Messages in this thread |  | | From | Khalid Masum <> | Date | Mon, 18 Jul 2022 00:34:19 +0600 | Subject | Re: [PATCH] Bluetooth: hci_core: Use ERR_PTR instead of NULL |
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On Sun, Jul 17, 2022 at 10:17 PM Pavel Skripkin <paskripkin@gmail.com> wrote: > > Hi Khalid, > > Khalid Masum <khalid.masum.92@gmail.com> says: > > Failure of kzalloc to allocate memory is not reported. Return Error > > pointer to ENOMEM if memory allocation fails. This will increase > > readability and will make the function easier to use in future. > > > > Signed-off-by: Khalid Masum <khalid.masum.92@gmail.com> > > --- > > [snip] > > > index a0f99baafd35..ea50767e02bf 100644 > > --- a/net/bluetooth/hci_core.c > > +++ b/net/bluetooth/hci_core.c > > @@ -2419,7 +2419,7 @@ struct hci_dev *hci_alloc_dev_priv(int sizeof_priv) > > > > hdev = kzalloc(alloc_size, GFP_KERNEL); > > if (!hdev) > > - return NULL; > > + return ERR_PTR(-ENOMEM); > > > > This will break all callers of hci_alloc_dev(). All callers expect NULL > in case of an error, so you will leave them with wrong pointer.
You are right. All callers of hci_alloc_dev() need to be able to handle the error pointer. I shall send a V2 with all the callers of hci_alloc_dev handling the ERR_PTR.
> Also, allocation functionS return an error only in case of ENOMEM, so > initial code is fine, IMO >
I think it makes the memory allocation error handling look to be a bit different from what we usually do while allocating memory which is, returning an error or an error pointer. Here we are returning a NULL without any context, making it a bit unreadable. So I think returning an error pointer is better. If I am not mistaken, this also complies with the return convention: https://www.kernel.org/doc/htmldocs/kernel-hacking/convention-returns.html
> > Thanks, > --Pavel Skripkin
Thanks, -- Khalid Masum
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