+ mm-gup-fail-get_user_pages-for-longterm-dev-coherent-type.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/gup: fail get_user_pages for LONGTERM dev coherent type
has been added to the -mm tree.  Its filename is
     mm-gup-fail-get_user_pages-for-longterm-dev-coherent-type.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-gup-fail-get_user_pages-for-longterm-dev-coherent-type.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-gup-fail-get_user_pages-for-longterm-dev-coherent-type.patch

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------------------------------------------------------
From: Alex Sierra <alex.sierra@amd.com>
Subject: mm/gup: fail get_user_pages for LONGTERM dev coherent type

Avoid long term pinning for Coherent device type pages.  This could
interfere with their own device memory manager.  For now, we are just
returning error for PIN_LONGTERM Coherent device type pages.  Eventually,
these type of pages will get migrated to system memory, once the device
migration pages support is added.

Link: https://lkml.kernel.org/r/20220201154901.7921-4-alex.sierra@amd.com
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/gup.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/mm/gup.c~mm-gup-fail-get_user_pages-for-longterm-dev-coherent-type
+++ a/mm/gup.c
@@ -1870,6 +1870,12 @@ static long check_and_migrate_movable_pa
 		 * If we get a movable page, since we are going to be pinning
 		 * these entries, try to move them out if possible.
 		 */
+		if (is_dev_private_or_coherent_page(head)) {
+			WARN_ON_ONCE(is_device_private_page(head));
+			ret = -EFAULT;
+			goto unpin_pages;
+		}
+
 		if (!is_pinnable_page(head)) {
 			if (PageHuge(head)) {
 				if (!isolate_huge_page(head, &movable_page_list))
@@ -1900,6 +1906,7 @@ static long check_and_migrate_movable_pa
 	if (list_empty(&movable_page_list) && !isolation_error_count)
 		return nr_pages;
 
+unpin_pages:
 	if (gup_flags & FOLL_PIN) {
 		unpin_user_pages(pages, nr_pages);
 	} else {
_

Patches currently in -mm which might be from alex.sierra@amd.com are

mm-add-zone-device-coherent-type-memory-support.patch
mm-add-device-coherent-vma-selection-for-memory-migration.patch
mm-gup-fail-get_user_pages-for-longterm-dev-coherent-type.patch
drm-amdkfd-add-spm-support-for-svm.patch
drm-amdkfd-coherent-type-as-sys-mem-on-migration-to-ram.patch
lib-test_hmm-add-ioctl-to-get-zone-device-type.patch
lib-test_hmm-add-module-param-for-zone-device-type.patch
lib-add-support-for-device-coherent-type-in-test_hmm.patch
tools-update-hmm-test-to-support-device-coherent-type.patch
tools-update-test_hmm-script-to-support-sp-config.patch