Re: [PATCHv2 02/16] iommu/omap: omap_iommu_attach() should return ENODEV, not NULL

Hi Laurent,

On Tuesday 25 February 2014 16:32:03 Suman Anna wrote:

quoted

On 02/25/2014 03:13 PM, Laurent Pinchart wrote:

quoted

On Thursday 13 February 2014 12:15:33 Suman Anna wrote:

quoted

From: Florian Vaussard <redacted>

omap_iommu_attach() returns NULL or ERR_PTR in case of error, but
omap_iommu_attach_dev() only checks for IS_ERR. Thus a NULL return value
(in case driver_find_device fails) will cause the kernel to panic when
omap_iommu_attach_dev() dereferences the pointer.

In such case, omap_iommu_attach() should return ENODEV, not NULL.

Signed-off-by: Florian Vaussard <redacted>
Acked-by: Suman Anna <redacted>
---

   drivers/iommu/omap-iommu.c | 4 ++--
   1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index fff2ffd..6272c36 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c

@@ -863,7 +863,7 @@ static int device_match_by_alias(struct device *dev,

void *data) **/

   static struct omap_iommu *omap_iommu_attach(const char *name, u32
   *iopgd)
   {
-	int err = -ENOMEM;
+	int err = -ENODEV;
   	struct device *dev;
   	struct omap_iommu *obj;

@@ -871,7 +871,7 @@ static struct omap_iommu *omap_iommu_attach(const

char *name, u32 *iopgd)
   				(void *)name,
   				device_match_by_alias);
   	if (!dev)
-		return NULL;
+		return ERR_PTR(err);

I would return ERR_PTR(-ENODEV) here, and remove the initialization at
declaration of err above.

The initialization at the beginning is also serving one another exit
path (a check for try_module_get), where err is not being set. If the
initialization is removed, then the err has to be set explicitly at the
other place. Let me know if you still want this changed.

The return value of iommu_enable() is unconditionally stored in err before the
try_module_get() call, so that code patch is buggy anyway and should be fixed.
I would still remove the initialization at declaration and assign -ENODEV to
err explicitly when try_module_get() fails before the goto err_module.

OK, I will fix this up.

regards
Suman