Trying other properties
could result in another error and ignoring -EPROBE_DEFER which has a
special meaning.
2. Check for read result
Assuming property->read() success can result in NULL pointer
dereference. It happens e.g. for "mac-address" with NVMEM cell
containing invalid MAC.
3. Simplify code
Don't move cell reading & nvmem_cell_put() into a loop. Simplify loop
code.
Fixes: ecd81de7a5 ("ath79: add nvmem cell mac-address-ascii support")
Cc: Yousong Zhou <yszhou4tech@gmail.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
		
	
			
		
			
				
	
	
		
			112 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			112 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From: Yousong Zhou <yszhou4tech@gmail.com>
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Subject: [PATCH] ath79: add nvmem cell mac-address-ascii support
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This is needed for devices with mac address stored in ascii format, e.g.
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HiWiFi HC6361 to be ported in the following patch.
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Submitted-by: Yousong Zhou <yszhou4tech@gmail.com>
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---
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 net/ethernet/eth.c                            | 83 ++++++++++++------
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 1 files changed, 72 insertions(+), 11 deletions(-)
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--- a/net/ethernet/eth.c
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+++ b/net/ethernet/eth.c
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@@ -538,6 +538,63 @@ int eth_platform_get_mac_address(struct
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 }
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 EXPORT_SYMBOL(eth_platform_get_mac_address);
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+static void *nvmem_cell_get_mac_address(struct nvmem_cell *cell)
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+{
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+	size_t len;
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+	void *mac;
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+
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+	mac = nvmem_cell_read(cell, &len);
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+	if (IS_ERR(mac))
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+		return mac;
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+	if (len != ETH_ALEN) {
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+		kfree(mac);
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+		return ERR_PTR(-EINVAL);
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+	}
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+	return mac;
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+}
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+
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+static void *nvmem_cell_get_mac_address_ascii(struct nvmem_cell *cell)
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+{
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+	size_t len;
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+	int ret;
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+	void *mac_ascii;
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+	u8 *mac;
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+
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+	mac_ascii = nvmem_cell_read(cell, &len);
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+	if (IS_ERR(mac_ascii))
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+		return mac_ascii;
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+	if (len != ETH_ALEN*2+5) {
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+		kfree(mac_ascii);
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+		return ERR_PTR(-EINVAL);
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+	}
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+	mac = kmalloc(ETH_ALEN, GFP_KERNEL);
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+	if (!mac) {
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+		kfree(mac_ascii);
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+		return ERR_PTR(-ENOMEM);
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+	}
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+	ret = sscanf(mac_ascii, "%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx",
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+				&mac[0], &mac[1], &mac[2],
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+				&mac[3], &mac[4], &mac[5]);
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+	kfree(mac_ascii);
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+	if (ret == ETH_ALEN)
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+		return mac;
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+	kfree(mac);
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+	return ERR_PTR(-EINVAL);
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+}
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+
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+static struct nvmem_cell_mac_address_property {
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+	char *name;
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+	void *(*read)(struct nvmem_cell *);
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+} nvmem_cell_mac_address_properties[] = {
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+	{
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+		.name = "mac-address",
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+		.read = nvmem_cell_get_mac_address,
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+	}, {
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+		.name = "mac-address-ascii",
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+		.read = nvmem_cell_get_mac_address_ascii,
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+	},
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+};
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+
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 /**
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  * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
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  * 'mac-address' associated with given device.
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@@ -549,21 +606,28 @@ EXPORT_SYMBOL(eth_platform_get_mac_addre
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  */
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 int nvmem_get_mac_address(struct device *dev, void *addrbuf)
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 {
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+	struct nvmem_cell_mac_address_property *property;
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 	struct nvmem_cell *cell;
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 	const void *mac;
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-	size_t len;
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+	int i;
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+
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+	for (i = 0; i < ARRAY_SIZE(nvmem_cell_mac_address_properties); i++) {
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+		property = &nvmem_cell_mac_address_properties[i];
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+		cell = nvmem_cell_get(dev, property->name);
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+		/* For -EPROBE_DEFER don't try other properties. We'll get back to this one. */
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+		if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
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+			break;
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+	}
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-	cell = nvmem_cell_get(dev, "mac-address");
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 	if (IS_ERR(cell))
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 		return PTR_ERR(cell);
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-	mac = nvmem_cell_read(cell, &len);
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+	mac = property->read(cell);
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 	nvmem_cell_put(cell);
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-
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 	if (IS_ERR(mac))
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 		return PTR_ERR(mac);
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-	if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
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+	if (!is_valid_ether_addr(mac)) {
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 		kfree(mac);
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 		return -EINVAL;
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 	}
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