user/sven/linux.git/include/linux/skbuff_ref.h, branch v6.10.7Linux Kernel
https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v6.10.72024-05-03T23:05:53ZRevert "net: mirror skb frag ref/unref helpers"2024-05-03T23:05:53ZMina Almasryalmasrymina@google.com2024-05-02T17:54:22Zurn:sha1:173e7622ccb3f46834bd4176ed363f435e142942
This reverts commit a580ea994fd37f4105028f5a85c38ff6508a2b25.
This revert is to resolve Dragos's report of page_pool leak here:
https://lore.kernel.org/lkml/20240424165646.1625690-2-dtatulea@nvidia.com/
The reverted patch interacts very badly with commit 2cc3aeb5eccc ("skbuff:
Fix a potential race while recycling page_pool packets"). The reverted
commit hopes that the pp_recycle + is_pp_page variables do not change
between the skb_frag_ref and skb_frag_unref operation. If such a change
occurs, the skb_frag_ref/unref will not operate on the same reference type.
In the case of Dragos's report, the grabbed ref was a pp ref, but the unref
was a page ref, because the pp_recycle setting on the skb was changed.
Attempting to fix this issue on the fly is risky. Lets revert and I hope
to reland this with better understanding and testing to ensure we don't
regress some edge case while streamlining skb reffing.
Fixes: a580ea994fd3 ("net: mirror skb frag ref/unref helpers")
Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Mina Almasry <almasrymina@google.com>
Link: https://lore.kernel.org/r/20240502175423.2456544-1-almasrymina@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: mirror skb frag ref/unref helpers2024-04-12T02:29:23ZMina Almasryalmasrymina@google.com2024-04-10T19:05:02Zurn:sha1:a580ea994fd37f4105028f5a85c38ff6508a2b25
Refactor some of the skb frag ref/unref helpers for improved clarity.
Implement napi_pp_get_page() to be the mirror counterpart of
napi_pp_put_page().
Implement skb_page_ref() to be the mirror of skb_page_unref().
Improve __skb_frag_ref() to become a mirror counterpart of
__skb_frag_unref(). Previously unref could handle pp & non-pp pages,
while the ref could only handle non-pp pages. Now both the ref & unref
helpers can correctly handle both pp & non-pp pages.
Now that __skb_frag_ref() can handle both pp & non-pp pages, remove
skb_pp_frag_ref(), and use __skb_frag_ref() instead. This lets us
remove pp specific handling from skb_try_coalesce.
Additionally, since __skb_frag_ref() can now handle both pp & non-pp
pages, a latent issue in skb_shift() should now be fixed. Previously
this function would do a non-pp ref & pp unref on potential pp frags
(fragfrom). After this patch, skb_shift() should correctly do a pp
ref/unref on pp frags.
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20240410190505.1225848-3-almasrymina@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: move skb ref helpers to new header2024-04-12T02:29:22ZMina Almasryalmasrymina@google.com2024-04-10T19:05:01Zurn:sha1:f6d827b180bda01f8805bf5e85307419b0d6f890
Add a new header, linux/skbuff_ref.h, which contains all the skb_*_ref()
helpers. Many of the consumers of skbuff.h do not actually use any of
the skb ref helpers, and we can speed up compilation a bit by minimizing
this header file.
Additionally in the later patch in the series we add page_pool support
to skb_frag_ref(), which requires some page_pool dependencies. We can
now add these dependencies to skbuff_ref.h instead of a very ubiquitous
skbuff.h
Signed-off-by: Mina Almasry <almasrymina@google.com>
Link: https://lore.kernel.org/r/20240410190505.1225848-2-almasrymina@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>