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authorMartin Kepplinger <martink@posteo.de>2015-03-23 13:59:46 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-25 11:36:38 +0100
commit03190c67ff72b5c56b24266762ab8abe68970f45 (patch)
treeef65dc83f28caa0cf100c47165b1ce4837d0ab53 /drivers/char/misc.c
parentab3ae0096a6d31e1b244c5c5155f48ef3700329e (diff)
char: misc: document behaviour of open()
an open syscall now assignes file->private_data to a pointer to the miscdevice structure. This reminds people not to duplicate code if they want this and not to depend on it being NULL. Signed-off-by: Martin Kepplinger <martink@posteo.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char/misc.c')
-rw-r--r--drivers/char/misc.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index ffa97d261cf3..c892c296a4de 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -169,7 +169,9 @@ static const struct file_operations misc_fops = {
* the minor number requested is used.
*
* The structure passed is linked into the kernel and may not be
- * destroyed until it has been unregistered.
+ * destroyed until it has been unregistered. By default, an open()
+ * syscall to the device sets file->private_data to point to the
+ * structure. Drivers don't need open in fops for this.
*
* A zero is returned on success and a negative errno code for
* failure.