So, I'm begining to look more closely at xen. Trying to get it all to
compile, and work with our hardware.
After overlaying the 2.6.8.1 sparse tree, I looked at the diff of the source.
In net/core/skbuff.c, I see a function alloc_skb_from_cache. This function
uses goto, when it's not needed.
+struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
+ unsigned int size, int gfp_mask)
+{
+ struct sk_buff *skb;
+ u8 *data;
+
+ /* Get the HEAD */
+ skb = kmem_cache_alloc(skbuff_head_cache,
+ gfp_mask & ~__GFP_DMA);
+ if (!skb)
+ goto out;
Replace the above 2 lines with:
if (!skb)
return NULL;
+
+ /* Get the DATA. */
+ size = SKB_DATA_ALIGN(size);
+ data = kmem_cache_alloc(cp, gfp_mask);
+ if (!data)
+ goto nodata;
Replace the above 2 lines with:
if (!data) {
kmem_cache_free(skbuff_head_cache, skb);
return NULL;
}
+
+ memset(skb, 0, offsetof(struct sk_buff, truesize));
+ skb->truesize = size + sizeof(struct sk_buff);
+ atomic_set(&skb->users, 1);
+ skb->head = data;
+ skb->data = data;
+ skb->tail = data;
+ skb->end = data + size;
+
+ atomic_set(&(skb_shinfo(skb)->dataref), 1);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb_shinfo(skb)->tso_size = 0;
+ skb_shinfo(skb)->tso_segs = 0;
+ skb_shinfo(skb)->frag_list = NULL;
+out:
Remove this line.
+ return skb;
+nodata:
+ kmem_cache_free(skbuff_head_cache, skb);
+ skb = NULL;
+ goto out;
Remove these 4 lines.
Also, why use atomic_set here? Wouldn't this newly allocated skb only have
one reference?
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