linux-kernel - [PATCH] w1: Fix slave count on W1 bus

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Message-Id: <20170528071351.6678-1-minimumlaw@rambler.ru>
Date:   Sun, 28 May 2017 10:13:51 +0300
From:   "Alex A. Mihaylov" <minimumlaw@...bler.ru>
To:     Evgeniy Polyakov <zbr@...emap.net>, linux-kernel@...r.kernel.org
Cc:     "Alex A. Mihaylov" <minimumlaw@...bler.ru>
Subject: [PATCH] w1: Fix slave count on W1 bus

OneWire bus have very fast algorith for exchange with single slave
device. Fix incorrect count of slave devices on connect second slave
device. This case on probe() step we need use generic (multislave)
functions for read/write slave device.

Signed-off-by: Alex A. Mihaylov <minimumlaw@...bler.ru>
---
 drivers/w1/w1.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 90a3d93..5b8b976 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -731,6 +731,7 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 	memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 	atomic_set(&sl->refcnt, 1);
 	atomic_inc(&sl->master->refcnt);
+	dev->slave_count++;

 	/* slave modules need to be loaded in a context with unlocked mutex */
 	mutex_unlock(&dev->mutex);
@@ -750,11 +751,11 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)

 	sl->family = f;

-
 	err = __w1_attach_slave_device(sl);
 	if (err < 0) {
 		dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 			 sl->name);
+		dev->slave_count--;
 		w1_family_put(sl->family);
 		atomic_dec(&sl->master->refcnt);
 		kfree(sl);
@@ -762,7 +763,6 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 	}

 	sl->ttl = dev->slave_ttl;
-	dev->slave_count++;

 	memcpy(msg.id.id, rn, sizeof(msg.id));
 	msg.type = W1_SLAVE_ADD;
-- 
2.8.4 (Apple Git-73)