bpf: add improved helper for program-internal tail-call #30001
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
julianwiedmann
added
sig/datapath
julianwiedmann
force-pushed
the
1.16-bpf-tail-calls
branch
from
b1ae8ca
to
c2df139
Compare
The naming of ep_tail_call() is very misleading - it *doesn't* call to an endpoint's policy tail-call (in POLICY_CALL_MAP), and it's also used by programs that are *not* associated with an endpoint (eg. bpf_xdp and bpf_overlay). Instead it's used for a tail-call in the program's internal tail-call map. So start off with introducing a new helper with improved naming. Then let this helper return DROP_MISSED_TAIL_CALL (instead of every caller open-coding the same value), and also setting the index of the missed tail-call in `ext_err` where available. Finally steal a bit of compiler magic from the kernel, and enforce that callers check for returned errors. We've had too many cases in the past where we forgot to return the DROP_MISSED_TAIL_CALL. Then convert a few initial callers to demonstrate the usage. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
julianwiedmann
force-pushed
the
1.16-bpf-tail-calls
branch
from
c2df139
to
8982060
Compare
borkmann
approved these changes
Dec 20, 2023
qmonnet
approved these changes
Dec 20, 2023
|
/test |
|
Will follow-up with converting the other callers, and applying the same pattern to the policy map tail-calls. |
The story continues in #30288. |
7 tasks
julianwiedmann
added
the
backport-pending/1.15
github-actions
bot
added
backport-done/1.15
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The naming of ep_tail_call() is very misleading - it doesn't call to an endpoint's policy tail-call (in POLICY_CALL_MAP), and it's also used by programs that are not associated with an endpoint (eg. bpf_xdp and bpf_overlay). Instead it's used for a tail-call in the program's internal tail-call map.
So start off with introducing a new helper with improved naming. Then let this helper return DROP_MISSED_TAIL_CALL (instead of every caller open-coding the same value), and also setting the index of the missed tail-call in
ext_errwhere available.Finally steal a bit of compiler magic from the kernel, and enforce that callers check for returned errors. We've had too many cases in the past where we forgot to return the DROP_MISSED_TAIL_CALL.
Then convert a few initial callers to demonstrate the usage.