misc: ocxl: Change return type for fault handler

Message ID 20180611202904.GA25538@jordon-HP-15-Notebook-PC
State Accepted
Commit a545cf032d11437ed86e62f00d499108d91cae54
Headers show
Series
  • misc: ocxl: Change return type for fault handler
Related show

Commit Message

Souptick Joarder June 11, 2018, 8:29 p.m.
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.

Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")

There is an existing bug when vm_insert_pfn() can return
ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
default. The new inline vmf_insert_pfn() has removed
this inefficiency by returning correct vm_fault_ type.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
---
 drivers/misc/ocxl/context.c | 22 +++++++++++-----------
 drivers/misc/ocxl/sysfs.c   |  5 ++---
 2 files changed, 13 insertions(+), 14 deletions(-)

Comments

Andrew Donnellan June 12, 2018, 4:39 a.m. | #1
On 12/06/18 06:29, 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.
> 
> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
> 
> There is an existing bug when vm_insert_pfn() can return
> ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
> default. The new inline vmf_insert_pfn() has removed
> this inefficiency by returning correct vm_fault_ type.
> 
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>

Looks okay to me

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

> ---
>   drivers/misc/ocxl/context.c | 22 +++++++++++-----------
>   drivers/misc/ocxl/sysfs.c   |  5 ++---
>   2 files changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
> index 909e880..98daf91 100644
> --- a/drivers/misc/ocxl/context.c
> +++ b/drivers/misc/ocxl/context.c
> @@ -83,7 +83,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
>   	return rc;
>   }
>   
> -static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
> +static vm_fault_t map_afu_irq(struct vm_area_struct *vma, unsigned long address,
>   		u64 offset, struct ocxl_context *ctx)
>   {
>   	u64 trigger_addr;
> @@ -92,15 +92,15 @@ static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
>   	if (!trigger_addr)
>   		return VM_FAULT_SIGBUS;
>   
> -	vm_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
> -	return VM_FAULT_NOPAGE;
> +	return vmf_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
>   }
>   
> -static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
> +static vm_fault_t map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
>   		u64 offset, struct ocxl_context *ctx)
>   {
>   	u64 pp_mmio_addr;
>   	int pasid_off;
> +	vm_fault_t ret;
>   
>   	if (offset >= ctx->afu->config.pp_mmio_stride)
>   		return VM_FAULT_SIGBUS;
> @@ -118,27 +118,27 @@ static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
>   		pasid_off * ctx->afu->config.pp_mmio_stride +
>   		offset;
>   
> -	vm_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
> +	ret = vmf_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
>   	mutex_unlock(&ctx->status_mutex);
> -	return VM_FAULT_NOPAGE;
> +	return ret;
>   }
>   
> -static int ocxl_mmap_fault(struct vm_fault *vmf)
> +static vm_fault_t ocxl_mmap_fault(struct vm_fault *vmf)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
>   	struct ocxl_context *ctx = vma->vm_file->private_data;
>   	u64 offset;
> -	int rc;
> +	vm_fault_t ret;
>   
>   	offset = vmf->pgoff << PAGE_SHIFT;
>   	pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
>   		ctx->pasid, vmf->address, offset);
>   
>   	if (offset < ctx->afu->irq_base_offset)
> -		rc = map_pp_mmio(vma, vmf->address, offset, ctx);
> +		ret = map_pp_mmio(vma, vmf->address, offset, ctx);
>   	else
> -		rc = map_afu_irq(vma, vmf->address, offset, ctx);
> -	return rc;
> +		ret = map_afu_irq(vma, vmf->address, offset, ctx);
> +	return ret;
>   }
>   
>   static const struct vm_operations_struct ocxl_vmops = {
> diff --git a/drivers/misc/ocxl/sysfs.c b/drivers/misc/ocxl/sysfs.c
> index d9753a1..0ab1fd1 100644
> --- a/drivers/misc/ocxl/sysfs.c
> +++ b/drivers/misc/ocxl/sysfs.c
> @@ -64,7 +64,7 @@ static ssize_t global_mmio_read(struct file *filp, struct kobject *kobj,
>   	return count;
>   }
>   
> -static int global_mmio_fault(struct vm_fault *vmf)
> +static vm_fault_t global_mmio_fault(struct vm_fault *vmf)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
>   	struct ocxl_afu *afu = vma->vm_private_data;
> @@ -75,8 +75,7 @@ static int global_mmio_fault(struct vm_fault *vmf)
>   
>   	offset = vmf->pgoff;
>   	offset += (afu->global_mmio_start >> PAGE_SHIFT);
> -	vm_insert_pfn(vma, vmf->address, offset);
> -	return VM_FAULT_NOPAGE;
> +	return vmf_insert_pfn(vma, vmf->address, offset);
>   }
>   
>   static const struct vm_operations_struct global_mmio_vmops = {
>
Frederic Barrat June 14, 2018, 4:06 p.m. | #2
Le 11/06/2018 à 22:29, 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.
> 
> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
> 
> There is an existing bug when vm_insert_pfn() can return
> ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
> default. The new inline vmf_insert_pfn() has removed
> this inefficiency by returning correct vm_fault_ type.
> 
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> ---

Thanks!

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


>   drivers/misc/ocxl/context.c | 22 +++++++++++-----------
>   drivers/misc/ocxl/sysfs.c   |  5 ++---
>   2 files changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
> index 909e880..98daf91 100644
> --- a/drivers/misc/ocxl/context.c
> +++ b/drivers/misc/ocxl/context.c
> @@ -83,7 +83,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
>   	return rc;
>   }
> 
> -static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
> +static vm_fault_t map_afu_irq(struct vm_area_struct *vma, unsigned long address,
>   		u64 offset, struct ocxl_context *ctx)
>   {
>   	u64 trigger_addr;
> @@ -92,15 +92,15 @@ static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
>   	if (!trigger_addr)
>   		return VM_FAULT_SIGBUS;
> 
> -	vm_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
> -	return VM_FAULT_NOPAGE;
> +	return vmf_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
>   }
> 
> -static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
> +static vm_fault_t map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
>   		u64 offset, struct ocxl_context *ctx)
>   {
>   	u64 pp_mmio_addr;
>   	int pasid_off;
> +	vm_fault_t ret;
> 
>   	if (offset >= ctx->afu->config.pp_mmio_stride)
>   		return VM_FAULT_SIGBUS;
> @@ -118,27 +118,27 @@ static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
>   		pasid_off * ctx->afu->config.pp_mmio_stride +
>   		offset;
> 
> -	vm_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
> +	ret = vmf_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
>   	mutex_unlock(&ctx->status_mutex);
> -	return VM_FAULT_NOPAGE;
> +	return ret;
>   }
> 
> -static int ocxl_mmap_fault(struct vm_fault *vmf)
> +static vm_fault_t ocxl_mmap_fault(struct vm_fault *vmf)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
>   	struct ocxl_context *ctx = vma->vm_file->private_data;
>   	u64 offset;
> -	int rc;
> +	vm_fault_t ret;
> 
>   	offset = vmf->pgoff << PAGE_SHIFT;
>   	pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
>   		ctx->pasid, vmf->address, offset);
> 
>   	if (offset < ctx->afu->irq_base_offset)
> -		rc = map_pp_mmio(vma, vmf->address, offset, ctx);
> +		ret = map_pp_mmio(vma, vmf->address, offset, ctx);
>   	else
> -		rc = map_afu_irq(vma, vmf->address, offset, ctx);
> -	return rc;
> +		ret = map_afu_irq(vma, vmf->address, offset, ctx);
> +	return ret;
>   }
> 
>   static const struct vm_operations_struct ocxl_vmops = {
> diff --git a/drivers/misc/ocxl/sysfs.c b/drivers/misc/ocxl/sysfs.c
> index d9753a1..0ab1fd1 100644
> --- a/drivers/misc/ocxl/sysfs.c
> +++ b/drivers/misc/ocxl/sysfs.c
> @@ -64,7 +64,7 @@ static ssize_t global_mmio_read(struct file *filp, struct kobject *kobj,
>   	return count;
>   }
> 
> -static int global_mmio_fault(struct vm_fault *vmf)
> +static vm_fault_t global_mmio_fault(struct vm_fault *vmf)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
>   	struct ocxl_afu *afu = vma->vm_private_data;
> @@ -75,8 +75,7 @@ static int global_mmio_fault(struct vm_fault *vmf)
> 
>   	offset = vmf->pgoff;
>   	offset += (afu->global_mmio_start >> PAGE_SHIFT);
> -	vm_insert_pfn(vma, vmf->address, offset);
> -	return VM_FAULT_NOPAGE;
> +	return vmf_insert_pfn(vma, vmf->address, offset);
>   }
> 
>   static const struct vm_operations_struct global_mmio_vmops = {
>
Souptick Joarder June 19, 2018, 5:09 a.m. | #3
On Thu, Jun 14, 2018 at 9:36 PM, Frederic Barrat <fbarrat@linux.ibm.com> wrote:
>
>
> Le 11/06/2018 à 22:29, 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.
>>
>> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>>
>> There is an existing bug when vm_insert_pfn() can return
>> ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
>> default. The new inline vmf_insert_pfn() has removed
>> this inefficiency by returning correct vm_fault_ type.
>>
>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> ---
>
>
> Thanks!
>
> Tested and
> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
>
>

Frederic, is this patch queued for 4.19 ?
Michael Ellerman June 19, 2018, 12:57 p.m. | #4
Souptick Joarder <jrdr.linux@gmail.com> writes:
> On Thu, Jun 14, 2018 at 9:36 PM, Frederic Barrat <fbarrat@linux.ibm.com> wrote:
>> Le 11/06/2018 à 22:29, 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.
>>>
>>> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>>>
>>> There is an existing bug when vm_insert_pfn() can return
>>> ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
>>> default. The new inline vmf_insert_pfn() has removed
>>> this inefficiency by returning correct vm_fault_ type.
>>>
>>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>>> ---
>>
>>
>> Thanks!
>>
>> Tested and
>> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
>
> Frederic, is this patch queued for 4.19 ?

Not yet, you're a bit early. 4.18-rc1 only came out the other day :)

Your patches are tracked here:

  http://patchwork.ozlabs.org/project/linuxppc-dev/list/?submitter=67924


They should appear in 4.19 unless something conflicts with them.

cheers
Michael Ellerman July 11, 2018, 1:24 p.m. | #5
On Mon, 2018-06-11 at 20:29:04 UTC, 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.
> 
> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
> 
> There is an existing bug when vm_insert_pfn() can return
> ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
> default. The new inline vmf_insert_pfn() has removed
> this inefficiency by returning correct vm_fault_ type.
> 
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/a545cf032d11437ed86e62f00d4991

cheers
Souptick Joarder July 13, 2018, 12:57 p.m. | #6
On Wed, Jul 11, 2018 at 6:54 PM, Michael Ellerman
<patch-notifications@ellerman.id.au> wrote:
> On Mon, 2018-06-11 at 20:29:04 UTC, 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.
>>
>> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>>
>> There is an existing bug when vm_insert_pfn() can return
>> ENOMEM which was ignored and VM_FAULT_NOPAGE returned as
>> default. The new inline vmf_insert_pfn() has removed
>> this inefficiency by returning correct vm_fault_ type.
>>
>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
>> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
>
> Applied to powerpc next, thanks.
>
> https://git.kernel.org/powerpc/c/a545cf032d11437ed86e62f00d4991
>
> cheers

Thanks :)

Patch

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e880..98daf91 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -83,7 +83,7 @@  int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 	return rc;
 }
 
-static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
+static vm_fault_t map_afu_irq(struct vm_area_struct *vma, unsigned long address,
 		u64 offset, struct ocxl_context *ctx)
 {
 	u64 trigger_addr;
@@ -92,15 +92,15 @@  static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
 	if (!trigger_addr)
 		return VM_FAULT_SIGBUS;
 
-	vm_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
-	return VM_FAULT_NOPAGE;
+	return vmf_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
 }
 
-static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
+static vm_fault_t map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
 		u64 offset, struct ocxl_context *ctx)
 {
 	u64 pp_mmio_addr;
 	int pasid_off;
+	vm_fault_t ret;
 
 	if (offset >= ctx->afu->config.pp_mmio_stride)
 		return VM_FAULT_SIGBUS;
@@ -118,27 +118,27 @@  static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
 		pasid_off * ctx->afu->config.pp_mmio_stride +
 		offset;
 
-	vm_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
+	ret = vmf_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
 	mutex_unlock(&ctx->status_mutex);
-	return VM_FAULT_NOPAGE;
+	return ret;
 }
 
-static int ocxl_mmap_fault(struct vm_fault *vmf)
+static vm_fault_t ocxl_mmap_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct ocxl_context *ctx = vma->vm_file->private_data;
 	u64 offset;
-	int rc;
+	vm_fault_t ret;
 
 	offset = vmf->pgoff << PAGE_SHIFT;
 	pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
 		ctx->pasid, vmf->address, offset);
 
 	if (offset < ctx->afu->irq_base_offset)
-		rc = map_pp_mmio(vma, vmf->address, offset, ctx);
+		ret = map_pp_mmio(vma, vmf->address, offset, ctx);
 	else
-		rc = map_afu_irq(vma, vmf->address, offset, ctx);
-	return rc;
+		ret = map_afu_irq(vma, vmf->address, offset, ctx);
+	return ret;
 }
 
 static const struct vm_operations_struct ocxl_vmops = {
diff --git a/drivers/misc/ocxl/sysfs.c b/drivers/misc/ocxl/sysfs.c
index d9753a1..0ab1fd1 100644
--- a/drivers/misc/ocxl/sysfs.c
+++ b/drivers/misc/ocxl/sysfs.c
@@ -64,7 +64,7 @@  static ssize_t global_mmio_read(struct file *filp, struct kobject *kobj,
 	return count;
 }
 
-static int global_mmio_fault(struct vm_fault *vmf)
+static vm_fault_t global_mmio_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct ocxl_afu *afu = vma->vm_private_data;
@@ -75,8 +75,7 @@  static int global_mmio_fault(struct vm_fault *vmf)
 
 	offset = vmf->pgoff;
 	offset += (afu->global_mmio_start >> PAGE_SHIFT);
-	vm_insert_pfn(vma, vmf->address, offset);
-	return VM_FAULT_NOPAGE;
+	return vmf_insert_pfn(vma, vmf->address, offset);
 }
 
 static const struct vm_operations_struct global_mmio_vmops = {