Re: [PATCH 7/9] s390/block/dcssblk: add error handling support for add_disk()

Gerald Schaefer
2021-09-06T11:44:24Z

On Fri, 3 Sep 2021 18:46:26 -0700
Luis Chamberlain <mcgrof@kernel.org> wrote:

> On Fri, Sep 03, 2021 at 04:08:48PM +0200, Heiko Carstens wrote:
> > On Thu, Sep 02, 2021 at 10:41:03AM -0700, Luis Chamberlain wrote:
> > > We never checked for errors on add_disk() as this function
> > > returned void. Now that this is fixed, use the shiny new
> > > error handling.
> > >
> > > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > > ---
> > > drivers/s390/block/dcssblk.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
> > > index 5be3d1c39a78..b0fd5009a12e 100644
> > > --- a/drivers/s390/block/dcssblk.c
> > > +++ b/drivers/s390/block/dcssblk.c
> > > @@ -696,7 +696,9 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
> > > }
> > >
> > > get_device(&dev_info->dev);
> > > - device_add_disk(&dev_info->dev, dev_info->gd, NULL);
> > > + rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL);
> > > + if (rc)
> > > + goto put_dev;
> >
> > This looks not correct to me. We seem to have now in case of an error:
> >
> > - reference count imbalance (= memory leak)
> > - dax cleanup is missing
>
> Care to provide an alternative?

See patch below:

From 7053b5f8c0a126c3ef450de3668d9963bd68ceaa Mon Sep 17 00:00:00 2001
From: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Date: Mon, 6 Sep 2021 13:18:53 +0200
Subject: [PATCH] s390/block/dcssblk: add error handling support for add_disk()

Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
---
drivers/s390/block/dcssblk.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 5be3d1c39a78..0741a9321712 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -696,7 +696,9 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
}

get_device(&dev_info->dev);
- device_add_disk(&dev_info->dev, dev_info->gd, NULL);
+ rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL);
+ if (rc)
+ goto out_dax;

switch (dev_info->segment_type) {
case SEG_TYPE_SR:
@@ -712,6 +714,10 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
rc = count;
goto out;

+out_dax:
+ put_device(&dev_info->dev);
+ kill_dax(dev_info->dax_dev);
+ put_dax(dev_info->dax_dev);
put_dev:
list_del(&dev_info->lh);
blk_cleanup_disk(dev_info->gd);
--
2.25.1