diff options
| author |   David Hildenbrand <david@redhat.com> | 2025-02-26 14:22:57 +0100 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2025-03-17 00:05:30 -0700 |
| commit | 720ba85040a6549674e5599685ca7df86a902448 (patch) | |
| tree | 60be766b755c223ce83afa575db658b303ad79f6 | |
| parent | mm/memory: document restore_exclusive_pte() (diff) | |
| download | wireguard-linux-720ba85040a6549674e5599685ca7df86a902448.tar.xz wireguard-linux-720ba85040a6549674e5599685ca7df86a902448.zip | |
mm/mmu_notifier: use MMU_NOTIFY_CLEAR in remove_device_exclusive_entry()
Let's limit the use of MMU_NOTIFY_EXCLUSIVE to the case where we convert a
present PTE to device-exclusive. For the other case, we can simply use
MMU_NOTIFY_CLEAR, because it really is clearing the device-exclusive entry
first, to then install the present entry.
Update the documentation of MMU_NOTIFY_EXCLUSIVE, to document the single
use case more thoroughly.
If ever required, we could add a separate MMU_NOTIFY_CLEAR_EXCLUSIVE; for
now using MMU_NOTIFY_CLEAR seems to be sufficient.
Link: https://lkml.kernel.org/r/20250226132257.2826043-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/mmu_notifier.h | 8 | ||||
| -rw-r--r-- | mm/memory.c | 2 |
2 files changed, 5 insertions, 5 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index d4e714661826..bc2402a45741 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -43,10 +43,10 @@ struct mmu_interval_notifier; * a device driver to possibly ignore the invalidation if the * owner field matches the driver's device private pgmap owner. * - * @MMU_NOTIFY_EXCLUSIVE: to signal a device driver that the device will no - * longer have exclusive access to the page. When sent during creation of an - * exclusive range the owner will be initialised to the value provided by the - * caller of make_device_exclusive(), otherwise the owner will be NULL. + * @MMU_NOTIFY_EXCLUSIVE: conversion of a page table entry to device-exclusive. + * The owner is initialized to the value provided by the caller of + * make_device_exclusive(), such that this caller can filter out these + * events. */ enum mmu_notifier_event { MMU_NOTIFY_UNMAP = 0, diff --git a/mm/memory.c b/mm/memory.c index 5b475d31ce41..4c12a05fabd9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4003,7 +4003,7 @@ static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) folio_put(folio); return ret; } - mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, + mmu_notifier_range_init_owner(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, vmf->address & PAGE_MASK, (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); mmu_notifier_invalidate_range_start(&range); |