linux-kernel - [PATCH 04/41] maple_tree: remove extra smp_wmb() from mas_dead

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Message-ID: <20230109205336.3665937-5-surenb@google.com>
Date:   Mon,  9 Jan 2023 12:52:59 -0800
From:   Suren Baghdasaryan <surenb@...gle.com>
To:     akpm@...ux-foundation.org
Cc:     michel@...pinasse.org, jglisse@...gle.com, mhocko@...e.com,
        vbabka@...e.cz, hannes@...xchg.org, mgorman@...hsingularity.net,
        dave@...olabs.net, willy@...radead.org, liam.howlett@...cle.com,
        peterz@...radead.org, ldufour@...ux.ibm.com,
        laurent.dufour@...ibm.com, paulmck@...nel.org, luto@...nel.org,
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        leewalsh@...gle.com, posk@...gle.com, linux-mm@...ck.org,
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        linuxppc-dev@...ts.ozlabs.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, kernel-team@...roid.com,
        surenb@...gle.com, Liam Howlett <Liam.Howlett@...cle.com>
Subject: [PATCH 04/41] maple_tree: remove extra smp_wmb() from mas_dead_leaves()

From: Liam Howlett <Liam.Howlett@...cle.com>

The call to mte_set_dead_node() before the smp_wmb() already calls
smp_wmb() so this is not needed.  This is an optimization for the RCU
mode of the maple tree.

Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam Howlett <Liam.Howlett@...cle.com>
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
---
 lib/maple_tree.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index a11eea943f8d..d85291b19f86 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5510,7 +5510,6 @@ unsigned char mas_dead_leaves(struct ma_state *mas, void __rcu **slots,
 			break;
 
 		mte_set_node_dead(entry);
-		smp_wmb(); /* Needed for RCU */
 		node->type = type;
 		rcu_assign_pointer(slots[offset], node);
 	}
-- 
2.39.0