Messages in this thread | | | Date | Mon, 9 Dec 2013 10:39:27 -0800 | From | Greg KH <> | Subject | Re: [PATCH v3] xen/debugfs: Check debugfs initialization before using it |
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On Mon, Dec 09, 2013 at 09:49:36PM +0800, Ethan Zhao wrote: > On Mon, Dec 9, 2013 at 7:19 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > > On Mon, Dec 09, 2013 at 05:56:52PM +0800, Ethan Zhao wrote: > >> From: "ethan.zhao" <ethan.kernel@gmail.com> > >> > >> Should check debugfs initialization with debugfs_initialized() before using it, > >> Because if it isn't initialized, the return value of fake debugfs_create_dir() etc > >> functions would be ERR_PTR(-ENODEV), checking with NULL will not work. > >> > >> V3: add warning message when debugfs not configured or disabled. > > > > That's not what this patch does... > > > >> Signed-off-by: ethan.zhao <ethan.kernel@gmail.com> > >> --- > >> arch/x86/xen/debugfs.c | 6 ++++++ > >> 1 file changed, 6 insertions(+) > >> > >> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c > >> index c8377fb..85c0e0e 100644 > >> --- a/arch/x86/xen/debugfs.c > >> +++ b/arch/x86/xen/debugfs.c > >> @@ -9,12 +9,18 @@ static struct dentry *d_xen_debug; > >> > >> struct dentry * __init xen_init_debugfs(void) > >> { > >> + if (!debugfs_initialized()) { > >> + d_xen_debug = NULL; > >> + goto nodebugfs; > >> + } > > > > Again, why is this even needed? > > > > What problem in the existing code are you trying to solve? > > > What I want to ask who is so smart and fake some many functions when > CONFIG_DEBUG_FS is not configured/defined and the build could pass > without any error ?
That's the way this has always worked.
> What is the motive make him wrote some many fake function and why he > wrote the debugfs_initialized() function seem 'useless' at all ?
To make the caller code easier, and smaller, and to not care if debugfs is enabled in the kernel build or not at all.
Ok, I answered your questions, now care to answer mine?
greg k-h
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