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authorMaciej Fijalkowski <maciej.fijalkowski@intel.com>2022-06-07 16:22:00 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2022-06-08 16:20:07 +0200
commitd678cbd2f867a564a3c5b276c454e873f43f02f8 (patch)
tree666cbbad51a25ede8390f703b7f4816d051f89f0
parent2cf7b7ffdae519b284f1406012b52e2282fa36bf (diff)
downloadlinux-d678cbd2f867a564a3c5b276c454e873f43f02f8.tar.bz2
xsk: Fix handling of invalid descriptors in XSK TX batching API
xdpxceiver run on a AF_XDP ZC enabled driver revealed a problem with XSK Tx batching API. There is a test that checks how invalid Tx descriptors are handled by AF_XDP. Each valid descriptor is followed by invalid one on Tx side whereas the Rx side expects only to receive a set of valid descriptors. In current xsk_tx_peek_release_desc_batch() function, the amount of available descriptors is hidden inside xskq_cons_peek_desc_batch(). This can be problematic in cases where invalid descriptors are present due to the fact that xskq_cons_peek_desc_batch() returns only a count of valid descriptors. This means that it is impossible to properly update XSK ring state when calling xskq_cons_release_n(). To address this issue, pull out the contents of xskq_cons_peek_desc_batch() so that callers (currently only xsk_tx_peek_release_desc_batch()) will always be able to update the state of ring properly, as total count of entries is now available and use this value as an argument in xskq_cons_release_n(). By doing so, xskq_cons_peek_desc_batch() can be dropped altogether. Fixes: 9349eb3a9d2a ("xsk: Introduce batched Tx descriptor interfaces") Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/bpf/20220607142200.576735-1-maciej.fijalkowski@intel.com
-rw-r--r--net/xdp/xsk.c5
-rw-r--r--net/xdp/xsk_queue.h8
2 files changed, 3 insertions, 10 deletions
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index e0a4526ab66b..19ac872a6624 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -373,7 +373,8 @@ u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, u32 max_entries)
goto out;
}
- nb_pkts = xskq_cons_peek_desc_batch(xs->tx, pool, max_entries);
+ max_entries = xskq_cons_nb_entries(xs->tx, max_entries);
+ nb_pkts = xskq_cons_read_desc_batch(xs->tx, pool, max_entries);
if (!nb_pkts) {
xs->tx->queue_empty_descs++;
goto out;
@@ -389,7 +390,7 @@ u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, u32 max_entries)
if (!nb_pkts)
goto out;
- xskq_cons_release_n(xs->tx, nb_pkts);
+ xskq_cons_release_n(xs->tx, max_entries);
__xskq_cons_release(xs->tx);
xs->sk.sk_write_space(&xs->sk);
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index a794410989cc..fb20bf7207cf 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -282,14 +282,6 @@ static inline bool xskq_cons_peek_desc(struct xsk_queue *q,
return xskq_cons_read_desc(q, desc, pool);
}
-static inline u32 xskq_cons_peek_desc_batch(struct xsk_queue *q, struct xsk_buff_pool *pool,
- u32 max)
-{
- u32 entries = xskq_cons_nb_entries(q, max);
-
- return xskq_cons_read_desc_batch(q, pool, entries);
-}
-
/* To improve performance in the xskq_cons_release functions, only update local state here.
* Reflect this to global state when we get new entries from the ring in
* xskq_cons_get_entries() and whenever Rx or Tx processing are completed in the NAPI loop.