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authorarybchik <arybchik@FreeBSD.org>2015-05-21 09:21:05 +0000
committerarybchik <arybchik@FreeBSD.org>2015-05-21 09:21:05 +0000
commit446dd8d19427cbc7fbe01ffd749b75171f08c5f8 (patch)
tree4313e47debe14ce7bb631981c26d3a5d297bf486
parentdb9589182b524f024f29cb27de0a6a2c5ed228e1 (diff)
downloadFreeBSD-src-446dd8d19427cbc7fbe01ffd749b75171f08c5f8.zip
FreeBSD-src-446dd8d19427cbc7fbe01ffd749b75171f08c5f8.tar.gz
MFC: r283048
sfxge: fix overflow queue freeze If TxQ lock is obtained, deferred packet list shold be serviced even if the packet addition fails because of overflow. Without the patch freeze happens if: - queue is not blocked (i.e. completion does not trigger unblock and service) - put-list overflow (1024 entries) - sfxge_tx_packet_add() acquires TxQ lock just as it is released it in sfxge_tx_qdpl_service() on the second CPU but before pending check - sfxge_tx_packet_add() swizzles put-list to get-list, fails because of non-tcp get-list overflow and returns without packet list service - sfxge_tx_qdpl_service() on the second CPU checks that there are no pending packets in the put-list and returns Other possible solution is to guaranee that maximum length of the put-list is less than maximum length of any get-list. Sponsored by: Solarflare Communications, Inc.
-rw-r--r--sys/dev/sfxge/sfxge_tx.c10
1 files changed, 2 insertions, 8 deletions
diff --git a/sys/dev/sfxge/sfxge_tx.c b/sys/dev/sfxge/sfxge_tx.c
index 466cefd..18c86427 100644
--- a/sys/dev/sfxge/sfxge_tx.c
+++ b/sys/dev/sfxge/sfxge_tx.c
@@ -619,18 +619,12 @@ sfxge_tx_packet_add(struct sfxge_txq *txq, struct mbuf *m)
sfxge_tx_qdpl_swizzle(txq);
rc = sfxge_tx_qdpl_put_locked(txq, m);
- if (rc != 0) {
- SFXGE_TXQ_UNLOCK(txq);
- return (rc);
- }
/* Try to service the list. */
sfxge_tx_qdpl_service(txq);
/* Lock has been dropped. */
} else {
rc = sfxge_tx_qdpl_put_unlocked(txq, m);
- if (rc != 0)
- return (rc);
/*
* Try to grab the lock again.
@@ -639,7 +633,7 @@ sfxge_tx_packet_add(struct sfxge_txq *txq, struct mbuf *m)
* the deferred packet list. If we are not able to get
* the lock, another thread is processing the list.
*/
- if (SFXGE_TXQ_TRYLOCK(txq)) {
+ if ((rc == 0) && SFXGE_TXQ_TRYLOCK(txq)) {
sfxge_tx_qdpl_service(txq);
/* Lock has been dropped. */
}
@@ -647,7 +641,7 @@ sfxge_tx_packet_add(struct sfxge_txq *txq, struct mbuf *m)
SFXGE_TXQ_LOCK_ASSERT_NOTOWNED(txq);
- return (0);
+ return (rc);
}
static void
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