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| author | Alexey Dobriyan <adobriyan@sw.ru> | 2008-04-18 15:43:32 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-04-18 15:43:32 -0700 |
| commit | d1643d24c61b725bef399cc1cf2944b4c9c23177 (patch) | |
| tree | ad629b19f6331058001ef46fe6a45dd53122b7d8 | |
| parent | 3c051235a7f115c34e675c9cf55820bd3435f860 (diff) | |
| download | linux-d1643d24c61b725bef399cc1cf2944b4c9c23177.tar.gz | |
[NET]: Fix and allocate less memory for ->priv'less netdevices
This patch effectively reverts commit d0498d9ae1a5cebac363e38907266d5cd2eedf89 aka "[NET]: Do not allocate unneeded memory for dev->priv alignment." It was found to be buggy because of final unconditional += NETDEV_ALIGN_CONST removal. For example, for sizeof(struct net_device) being 2048 bytes, "alloc_size" was also 2048 bytes, but allocator with debugging options turned on started giving out !32-byte aligned memory resulting in redzones overwrites. Patch does small optimization in ->priv'less case: bumping size to next 32-byte boundary was always done to ensure ->priv will also be aligned. But, no ->priv, no need to do that. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/dev.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index c16a07fde388..e1df1ab3e04a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3996,12 +3996,15 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name, BUG_ON(strlen(name) >= sizeof(dev->name)); - /* ensure 32-byte alignment of both the device and private area */ - alloc_size = (sizeof(*dev) + NETDEV_ALIGN_CONST + - (sizeof(struct net_device_subqueue) * (queue_count - 1))) & - ~NETDEV_ALIGN_CONST; - if (sizeof_priv) - alloc_size += sizeof_priv + NETDEV_ALIGN_CONST; + alloc_size = sizeof(struct net_device) + + sizeof(struct net_device_subqueue) * (queue_count - 1); + if (sizeof_priv) { + /* ensure 32-byte alignment of private area */ + alloc_size = (alloc_size + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST; + alloc_size += sizeof_priv; + } + /* ensure 32-byte alignment of whole construct */ + alloc_size += NETDEV_ALIGN_CONST; p = kzalloc(alloc_size, GFP_KERNEL); if (!p) { |