Messages in this thread | | | Date | Thu, 2 Sep 2021 18:34:02 +0200 | From | Greg KH <> | Subject | Re: [PATCH 1/1] debugfs: use IS_ERR to check for error |
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On Thu, Sep 02, 2021 at 05:10:24PM +0200, Christian König wrote: > Am 02.09.21 um 14:20 schrieb Greg KH: > > On Thu, Sep 02, 2021 at 02:03:12PM +0200, Christian König wrote: > > > > > > Am 02.09.21 um 12:38 schrieb Greg KH: > > > > On Thu, Sep 02, 2021 at 12:29:17PM +0200, Nirmoy Das wrote: > > > > > debugfs_create_file() returns encoded error so > > > > > use IS_ERR for checking return value. > > > > > > > > > > References: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2F-%2Fissues%2F1686&data=04%7C01%7Cchristian.koenig%40amd.com%7Cffc1109aeb744082181b08d96e0c06db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637661820207117289%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=6NDHX9sEhGF2jakVfUJ7Qurql6UAdNpFQZ6XvCjwz0E%3D&reserved=0 > > > > > Signed-off-by: Nirmoy Das <nirmoy.das@amd.com> > > > > > --- > > > > > fs/debugfs/inode.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c > > > > > index 8129a430d789..2f117c57160d 100644 > > > > > --- a/fs/debugfs/inode.c > > > > > +++ b/fs/debugfs/inode.c > > > > > @@ -528,7 +528,7 @@ void debugfs_create_file_size(const char *name, umode_t mode, > > > > > { > > > > > struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); > > > > > - if (de) > > > > > + if (!IS_ERR(de)) > > > > > d_inode(de)->i_size = file_size; > > > > > } > > > > > EXPORT_SYMBOL_GPL(debugfs_create_file_size); > > > > > -- > > > > > 2.32.0 > > > > > > > > > Ah, good catch, I'll queue this up after 5.15-rc1 is out, thanks! > > > Thinking more about this if I'm not completely mistaken > > > debugfs_create_file() returns -ENODEV when debugfs is disabled and NULL on > > > any other error. > > How can this function be called if debugfs is not enabled in the system > > configuration? This _is_ the debugfs core code. > > Well, that's what I meant. The original code is correct and Nirmoy's patch > here is breaking it.
Ah, yes, sorry, you are right. This function can not return an error value, if something went wrong, the result will always be NULL.
> Nirmoys other patch is for a driver and there the function can indeed return > both error code and NULL.
You should never be checking this stuff in a caller anyway, so no, don't do it there either.
thanks,
greg k-h
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