linux-kernel - [PATCH 19/35] W1: w1_int.c use first available master number

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Date:	Fri, 28 Mar 2008 07:26:43 -0500
From:	David Fries <david@...es.net>
To:	linux-kernel@...r.kernel.org
Cc:	Evgeniy Polyakov <johnpol@....mipt.ru>
Subject: [PATCH 19/35] W1: w1_int.c use first available master number

w1_int.c 1.8
Follow the example of other devices (like the joystick device).  Pick           the first available id for each detected device.  For a one device
system suspending and resuming would at least keep the 1 id.  It would
at least make it easier on the user program.  That and it would reduce
holes, plugin master, plugin master, remove 2nd master, plug in
master, then you have 1, 2 intead of 1, 3.

Signed-off-by: David Fries <david@...es.net>
---
 drivers/w1/w1_int.c |   31 +++++++++++++++++++++++++------
 1 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index f1806e2..9ec468a 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -29,7 +29,6 @@
 #include "w1_netlink.h"
 #include "w1_int.h"
 
-static u32 w1_ids = 1;
 static int w1_search_count = -1; /* Default is continual scan */
 module_param_named(search_count, w1_search_count, int, 0);
 
@@ -98,9 +97,10 @@ static void w1_free_dev(struct w1_master *dev)
 
 int w1_add_master_device(struct w1_bus_master *master)
 {
-	struct w1_master *dev;
+	struct w1_master *dev, *entry;
 	int retval = 0;
 	struct w1_netlink_msg msg;
+	int id, found;
 
         /* validate minimum functionality */
         if (!(master->touch_bit && master->reset_bus) &&
@@ -122,13 +122,32 @@ int w1_add_master_device(struct w1_bus_master *master)
 		master->set_pullup=NULL;
 	}
 
-	dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
-	if (!dev)
+	/* Lock until the device is added (or not) to w1_masters. */
+	mutex_lock(&w1_mlock);
+	/* Search for the first available id (starting at 1). */
+	id=0;
+	do {
+		++id;
+		found=0;
+		list_for_each_entry(entry, &w1_masters, w1_master_entry) {
+			if(entry->id==id) {
+				found=1;
+				break;
+			}
+		}
+	}while(found);
+
+	dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
+	if (!dev) {
+		mutex_unlock(&w1_mlock);
 		return -ENOMEM;
+	}
 
 	retval =  w1_create_master_attributes(dev);
-	if (retval)
+	if (retval) {
+		mutex_unlock(&w1_mlock);
 		goto err_out_free_dev;
+	}
 
 	memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
 
@@ -140,10 +159,10 @@ int w1_add_master_device(struct w1_bus_master *master)
 		dev_err(&dev->dev,
 			 "Failed to create new kernel thread. err=%d\n",
 			 retval);
+		mutex_unlock(&w1_mlock);
 		goto err_out_rm_attr;
 	}
 
-	mutex_lock(&w1_mlock);
 	list_add(&dev->w1_master_entry, &w1_masters);
 	mutex_unlock(&w1_mlock);
 
-- 
1.4.4.4

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