netdev - [PATCH v4 29/40] net: smc: optimize smc_wr_tx_get_free_slot

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Message-ID: <20240620175703.605111-30-yury.norov@gmail.com>
Date: Thu, 20 Jun 2024 10:56:52 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Karsten Graul <kgraul@...ux.ibm.com>,
	Wenjia Zhang <wenjia@...ux.ibm.com>,
	Jan Karcher <jaka@...ux.ibm.com>,
	"D. Wythe" <alibuda@...ux.alibaba.com>,
	Tony Lu <tonylu@...ux.alibaba.com>,
	Wen Gu <guwen@...ux.alibaba.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	linux-s390@...r.kernel.org,
	netdev@...r.kernel.org
Cc: Yury Norov <yury.norov@...il.com>,
	Alexey Klimov <alexey.klimov@...aro.org>,
	Bart Van Assche <bvanassche@....org>,
	Jan Kara <jack@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Wilcox <willy@...radead.org>,
	Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Sergey Shtylyov <s.shtylyov@....ru>,
	Alexandra Winter <wintera@...ux.ibm.com>
Subject: [PATCH v4 29/40] net: smc: optimize smc_wr_tx_get_free_slot_index()

Simplify the function by using find_and_set_bit() and make it a simple
almost one-liner.

While here, drop explicit initialization of *idx, because it's already
initialized by the caller in case of ENOLINK, or set properly with
->wr_tx_mask, if nothing is found, in case of EBUSY.

CC: Tony Lu <tonylu@...ux.alibaba.com>
Signed-off-by: Yury Norov <yury.norov@...il.com>
Reviewed-by: Alexandra Winter <wintera@...ux.ibm.com>
Reviewed-by: Wen Gu <guwen@...ux.alibaba.com>
---
 net/smc/smc_wr.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 0021065a600a..941c2434a021 100644
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -23,6 +23,7 @@
  */
 
 #include <linux/atomic.h>
+#include <linux/find_atomic.h>
 #include <linux/hashtable.h>
 #include <linux/wait.h>
 #include <rdma/ib_verbs.h>
@@ -170,15 +171,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
 
 static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
 {
-	*idx = link->wr_tx_cnt;
 	if (!smc_link_sendable(link))
 		return -ENOLINK;
-	for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
-		if (!test_and_set_bit(*idx, link->wr_tx_mask))
-			return 0;
-	}
-	*idx = link->wr_tx_cnt;
-	return -EBUSY;
+
+	*idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
+	return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
 }
 
 /**
-- 
2.43.0