Commit 4ae717da authored Dec 14, 2009 by Thadeu Lima de Souza Cascardo Committed by Linus Torvalds Dec 15, 2009

drivers/char/misc.c: clear allocation bit in minor bitmap when device register fails



If there's a failure creating the device (because there's already one with
the same name, for example), the current implementation does not clear the
bit for the allocated minor and that number is lost for future
allocations.

Second, the test currently in misc_deregister is broken, since it does not
test for the 0 minor.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 603c4ba9

drivers/char/misc.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -214,6 +214,9 @@ int misc_register(struct miscdevice * misc)
		misc->this_device = device_create(misc_class, misc->parent, dev,
		misc, "%s", misc->name);
		if (IS_ERR(misc->this_device)) {
		int i = misc->minor;
		if (i < DYNAMIC_MINORS && i >= 0)
		misc_minors[i>>3] &= ~(1 << (i & 7));
		err = PTR_ERR(misc->this_device);
		goto out;
		}
		@@ -248,9 +251,8 @@ int misc_deregister(struct miscdevice *misc)
		mutex_lock(&misc_mtx);
		list_del(&misc->list);
		device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
		if (i < DYNAMIC_MINORS && i>0) {
		misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
		}
		if (i < DYNAMIC_MINORS && i >= 0)
		misc_minors[i>>3] &= ~(1 << (i & 7));
		mutex_unlock(&misc_mtx);
		return 0;
		}

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