diff options
| author | Willem de Bruijn <willemb@google.com> | 2023-02-14 10:57:40 -0500 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-02-15 21:26:36 -0800 |
| commit | 14ade6ba4120fb38fcb5033998882c5b3d591194 (patch) | |
| tree | a1e1c6ca6657492cad217a349b73a10556bef625 | |
| parent | c24a34f5a3d7dec595635ad54167a8c471e4e24f (diff) | |
net: msg_zerocopy: elide page accounting if RLIM_INFINITY
MSG_ZEROCOPY ensures that pinned user pages do not exceed the limit.
If no limit is set, skip this accounting as otherwise expensive
atomic_long operations are called for no reason.
This accounting is already skipped for privileged (CAP_IPC_LOCK)
users. Rely on the same mechanism: if no mmp->user is set,
mm_unaccount_pinned_pages does not decrement either.
Tested by running tools/testing/selftests/net/msg_zerocopy.sh with
an unprivileged user for the TXMODE binary:
ip netns exec "${NS1}" sudo -u "{$USER}" "${BIN}" "-${IP}" ...
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230214155740.3448763-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/skbuff.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 13ea10cf8544..98ebce9f6a51 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1406,14 +1406,18 @@ EXPORT_SYMBOL_GPL(skb_morph); int mm_account_pinned_pages(struct mmpin *mmp, size_t size) { - unsigned long max_pg, num_pg, new_pg, old_pg; + unsigned long max_pg, num_pg, new_pg, old_pg, rlim; struct user_struct *user; if (capable(CAP_IPC_LOCK) || !size) return 0; + rlim = rlimit(RLIMIT_MEMLOCK); + if (rlim == RLIM_INFINITY) + return 0; + num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */ - max_pg = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + max_pg = rlim >> PAGE_SHIFT; user = mmp->user ? : current_user(); old_pg = atomic_long_read(&user->locked_vm); |