Re: [PATCH] staging: gasket: Fix sparse "incorrect type in assignment" warnings.

[Laurence Rochfort]

 On Tue, Oct 09, 2018 at 03:13:03PM +0200, Greg Kroah-Hartman wrote:
> On Thu, Oct 04, 2018 at 06:52:25PM +0100, Laurence Rochfort wrote:
> > Silence the below sparse warnings by casting betwen u8 __iomem *, and
> > void *.
> > 
> > warning: incorrect type in assignment (different address spaces)
> >    expected unsigned char [noderef] [usertype] <asn:2>*virt_base
> >    got void *[assigned] mem
> > warning: incorrect type in argument 3 (different address spaces)
> >    expected void *cpu_addr
> >    got unsigned char [noderef] [usertype] <asn:2>*virt_base
> > 
> > Signed-off-by: Laurence Rochfort <laurence.rochfort@xxxxxxxxx>
> > ---
> >  drivers/staging/gasket/gasket_page_table.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/staging/gasket/gasket_page_table.c b/drivers/staging/gasket/gasket_page_table.c
> > index d4c5f8a..7f5e5b3 100644
> > --- a/drivers/staging/gasket/gasket_page_table.c
> > +++ b/drivers/staging/gasket/gasket_page_table.c
> > @@ -1278,7 +1278,7 @@ int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
> >  				 dma_addr_t *dma_address, u64 index)
> >  {
> >  	dma_addr_t handle;
> > -	void *mem;
> > +	u8 __iomem *mem;
> >  	int j;
> >  	unsigned int num_pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
> >  	const struct gasket_driver_desc *driver_desc =
> > @@ -1290,7 +1290,7 @@ int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
> >  	if (num_pages == 0)
> >  		return -EINVAL;
> >  
> > -	mem = dma_alloc_coherent(gasket_get_device(gasket_dev),
> > +	mem = (u8 __iomem *)dma_alloc_coherent(gasket_get_device(gasket_dev),
> >  				 num_pages * PAGE_SIZE, &handle, 0);
> >  	if (!mem)
> >  		goto nomem;
> > @@ -1325,7 +1325,7 @@ int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
> >  nomem:
> >  	if (mem) {
> >  		dma_free_coherent(gasket_get_device(gasket_dev),
> > -				  num_pages * PAGE_SIZE, mem, handle);
> > +				  num_pages * PAGE_SIZE, (void __force *)mem, handle);
> >  	}
> >  
> >  	if (gasket_dev->page_table[index]->coherent_pages) {
> > @@ -1353,7 +1353,7 @@ int gasket_free_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
> >  	if (gasket_dev->coherent_buffer.length_bytes) {
> >  		dma_free_coherent(gasket_get_device(gasket_dev),
> >  				  gasket_dev->coherent_buffer.length_bytes,
> > -				  gasket_dev->coherent_buffer.virt_base,
> > +				  (void __force *)gasket_dev->coherent_buffer.virt_base,
> 
> We should not have to "force" anything here.  Something feels wrong in
> the definition of these variable types...