int retval = VM_FAULT_NOPAGE;
struct ttm_mem_type_manager *man =
&bdev->man[bo->mem.mem_type];
+ struct vm_area_struct cvma;
/*
* Work around locking order reversal in fault / nopfn
* between mmap_sem and bo_reserve: Perform a trylock operation
- * for reserve, and if it fails, retry the fault after scheduling.
+ * for reserve, and if it fails, retry the fault after waiting
+ * for the buffer to become unreserved.
*/
-
- ret = ttm_bo_reserve(bo, true, true, false, 0);
+ ret = ttm_bo_reserve(bo, true, true, false, NULL);
if (unlikely(ret != 0)) {
- if (ret == -EBUSY)
- set_need_resched();
+ if (ret != -EBUSY)
+ return VM_FAULT_NOPAGE;
+
+ if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
+ up_read(&vma->vm_mm->mmap_sem);
+ (void) ttm_bo_wait_unreserved(bo);
+ }
+
+ return VM_FAULT_RETRY;
+ }
+
+ /*
+ * If we'd want to change locking order to
+ * mmap_sem -> bo::reserve, we'd use a blocking reserve here
+ * instead of retrying the fault...
+ */
return VM_FAULT_NOPAGE;
}
case 0:
break;
case -EBUSY:
- set_need_resched();
case -ERESTARTSYS:
retval = VM_FAULT_NOPAGE;
goto out_unlock;
}
/*
- * Strictly, we're not allowed to modify vma->vm_page_prot here,
- * since the mmap_sem is only held in read mode. However, we
- * modify only the caching bits of vma->vm_page_prot and
- * consider those bits protected by
- * the bo->mutex, as we should be the only writers.
- * There shouldn't really be any readers of these bits except
- * within vm_insert_mixed()? fork?
- *
- * TODO: Add a list of vmas to the bo, and change the
- * vma->vm_page_prot when the object changes caching policy, with
- * the correct locks held.
+ * Make a local vma copy to modify the page_prot member
+ * and vm_flags if necessary. The vma parameter is protected
+ * by mmap_sem in write mode.
*/
+ cvma = *vma;
+ cvma.vm_page_prot = vm_get_page_prot(cvma.vm_flags);
+
if (bo->mem.bus.is_iomem) {
- vma->vm_page_prot = ttm_io_prot(bo->mem.placement,
- vma->vm_page_prot);
+ cvma.vm_page_prot = ttm_io_prot(bo->mem.placement,
+ cvma.vm_page_prot);
} else {
ttm = bo->ttm;
- vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ?
- vm_get_page_prot(vma->vm_flags) :
- ttm_io_prot(bo->mem.placement, vma->vm_page_prot);
+ if (!(bo->mem.placement & TTM_PL_FLAG_CACHED))
+ cvma.vm_page_prot = ttm_io_prot(bo->mem.placement,
+ cvma.vm_page_prot);
/* Allocate all page at once, most common usage */
if (ttm->bdev->driver->ttm_tt_populate(ttm)) {
pfn = page_to_pfn(page);
}
- ret = vm_insert_mixed(vma, address, pfn);
+ ret = vm_insert_mixed(&cvma, address, pfn);
/*
* Somebody beat us to this PTE or prefaulting to
* an already populated PTE, or prefaulting error.