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authorJakub Kicinski <kuba@kernel.org>2023-12-07 17:47:58 -0800
committerJakub Kicinski <kuba@kernel.org>2023-12-07 17:53:17 -0800
commit2483e7f04ce0e97c69b27d28ebce7a2320b7a7a6 (patch)
treea45d2e6897a32eaee4b6a5b3b84617d5ca52f4b2 /lib/objpool.c
parent87e839c82cc36346a2cd183ca941316902110716 (diff)
parent5e3f5b81de80c98338bcb47c233aebefee5a4801 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR. Conflicts: drivers/net/ethernet/stmicro/stmmac/dwmac5.c drivers/net/ethernet/stmicro/stmmac/dwmac5.h drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c drivers/net/ethernet/stmicro/stmmac/hwif.h 37e4b8df27bc ("net: stmmac: fix FPE events losing") c3f3b97238f6 ("net: stmmac: Refactor EST implementation") https://lore.kernel.org/all/20231206110306.01e91114@canb.auug.org.au/ Adjacent changes: net/ipv4/tcp_ao.c 9396c4ee93f9 ("net/tcp: Don't store TCP-AO maclen on reqsk") 7b0f570f879a ("tcp: Move TCP-AO bits from cookie_v[46]_check() to tcp_ao_syncookie().") Signed-off-by: Jakub Kicinski <kuba@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]);