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SubjectRe: [PATCH] misc: ocxl: Change return type for fault handler
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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 = {
>

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

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