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From: Julien Meunier <julien.meunier@nokia.com>
To: dev@dpdk.org
Cc: stable@dpdk.org, gage.eads@intel.com,
	Olivier Matz <olivier.matz@6wind.com>
Subject: [dpdk-dev] [PATCH] stack: reload head when pop fails (generic)
Date: Thu, 19 Aug 2021 11:39:14 +0200	[thread overview]
Message-ID: <20210819093915.5227-1-julien.meunier@nokia.com> (raw)

The previous fix 18effad9cfa7 ("stack: reload head when pop fails") only
changed C11 implementation, not generic implementation.

List head must be loaded right before continue (when failed to find the
new head). Without this, one thread might keep trying and failing to pop
items without ever loading the new correct head.

Fixes: 3340202f5954 ("stack: add lock-free implementation")
Cc: gage.eads@intel.com
Cc: stable@dpdk.org

Signed-off-by: Julien Meunier <julien.meunier@nokia.com>
---
 lib/stack/rte_stack_lf_generic.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/stack/rte_stack_lf_generic.h b/lib/stack/rte_stack_lf_generic.h
index 4850a05ee7..7fa29cedb2 100644
--- a/lib/stack/rte_stack_lf_generic.h
+++ b/lib/stack/rte_stack_lf_generic.h
@@ -128,8 +128,10 @@ __rte_stack_lf_pop_elems(struct rte_stack_lf_list *list,
 		/* If NULL was encountered, the list was modified while
 		 * traversing it. Retry.
 		 */
-		if (i != num)
+		if (i != num) {
+			old_head = list->head;
 			continue;
+		}
 
 		new_head.top = tmp;
 		new_head.cnt = old_head.cnt + 1;
-- 
2.17.1


             reply	other threads:[~2021-08-19  9:39 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19  9:39 Julien Meunier [this message]
2021-09-21 16:17 ` [dpdk-dev] [PATCH v2] stack: fix reload head when pop fails Julien Meunier
2021-09-24  8:57   ` Olivier Matz
2021-09-27 15:47     ` [dpdk-dev] [dpdk-stable] " Thomas Monjalon

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