[ETHTOOL]: Add support for large eeproms

Currently, it is not possible to read/write to an eeprom larger than
128k in size because the buffer used for temporarily storing the
eeprom contents is allocated using kmalloc. kmalloc can only allocate
a maximum of 128k depending on architecture.

Modified ethtool_get/set_eeprom to only allocate a page of memory and
then copy the eeprom a page at a time.

Updated original patch as per suggestions from Joe Perches.

Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 36 insertions, 28 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 1163eb2256d0..a29b43d0b450 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -284,8 +284,10 @@ static int ethtool_get_eeprom(struct net_device *dev, void __user *useraddr)
 {
         struct ethtool_eeprom eeprom;
         const struct ethtool_ops *ops = dev->ethtool_ops;
+        void __user *userbuf = useraddr + sizeof(eeprom);
+        u32 bytes_remaining;
         u8 *data;
-        int ret;
+        int ret = 0;
 
         if (!ops->get_eeprom || !ops->get_eeprom_len)
                 return -EOPNOTSUPP;
@@ -301,26 +303,26 @@ static int ethtool_get_eeprom(struct net_device *dev, void __user *useraddr)
         if (eeprom.offset + eeprom.len > ops->get_eeprom_len(dev))
                 return -EINVAL;
 
-        data = kmalloc(eeprom.len, GFP_USER);
+        data = kmalloc(PAGE_SIZE, GFP_USER);
         if (!data)
                 return -ENOMEM;
 
-        ret = -EFAULT;
-        if (copy_from_user(data, useraddr + sizeof(eeprom), eeprom.len))
-                goto out;
-
-        ret = ops->get_eeprom(dev, &eeprom, data);
-        if (ret)
-                goto out;
+        bytes_remaining = eeprom.len;
+        while (bytes_remaining > 0) {
+                eeprom.len = min(bytes_remaining, (u32)PAGE_SIZE);
 
-        ret = -EFAULT;
-        if (copy_to_user(useraddr, &eeprom, sizeof(eeprom)))
-                goto out;
-        if (copy_to_user(useraddr + sizeof(eeprom), data, eeprom.len))
-                goto out;
-        ret = 0;
+                ret = ops->get_eeprom(dev, &eeprom, data);
+                if (ret)
+                        break;
+                if (copy_to_user(userbuf, data, eeprom.len)) {
+                        ret = -EFAULT;
+                        break;
+                }
+                userbuf += eeprom.len;
+                eeprom.offset += eeprom.len;
+                bytes_remaining -= eeprom.len;
+        }
 
- out:
         kfree(data);
         return ret;
 }
@@ -329,8 +331,10 @@ static int ethtool_set_eeprom(struct net_device *dev, void __user *useraddr)
 {
         struct ethtool_eeprom eeprom;
         const struct ethtool_ops *ops = dev->ethtool_ops;
+        void __user *userbuf = useraddr + sizeof(eeprom);
+        u32 bytes_remaining;
         u8 *data;
-        int ret;
+        int ret = 0;
 
         if (!ops->set_eeprom || !ops->get_eeprom_len)
                 return -EOPNOTSUPP;
@@ -346,22 +350,26 @@ static int ethtool_set_eeprom(struct net_device *dev, void __user *useraddr)
         if (eeprom.offset + eeprom.len > ops->get_eeprom_len(dev))
                 return -EINVAL;
 
-        data = kmalloc(eeprom.len, GFP_USER);
+        data = kmalloc(PAGE_SIZE, GFP_USER);
         if (!data)
                 return -ENOMEM;
 
-        ret = -EFAULT;
-        if (copy_from_user(data, useraddr + sizeof(eeprom), eeprom.len))
-                goto out;
-
-        ret = ops->set_eeprom(dev, &eeprom, data);
-        if (ret)
-                goto out;
+        bytes_remaining = eeprom.len;
+        while (bytes_remaining > 0) {
+                eeprom.len = min(bytes_remaining, (u32)PAGE_SIZE);
 
-        if (copy_to_user(useraddr + sizeof(eeprom), data, eeprom.len))
-                ret = -EFAULT;
+                if (copy_from_user(data, userbuf, eeprom.len)) {
+                        ret = -EFAULT;
+                        break;
+                }
+                ret = ops->set_eeprom(dev, &eeprom, data);
+                if (ret)
+                        break;
+                userbuf += eeprom.len;
+                eeprom.offset += eeprom.len;
+                bytes_remaining -= eeprom.len;
+        }
 
- out:
         kfree(data);
         return ret;
 }