diff options
author | Jason A. Donenfeld <Jason@zx2c4.com> | 2020-01-09 00:59:02 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2020-01-09 02:19:54 +0300 |
commit | dcfea72e79b0aa7a057c8f6024169d86a1bbc84b (patch) | |
tree | 1a5a60c417ec5c29e22441f82264b2630937aa12 /include/linux/skbuff.h | |
parent | 542d3065f2b1a60a0cfc259c9a36faa470761d78 (diff) | |
download | linux-dcfea72e79b0aa7a057c8f6024169d86a1bbc84b.tar.xz |
net: introduce skb_list_walk_safe for skb segment walking
As part of the continual effort to remove direct usage of skb->next and
skb->prev, this patch adds a helper for iterating through the
singly-linked variant of skb lists, which are used for lists of GSO
packet. The name "skb_list_..." has been chosen to match the existing
function, "kfree_skb_list, which also operates on these singly-linked
lists, and the "..._walk_safe" part is the same idiom as elsewhere in
the kernel.
This patch removes the helper from wireguard and puts it into
linux/skbuff.h, while making it a bit more robust for general usage. In
particular, parenthesis are added around the macro argument usage, and it
now accounts for trying to iterate through an already-null skb pointer,
which will simply run the iteration zero times. This latter enhancement
means it can be used to replace both do { ... } while and while (...)
open-coded idioms.
This should take care of these three possible usages, which match all
current methods of iterations.
skb_list_walk_safe(segs, skb, next) { ... }
skb_list_walk_safe(skb, skb, next) { ... }
skb_list_walk_safe(segs, skb, segs) { ... }
Gcc appears to generate efficient code for each of these.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r-- | include/linux/skbuff.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index e9133bcf0544..64e5b1be9ff5 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1478,6 +1478,11 @@ static inline void skb_mark_not_on_list(struct sk_buff *skb) skb->next = NULL; } +/* Iterate through singly-linked GSO fragments of an skb. */ +#define skb_list_walk_safe(first, skb, next) \ + for ((skb) = (first), (next) = (skb) ? (skb)->next : NULL; (skb); \ + (skb) = (next), (next) = (skb) ? (skb)->next : NULL) + static inline void skb_list_del_init(struct sk_buff *skb) { __list_del_entry(&skb->list); |