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authorWolfram Sang <w.sang@pengutronix.de>2010-05-04 11:09:27 +0200
committerJean Delvare <khali@linux-fr.org>2010-05-04 11:09:27 +0200
commite4a7b9b04de15f6b63da5ccdd373ffa3057a3681 (patch)
tree7f2f49df9dc66b334b85f83347df03d2b0d0a721
parentd93ac51c7a129db7a1431d859a3ef45a0b1f3fc5 (diff)
i2c-core: Erase pointer to clientdata on removal
After discovering that a lot of i2c-drivers leave the pointer to their clientdata dangling, it was decided to let the core handle this issue. It is assumed that the core may access the private data after remove() as there are no guarantees for the lifetime of such pointers anyhow (see thread starting at http://lkml.org/lkml/2010/3/21/68) Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Jean Delvare <khali@linux-fr.org>
-rw-r--r--Documentation/i2c/writing-clients5
-rw-r--r--drivers/i2c/i2c-core.c8
2 files changed, 11 insertions, 2 deletions
diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index 3219ee0dbfe..5ebf5af1d71 100644
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -74,6 +74,11 @@ structure at all. You should use this to keep device-specific data.
/* retrieve the value */
void *i2c_get_clientdata(const struct i2c_client *client);
+Note that starting with kernel 2.6.34, you don't have to set the `data' field
+to NULL in remove() or if probe() failed anymore. The i2c-core does this
+automatically on these occasions. Those are also the only times the core will
+touch this field.
+
Accessing the client
====================
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 3202a86f420..b9306b1a6ba 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -117,8 +117,10 @@ static int i2c_device_probe(struct device *dev)
dev_dbg(dev, "probe\n");
status = driver->probe(client, i2c_match_id(driver->id_table, client));
- if (status)
+ if (status) {
client->driver = NULL;
+ i2c_set_clientdata(client, NULL);
+ }
return status;
}
@@ -139,8 +141,10 @@ static int i2c_device_remove(struct device *dev)
dev->driver = NULL;
status = 0;
}
- if (status == 0)
+ if (status == 0) {
client->driver = NULL;
+ i2c_set_clientdata(client, NULL);
+ }
return status;
}