Re: [PATCH v4] Documentation/gpu: VM_BIND locking document

Bagas Sanjaya
2023-11-16T13:14:20Z

On Wed, Nov 15, 2023 at 01:49:37PM +0100, Thomas Hellström wrote:
> +TODO: Pointer to the gpuvm code implementation if this iteration and

"... implementation of this iteration ..."

> +Using a MMU notifier for device DMA (and other methods) is described in
> +`this document
> +<https://docs.kernel.org/core-api/pin_user_pages.html#case-3-mmu-notifier-registration-with-or-without-page-faulting-hardware>`_.

You can use internal linking instead:

---- >8 ----
diff --git a/Documentation/core-api/pin_user_pages.rst b/Documentation/core-api/pin_user_pages.rst
index d3c1f6d8c0e0ec..6b5f7e6e7155fb 100644
--- a/Documentation/core-api/pin_user_pages.rst
+++ b/Documentation/core-api/pin_user_pages.rst
@@ -153,6 +153,8 @@ NOTE: Some pages, such as DAX pages, cannot be pinned with longterm pins. That's
because DAX pages do not have a separate page cache, and so "pinning" implies
locking down file system blocks, which is not (yet) supported in that way.

+.. _mmu-notifier-registration-case:
+
CASE 3: MMU notifier registration, with or without page faulting hardware
-------------------------------------------------------------------------
Device drivers can pin pages via get_user_pages*(), and register for mmu
diff --git a/Documentation/gpu/drm-vm-bind-locking.rst b/Documentation/gpu/drm-vm-bind-locking.rst
index bc701157cb3414..08b6a47a6e592f 100644
--- a/Documentation/gpu/drm-vm-bind-locking.rst
+++ b/Documentation/gpu/drm-vm-bind-locking.rst
@@ -366,8 +366,7 @@ need to care about, but so far it has proven difficult to exclude
certain notifications.

Using a MMU notifier for device DMA (and other methods) is described in
-`this document
-<https://docs.kernel.org/core-api/pin_user_pages.html#case-3-mmu-notifier-registration-with-or-without-page-faulting-hardware>`_.
+:ref:`pin_user_pages() documentation <mmu-notifier-registration-case>`.

Now the method of obtaining struct page references using
get_user_pages() unfortunately can't be used under a dma_resv lock

Thanks.

--
An old man doll... just what I always wanted! - Clara