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* [PATCH] mtd: ck804xrom: fix missing pci device put in error paths
@ 2020-08-21  7:05 James Bond
  2020-08-27 12:46 ` Miquel Raynal
  0 siblings, 1 reply; 4+ messages in thread
From: James Bond @ 2020-08-21  7:05 UTC (permalink / raw)
  To: jameslouisebond
  Cc: Miquel Raynal, Richard Weinberger, Vignesh Raghavendra,
	Arnd Bergmann, Ryan Jackson, David Woodhouse, linux-mtd,
	linux-kernel

pci_dev_get increases the refcount of "pdev".
In the error paths, pci_dev_put should be called
to handle the "pdev" and decrease the corresponding refcount.

Fixes: 90afffc8bd79 ("[MTD] [MAPS] Support for BIOS flash chips on the nvidia ck804 southbridge")
Signed-off-by: James Bond <jameslouisebond@gmail.com>
---
 drivers/mtd/maps/ck804xrom.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mtd/maps/ck804xrom.c b/drivers/mtd/maps/ck804xrom.c
index 460494212f6a..16af8b5ee653 100644
--- a/drivers/mtd/maps/ck804xrom.c
+++ b/drivers/mtd/maps/ck804xrom.c
@@ -195,6 +195,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
 	if (!window->virt) {
 		printk(KERN_ERR MOD_NAME ": ioremap(%08lx, %08lx) failed\n",
 			window->phys, window->size);
+		pci_dev_put(pdev);
 		goto out;
 	}
 
@@ -222,6 +223,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
 
 		if (!map) {
 			printk(KERN_ERR MOD_NAME ": kmalloc failed");
+			pci_dev_put(pdev);
 			goto out;
 		}
 		memset(map, 0, sizeof(*map));
@@ -295,6 +297,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
 		if (mtd_device_register(map->mtd, NULL, 0)) {
 			map_destroy(map->mtd);
 			map->mtd = NULL;
+			pci_dev_put(pdev);
 			goto out;
 		}
 
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] mtd: ck804xrom: fix missing pci device put in error paths
  2020-08-21  7:05 [PATCH] mtd: ck804xrom: fix missing pci device put in error paths James Bond
@ 2020-08-27 12:46 ` Miquel Raynal
  2020-08-29  2:28   ` James Bond
  0 siblings, 1 reply; 4+ messages in thread
From: Miquel Raynal @ 2020-08-27 12:46 UTC (permalink / raw)
  To: James Bond
  Cc: Vignesh Raghavendra, Arnd Bergmann, Ryan Jackson,
	Richard Weinberger, linux-kernel, linux-mtd, David Woodhouse

Hi James,

James Bond <jameslouisebond@gmail.com> wrote on Fri, 21 Aug 2020
02:05:36 -0500:

> pci_dev_get increases the refcount of "pdev".
> In the error paths, pci_dev_put should be called
> to handle the "pdev" and decrease the corresponding refcount.
> 
> Fixes: 90afffc8bd79 ("[MTD] [MAPS] Support for BIOS flash chips on the nvidia ck804 southbridge")
> Signed-off-by: James Bond <jameslouisebond@gmail.com>
> ---
>  drivers/mtd/maps/ck804xrom.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/mtd/maps/ck804xrom.c b/drivers/mtd/maps/ck804xrom.c
> index 460494212f6a..16af8b5ee653 100644
> --- a/drivers/mtd/maps/ck804xrom.c
> +++ b/drivers/mtd/maps/ck804xrom.c
> @@ -195,6 +195,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
>  	if (!window->virt) {
>  		printk(KERN_ERR MOD_NAME ": ioremap(%08lx, %08lx) failed\n",
>  			window->phys, window->size);
> +		pci_dev_put(pdev);
>  		goto out;
>  	}
>  
> @@ -222,6 +223,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
>  
>  		if (!map) {
>  			printk(KERN_ERR MOD_NAME ": kmalloc failed");
> +			pci_dev_put(pdev);
>  			goto out;
>  		}
>  		memset(map, 0, sizeof(*map));
> @@ -295,6 +297,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
>  		if (mtd_device_register(map->mtd, NULL, 0)) {
>  			map_destroy(map->mtd);
>  			map->mtd = NULL;
> +			pci_dev_put(pdev);
>  			goto out;
>  		}
>  

I suppose in these three cases, the window->maps list will be empty and
you will end up returning -ENODEV and the bottom of the function? If
yes, it woudl probably be better to move these pci_dev_put() calls to
this location.

Otherwise, it might bit interesting to clean up a little bit the error
path and perhaps have a distinct success vs. failure path.


Thanks,
Miquèl

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] mtd: ck804xrom: fix missing pci device put in error paths
  2020-08-27 12:46 ` Miquel Raynal
@ 2020-08-29  2:28   ` James Bond
  2020-08-31 12:00     ` Miquel Raynal
  0 siblings, 1 reply; 4+ messages in thread
From: James Bond @ 2020-08-29  2:28 UTC (permalink / raw)
  To: Miquel Raynal
  Cc: Vignesh Raghavendra, Arnd Bergmann, Ryan Jackson,
	Richard Weinberger, linux-kernel, linux-mtd, David Woodhouse

Hi Miquèl,
Thanks for your feedback.
I have just rechecked this function and find that "pdev" currently is
already put
inside ck804xrom_cleanup, so my previous patch is meaningless...
The current calling order is like:

window->pdev = pci_dev_get(pdev);
...
    ck804xrom_cleanup(window)
             ->
                  pci_dev_put(window->pdev);
And sorry for bothering you.
Thanks,
James

On Thu, Aug 27, 2020 at 7:46 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>
> Hi James,
>
> James Bond <jameslouisebond@gmail.com> wrote on Fri, 21 Aug 2020
> 02:05:36 -0500:
>
> > pci_dev_get increases the refcount of "pdev".
> > In the error paths, pci_dev_put should be called
> > to handle the "pdev" and decrease the corresponding refcount.
> >
> > Fixes: 90afffc8bd79 ("[MTD] [MAPS] Support for BIOS flash chips on the nvidia ck804 southbridge")
> > Signed-off-by: James Bond <jameslouisebond@gmail.com>
> > ---
> >  drivers/mtd/maps/ck804xrom.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/mtd/maps/ck804xrom.c b/drivers/mtd/maps/ck804xrom.c
> > index 460494212f6a..16af8b5ee653 100644
> > --- a/drivers/mtd/maps/ck804xrom.c
> > +++ b/drivers/mtd/maps/ck804xrom.c
> > @@ -195,6 +195,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
> >       if (!window->virt) {
> >               printk(KERN_ERR MOD_NAME ": ioremap(%08lx, %08lx) failed\n",
> >                       window->phys, window->size);
> > +             pci_dev_put(pdev);
> >               goto out;
> >       }
> >
> > @@ -222,6 +223,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
> >
> >               if (!map) {
> >                       printk(KERN_ERR MOD_NAME ": kmalloc failed");
> > +                     pci_dev_put(pdev);
> >                       goto out;
> >               }
> >               memset(map, 0, sizeof(*map));
> > @@ -295,6 +297,7 @@ static int __init ck804xrom_init_one(struct pci_dev *pdev,
> >               if (mtd_device_register(map->mtd, NULL, 0)) {
> >                       map_destroy(map->mtd);
> >                       map->mtd = NULL;
> > +                     pci_dev_put(pdev);
> >                       goto out;
> >               }
> >
>
> I suppose in these three cases, the window->maps list will be empty and
> you will end up returning -ENODEV and the bottom of the function? If
> yes, it woudl probably be better to move these pci_dev_put() calls to
> this location.
>
> Otherwise, it might bit interesting to clean up a little bit the error
> path and perhaps have a distinct success vs. failure path.
>
>
> Thanks,
> Miquèl

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] mtd: ck804xrom: fix missing pci device put in error paths
  2020-08-29  2:28   ` James Bond
@ 2020-08-31 12:00     ` Miquel Raynal
  0 siblings, 0 replies; 4+ messages in thread
From: Miquel Raynal @ 2020-08-31 12:00 UTC (permalink / raw)
  To: James Bond
  Cc: Vignesh Raghavendra, Arnd Bergmann, Ryan Jackson,
	Richard Weinberger, linux-kernel, linux-mtd, David Woodhouse

Hi James,

James Bond <jameslouisebond@gmail.com> wrote on Fri, 28 Aug 2020
21:28:40 -0500:

> Hi Miquèl,
> Thanks for your feedback.
> I have just rechecked this function and find that "pdev" currently is
> already put
> inside ck804xrom_cleanup, so my previous patch is meaningless...
> The current calling order is like:
> 
> window->pdev = pci_dev_get(pdev);
> ...
>     ck804xrom_cleanup(window)
>              ->  
>                   pci_dev_put(window->pdev);
> And sorry for bothering you.

Ok that's fine, thanks anyway!

Miquèl

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-08-31 12:00 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-08-21  7:05 [PATCH] mtd: ck804xrom: fix missing pci device put in error paths James Bond
2020-08-27 12:46 ` Miquel Raynal
2020-08-29  2:28   ` James Bond
2020-08-31 12:00     ` Miquel Raynal

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