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authorLeon Romanovsky <leon@kernel.org>2023-12-12 09:04:59 +0200
committerLeon Romanovsky <leon@kernel.org>2023-12-12 09:04:59 +0200
commitafcda192dbab7df48dfedb1813a6d03bf6bd4996 (patch)
tree270d0e74520e0f8d17da34bbdd8d91dec47f3585 /lib/objpool.c
parent07f830ae4913d0b986c8c0ff88a7d597948b9bd8 (diff)
parentd727d27db536faea7178290c677cc0567f647231 (diff)
Expose c0 and SW encap ICM for RDMA
These two series from Mark and Shun extend RDMA mlx5 API. Mark's series provides c0 register used to match egress traffic sent by local device. Shun's series adds new type for ICM area. Link: https://lore.kernel.org/all/cover.1701871118.git.leon@kernel.org Signed-off-by: Leon Romanovsky <leon@kernel.org>
Diffstat (limited to 'lib/objpool.c')
-rw-r--r--lib/objpool.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/lib/objpool.c b/lib/objpool.c
index ce0087f64400..cfdc02420884 100644
--- a/lib/objpool.c
+++ b/lib/objpool.c
@@ -201,6 +201,23 @@ static inline void *objpool_try_get_slot(struct objpool_head *pool, int cpu)
while (head != READ_ONCE(slot->last)) {
void *obj;
+ /*
+ * data visibility of 'last' and 'head' could be out of
+ * order since memory updating of 'last' and 'head' are
+ * performed in push() and pop() independently
+ *
+ * before any retrieving attempts, pop() must guarantee
+ * 'last' is behind 'head', that is to say, there must
+ * be available objects in slot, which could be ensured
+ * by condition 'last != head && last - head <= nr_objs'
+ * that is equivalent to 'last - head - 1 < nr_objs' as
+ * 'last' and 'head' are both unsigned int32
+ */
+ if (READ_ONCE(slot->last) - head - 1 >= pool->nr_objs) {
+ head = READ_ONCE(slot->head);
+ continue;
+ }
+
/* obj must be retrieved before moving forward head */
obj = READ_ONCE(slot->entries[head & slot->mask]);