Messages in this thread | | | Subject | Re: [PATCH 1/2] mtd: use put_device() if device_register fail | From | arvindY <> | Date | Sat, 17 Mar 2018 15:15:45 +0530 |
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On Wednesday 14 March 2018 08:06 PM, Boris Brezillon wrote: > On Fri, 9 Mar 2018 16:20:48 +0530 > Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > >> if device_register() returned an error! Always use put_device() >> to give up the reference initialized. >> >> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> >> --- >> drivers/mtd/mtdcore.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c >> index 28553c8..4d77ca2 100644 >> --- a/drivers/mtd/mtdcore.c >> +++ b/drivers/mtd/mtdcore.c >> @@ -586,6 +586,7 @@ int add_mtd_device(struct mtd_info *mtd) >> return 0; >> >> fail_added: >> + put_device(&mtd->dev); > Not sure this is a good idea: the put_device() call will trigger > an mtd_devtype->release(), which will in turn call device_destroy() on > something that does not exist yet. Not sure if this is a real problem, > but it does not look like the right thing to do. > yes, you are correct. No need to call put_device(). which can cause other problem.
>> of_node_put(mtd_get_of_node(mtd)); > You're referencing an object that is supposed to have been > freed/released by the put_device() call. Again, it's not really a > problem because in our case ->release() does not free the mtd object > (as is usually done in other parts of the kernel), but it still looks > wrong. It's probably better to move the of_node_put() and the below > idr_remove() call in the ->release() hook if you want to use > put_device(). > >> idr_remove(&mtd_idr, i); Sure, we can move put_device() below this. But need to check how we can add hook in release. > >> fail_locked: > > ~arvind
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