Messages in this thread | | | Date | Tue, 21 Sep 2021 09:03:44 +0200 | From | Greg KH <> | Subject | Re: [PATCH 1/1] debugfs: use IS_ERR to check for error |
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On Fri, Sep 03, 2021 at 08:27:34AM +0200, Christian König wrote: > Am 02.09.21 um 19:01 schrieb Das, Nirmoy: > > > > On 9/2/2021 6:34 PM, Greg KH wrote: > > > 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%7Cnirmoy.das%40amd.com%7C7a1f1095c0d64416576c08d96e2f7b38%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637661973378236086%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=g9BQRJG8gvjGFq6oj5vk9PCemQ39U19CLmkMNHVUafg%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. > > > > > > I just realized that we don't return NULL on error anymore: > > > > commit ff9fb72bc07705c00795ca48631f7fffe24d2c6b > > Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Date: Wed Jan 23 11:28:14 2019 +0100 > > > > debugfs: return error values, not NULL > > > > > > and the current doc also says "If an error occurs, ERR_PTR(-ERROR) will > > be returned." > > > > If I am not missing anything, this patch should be fine. > > Ah! Yes, now that makes sense. > > Looks like that my memory and the documentation under > https://www.kernel.org/doc/htmldocs/filesystems/API-debugfs-create-file.html > is outdated. > > I can update my memory, but I have no idea where this documentation comes > from and how to fix it.
I do not know how that is created either, it looks very old. This link should always be used instead: https://www.kernel.org/doc/html/latest/index.html
thanks,
greg k-h
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