Messages in this thread | | | Subject | Re: [PATCH v2] gpu: drm: ttm: Adding new return type vm_fault_t | From | Christian König <> | Date | Fri, 8 Jun 2018 08:44:06 +0200 |
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Am 08.06.2018 um 06:36 schrieb Souptick Joarder: > On Sat, Jun 2, 2018 at 12:57 AM, Souptick Joarder <jrdr.linux@gmail.com> 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") >> >> Previously vm_insert_{mixed,pfn} returns err which driver >> mapped into VM_FAULT_* type. The new function >> vmf_insert_{mixed,pfn} will replace this inefficiency by >> returning VM_FAULT_* type. >> >> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> >> --- >> v2: Address christian's comment. Put reverse >> xmas tree order for variable declarations. >> >> drivers/gpu/drm/ttm/ttm_bo_vm.c | 45 ++++++++++++++++++++--------------------- >> 1 file changed, 22 insertions(+), 23 deletions(-) >> >> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c >> index 8eba95b..9de8b4f 100644 >> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c >> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c >> @@ -43,10 +43,11 @@ >> >> #define TTM_BO_VM_NUM_PREFAULT 16 >> >> -static int ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, >> +static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, >> struct vm_fault *vmf) >> { >> - int ret = 0; >> + vm_fault_t ret = 0; >> + int err = 0; >> >> if (likely(!bo->moving)) >> goto out_unlock; >> @@ -77,9 +78,9 @@ static int ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, >> /* >> * Ordinary wait. >> */ >> - ret = dma_fence_wait(bo->moving, true); >> - if (unlikely(ret != 0)) { >> - ret = (ret != -ERESTARTSYS) ? VM_FAULT_SIGBUS : >> + err = dma_fence_wait(bo->moving, true); >> + if (unlikely(err != 0)) { >> + ret = (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS : >> VM_FAULT_NOPAGE; >> goto out_unlock; >> } >> @@ -104,7 +105,7 @@ static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo, >> + page_offset; >> } >> >> -static int ttm_bo_vm_fault(struct vm_fault *vmf) >> +static vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) >> { >> struct vm_area_struct *vma = vmf->vma; >> struct ttm_buffer_object *bo = (struct ttm_buffer_object *) >> @@ -115,8 +116,9 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) >> unsigned long pfn; >> struct ttm_tt *ttm = NULL; >> struct page *page; >> - int ret; >> + int err; >> int i; >> + vm_fault_t ret = VM_FAULT_NOPAGE; >> unsigned long address = vmf->address; >> struct ttm_mem_type_manager *man = >> &bdev->man[bo->mem.mem_type]; >> @@ -128,9 +130,9 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) >> * for reserve, and if it fails, retry the fault after waiting >> * for the buffer to become unreserved. >> */ >> - ret = ttm_bo_reserve(bo, true, true, NULL); >> - if (unlikely(ret != 0)) { >> - if (ret != -EBUSY) >> + err = ttm_bo_reserve(bo, true, true, NULL); >> + if (unlikely(err != 0)) { >> + if (err != -EBUSY) >> return VM_FAULT_NOPAGE; >> >> if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) { >> @@ -162,8 +164,8 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) >> } >> >> if (bdev->driver->fault_reserve_notify) { >> - ret = bdev->driver->fault_reserve_notify(bo); >> - switch (ret) { >> + err = bdev->driver->fault_reserve_notify(bo); >> + switch (err) { >> case 0: >> break; >> case -EBUSY: >> @@ -191,13 +193,13 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) >> goto out_unlock; >> } >> >> - ret = ttm_mem_io_lock(man, true); >> - if (unlikely(ret != 0)) { >> + err = ttm_mem_io_lock(man, true); >> + if (unlikely(err != 0)) { >> ret = VM_FAULT_NOPAGE; >> goto out_unlock; >> } >> - ret = ttm_mem_io_reserve_vm(bo); >> - if (unlikely(ret != 0)) { >> + err = ttm_mem_io_reserve_vm(bo); >> + if (unlikely(err != 0)) { >> ret = VM_FAULT_SIGBUS; >> goto out_io_unlock; >> } >> @@ -265,23 +267,20 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) >> } >> >> if (vma->vm_flags & VM_MIXEDMAP) >> - ret = vm_insert_mixed(&cvma, address, >> + ret = vmf_insert_mixed(&cvma, address, >> __pfn_to_pfn_t(pfn, PFN_DEV)); >> else >> - ret = vm_insert_pfn(&cvma, address, pfn); >> + ret = vmf_insert_pfn(&cvma, address, pfn); >> >> /* >> * Somebody beat us to this PTE or prefaulting to >> * an already populated PTE, or prefaulting error. >> */ >> >> - if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0))) >> + if (unlikely((ret == VM_FAULT_NOPAGE && i > 0))) >> break; >> - else if (unlikely(ret != 0)) { >> - ret = >> - (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS; >> + else if (unlikely(ret & VM_FAULT_ERROR)) >> goto out_io_unlock; >> - } >> >> address += PAGE_SIZE; >> if (unlikely(++page_offset >= page_last)) >> -- >> 1.9.1 >> > If no further comment, we would like get this patch in 4.18 / 4.18-rc-x. The patch looks good to me and I will pick it up for the next TTM pull request. I don't think it will make it into 4.18-rc-1, but 4.18-rc-x sounds realistic.
Christian.
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