[PATCH] misc: cxl: Change return type to vm_fault_t

[PATCH] misc: cxl: Change return type to vm_fault_t

[Souptick Joarder]

Use new return type vm_fault_t for fault handler. For
now, this is just documenting that the function returns
a VM_FAULT value rather than an errno. Once all instances
are converted, vm_fault_t will become a distinct type.

Reference id -> 1c8f422059ae ("mm: change return type to
vm_fault_t")

previously cxl_mmap_fault returns VM_FAULT_NOPAGE as
default value irrespective of vm_insert_pfn() return
value. This bug is fixed with new vmf_insert_pfn()
which will return VM_FAULT_ type based on err.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
---
 drivers/misc/cxl/context.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index 7ff315a..c6ec872 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -128,11 +128,12 @@ void cxl_context_set_mapping(struct cxl_context *ctx,
 	mutex_unlock(&ctx->mapping_lock);
 }

-static int cxl_mmap_fault(struct vm_fault *vmf)
+static vm_fault_t cxl_mmap_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct cxl_context *ctx = vma->vm_file->private_data;
 	u64 area, offset;
+	vm_fault_t ret;

 	offset = vmf->pgoff << PAGE_SHIFT;

@@ -169,11 +170,11 @@ static int cxl_mmap_fault(struct vm_fault *vmf)
 		return VM_FAULT_SIGBUS;
 	}

-	vm_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);
+	ret = vmf_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);

 	mutex_unlock(&ctx->status_mutex);

-	return VM_FAULT_NOPAGE;
+	return ret;
 }

 static const struct vm_operations_struct cxl_mmap_vmops = {
--
1.9.1

Re: [PATCH] misc: cxl: Change return type to vm_fault_t

[Andrew Donnellan]

On 18/04/18 00:53, Souptick Joarder wrote:
> Use new return type vm_fault_t for fault handler. For
> now, this is just documenting that the function returns
> a VM_FAULT value rather than an errno. Once all instances
> are converted, vm_fault_t will become a distinct type.
> 
> Reference id -> 1c8f422059ae ("mm: change return type to
> vm_fault_t")
> 
> previously cxl_mmap_fault returns VM_FAULT_NOPAGE as
> default value irrespective of vm_insert_pfn() return
> value. This bug is fixed with new vmf_insert_pfn()
> which will return VM_FAULT_ type based on err.
> 
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>

This looks good to me

Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com  IBM Australia Limited

Re: [PATCH] misc: cxl: Change return type to vm_fault_t

[Frederic Barrat]

Le 17/04/2018 à 16:53, Souptick Joarder a écrit :
> Use new return type vm_fault_t for fault handler. For
> now, this is just documenting that the function returns
> a VM_FAULT value rather than an errno. Once all instances
> are converted, vm_fault_t will become a distinct type.
> 
> Reference id -> 1c8f422059ae ("mm: change return type to
> vm_fault_t")
> 
> previously cxl_mmap_fault returns VM_FAULT_NOPAGE as
> default value irrespective of vm_insert_pfn() return
> value. This bug is fixed with new vmf_insert_pfn()
> which will return VM_FAULT_ type based on err.
> 
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> ---

It looks ok, and it passed some basic testing.

Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>

   Fred


>   drivers/misc/cxl/context.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
> index 7ff315a..c6ec872 100644
> --- a/drivers/misc/cxl/context.c
> +++ b/drivers/misc/cxl/context.c
> @@ -128,11 +128,12 @@ void cxl_context_set_mapping(struct cxl_context *ctx,
>   	mutex_unlock(&ctx->mapping_lock);
>   }
> 
> -static int cxl_mmap_fault(struct vm_fault *vmf)
> +static vm_fault_t cxl_mmap_fault(struct vm_fault *vmf)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
>   	struct cxl_context *ctx = vma->vm_file->private_data;
>   	u64 area, offset;
> +	vm_fault_t ret;
> 
>   	offset = vmf->pgoff << PAGE_SHIFT;
> 
> @@ -169,11 +170,11 @@ static int cxl_mmap_fault(struct vm_fault *vmf)
>   		return VM_FAULT_SIGBUS;
>   	}
> 
> -	vm_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);
> +	ret = vmf_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);
> 
>   	mutex_unlock(&ctx->status_mutex);
> 
> -	return VM_FAULT_NOPAGE;
> +	return ret;
>   }
> 
>   static const struct vm_operations_struct cxl_mmap_vmops = {
> --
> 1.9.1
>