diff options
| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2020-01-08 16:59:02 -0500 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2020-12-31 19:40:41 +0200 |
| commit | 1788f6e6adf6b5ffb3899c3353e31478e88bfde5 (patch) | |
| tree | 6353088fb12d8f1139fb69aacbe4729ffaf2bc2e /include/linux/skbuff.h | |
| parent | 0ed456705198d13d03b37d1206e4f1fd17256f2d (diff) | |
UPSTREAM: 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>
(cherry picked from commit dcfea72e79b0aa7a057c8f6024169d86a1bbc84b)
Bug: 152722841
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia8fe1237424161e4de23df4515dbb2275e15e180
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 95feb153fe9a..ab6a4fb9d82b 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1122,6 +1122,11 @@ static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb) return &skb_shinfo(skb)->hwtstamps; } +/* 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) + /** * skb_queue_empty - check if a queue is empty * @list: queue head |