drivers/staging/kpc2000/kpc_dma/fileops.c:60:8-26: WARNING: casting value returned by memory allocation function to (struct aio_cb_data *) is useless.

drivers/staging/kpc2000/kpc_dma/fileops.c:60:8-26: WARNING: casting value returned by memory allocation function to (struct aio_cb_data *) is useless.

[kbuild test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   5ac94332248ee017964ba368cdda4ce647e3aba7
commit: 7df95299b94a63ec67a6389fc02dc25019a80ee8 staging: kpc2000: Add DMA driver
date:   3 weeks ago

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>


coccinelle warnings: (new ones prefixed by >>)

>> drivers/staging/kpc2000/kpc_dma/fileops.c:60:8-26: WARNING: casting value returned by memory allocation function to (struct aio_cb_data *) is useless.

Please review and possibly fold the followup patch.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[PATCH] staging: kpc2000: fix alloc_cast.cocci warnings

[kbuild test robot]

From: kbuild test robot <lkp@intel.com>

drivers/staging/kpc2000/kpc_dma/fileops.c:60:8-26: WARNING: casting value returned by memory allocation function to (struct aio_cb_data *) is useless.

 Remove casting the values returned by memory allocation functions
 like kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc.

Semantic patch information:
 This makes an effort to find cases of casting of values returned by
 kmalloc, kzalloc, kcalloc, kmem_cache_alloc, kmem_cache_zalloc,
 kmem_cache_alloc_node, kmalloc_node and kzalloc_node and removes
 the casting as it is not required. The result in the patch case may
 need some reformatting.

Generated by: scripts/coccinelle/api/alloc/alloc_cast.cocci

Fixes: 7df95299b94a ("staging: kpc2000: Add DMA driver")
CC: Matt Sickler <Matt.Sickler@daktronics.com>
Signed-off-by: kbuild test robot <lkp@intel.com>
---

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   5ac94332248ee017964ba368cdda4ce647e3aba7
commit: 7df95299b94a63ec67a6389fc02dc25019a80ee8 staging: kpc2000: Add DMA driver

 fileops.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -57,7 +57,7 @@ int  kpc_dma_transfer(struct dev_private
 	
 	dev_dbg(&priv->ldev->pldev->dev, "kpc_dma_transfer(priv = [%p], kcb = [%p], iov_base = [%p], iov_len = %ld) ldev = [%p]\n", priv, kcb, (void*)iov_base, iov_len, ldev);
 	
-	acd = (struct aio_cb_data *) kzalloc(sizeof(struct aio_cb_data), GFP_KERNEL);
+	acd = kzalloc(sizeof(struct aio_cb_data), GFP_KERNEL);
 	if (!acd){
 		dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the aio data\n");
 		return -ENOMEM;

Re: [PATCH] staging: kpc2000: fix alloc_cast.cocci warnings

[Greg Kroah-Hartman]

On Wed, May 15, 2019 at 08:16:15PM +0800, kbuild test robot wrote:
> From: kbuild test robot <lkp@intel.com>
> 
> drivers/staging/kpc2000/kpc_dma/fileops.c:60:8-26: WARNING: casting value returned by memory allocation function to (struct aio_cb_data *) is useless.
> 
>  Remove casting the values returned by memory allocation functions
>  like kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc.
> 
> Semantic patch information:
>  This makes an effort to find cases of casting of values returned by
>  kmalloc, kzalloc, kcalloc, kmem_cache_alloc, kmem_cache_zalloc,
>  kmem_cache_alloc_node, kmalloc_node and kzalloc_node and removes
>  the casting as it is not required. The result in the patch case may
>  need some reformatting.
> 
> Generated by: scripts/coccinelle/api/alloc/alloc_cast.cocci
> 
> Fixes: 7df95299b94a ("staging: kpc2000: Add DMA driver")
> CC: Matt Sickler <Matt.Sickler@daktronics.com>
> Signed-off-by: kbuild test robot <lkp@intel.com>
> ---
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   5ac94332248ee017964ba368cdda4ce647e3aba7
> commit: 7df95299b94a63ec67a6389fc02dc25019a80ee8 staging: kpc2000: Add DMA driver
> 
>  fileops.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/drivers/staging/kpc2000/kpc_dma/fileops.c
> +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
> @@ -57,7 +57,7 @@ int  kpc_dma_transfer(struct dev_private
>  	
>  	dev_dbg(&priv->ldev->pldev->dev, "kpc_dma_transfer(priv = [%p], kcb = [%p], iov_base = [%p], iov_len = %ld) ldev = [%p]\n", priv, kcb, (void*)iov_base, iov_len, ldev);
>  	
> -	acd = (struct aio_cb_data *) kzalloc(sizeof(struct aio_cb_data), GFP_KERNEL);
> +	acd = kzalloc(sizeof(struct aio_cb_data), GFP_KERNEL);
>  	if (!acd){
>  		dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the aio data\n");
>  		return -ENOMEM;

Already fixed in my staging-testing branch, thanks.

greg k-h