[merged mm-stable] drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults.patch removed from -mm tree

The quilt patch titled
     Subject: drm/gpusvm: use hmm_range_fault_unlocked_timeout() for range faults
has been removed from the -mm tree.  Its filename was
     drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Stanislav Kinsburskii <[email protected]>
Subject: drm/gpusvm: use hmm_range_fault_unlocked_timeout() for range faults
Date: Thu, 23 Jul 2026 10:36:40 -0700

Several GPU SVM paths take mmap_read_lock() only to call hmm_range_fault()
and open-code mmu interval sequence setup before each HMM walk.  They also
retry -EBUSY until HMM_RANGE_DEFAULT_TIMEOUT expires.

Use hmm_range_fault_unlocked_timeout() for those faults.  The HMM helper
now owns mmap_lock acquisition and refreshes range->notifier_seq for its
internal retries, while GPU SVM keeps its existing driver-lock validation
with mmu_interval_read_retry() after a successful fault.

drm_gpusvm_scan_mm() and drm_gpusvm_range_evict() pass
HMM_RANGE_DEFAULT_TIMEOUT as the helper retry budget for each HMM fault
attempt.  drm_gpusvm_get_pages() keeps its existing absolute outer
deadline because it can be reached from GPU page-fault workers, where
fatal signals from the faulting process cannot stop an endless
invalidation retry loop.  It passes the remaining time from that deadline
to HMM for each fault attempt.

Leave drm_gpusvm_check_pages() on hmm_range_fault() because that path is
called with the mmap lock already held by its caller.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Stanislav Kinsburskii <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Dexuan Cui <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: K. Y. Srinivasan <[email protected]>
Cc: Leon Romanovsky <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lizhi Hou <[email protected]>
Cc: Long Li <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Lyude <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Oded Gabbay <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Thomas Zimemrmann <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Wei Liu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 drivers/gpu/drm/drm_gpusvm.c |   60 +++++----------------------------
 1 file changed, 10 insertions(+), 50 deletions(-)

--- a/drivers/gpu/drm/drm_gpusvm.c~drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults
+++ a/drivers/gpu/drm/drm_gpusvm.c
@@ -773,8 +773,7 @@ enum drm_gpusvm_scan_result drm_gpusvm_s
 		.end = end,
 		.dev_private_owner = dev_private_owner,
 	};
-	unsigned long timeout =
-		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	unsigned long timeout = msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 	enum drm_gpusvm_scan_result state = DRM_GPUSVM_SCAN_UNPOPULATED, new_state;
 	unsigned long *pfns;
 	unsigned long npages = npages_in_range(start, end);
@@ -788,22 +787,7 @@ enum drm_gpusvm_scan_result drm_gpusvm_s
 	hmm_range.hmm_pfns = pfns;
 
 retry:
-	hmm_range.notifier_seq = mmu_interval_read_begin(notifier);
-	mmap_read_lock(range->gpusvm->mm);
-
-	while (true) {
-		err = hmm_range_fault(&hmm_range);
-		if (err == -EBUSY) {
-			if (time_after(jiffies, timeout))
-				break;
-
-			hmm_range.notifier_seq =
-				mmu_interval_read_begin(notifier);
-			continue;
-		}
-		break;
-	}
-	mmap_read_unlock(range->gpusvm->mm);
+	err = hmm_range_fault_unlocked_timeout(&hmm_range, timeout);
 	if (err)
 		goto err_free;
 
@@ -1423,6 +1407,7 @@ int drm_gpusvm_get_pages(struct drm_gpus
 	void *zdd;
 	unsigned long timeout =
 		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	unsigned long remaining;
 	unsigned long i, j;
 	unsigned long npages = npages_in_range(pages_start, pages_end);
 	unsigned long num_dma_mapped;
@@ -1437,7 +1422,9 @@ int drm_gpusvm_get_pages(struct drm_gpus
 	struct dma_iova_state *state = &svm_pages->state;
 
 retry:
-	if (time_after(jiffies, timeout))
+	remaining = timeout - jiffies;
+
+	if (time_after_eq(jiffies, timeout))
 		return -EBUSY;
 
 	hmm_range.notifier_seq = mmu_interval_read_begin(notifier);
@@ -1454,21 +1441,7 @@ retry:
 	}
 
 	hmm_range.hmm_pfns = pfns;
-	while (true) {
-		mmap_read_lock(mm);
-		err = hmm_range_fault(&hmm_range);
-		mmap_read_unlock(mm);
-
-		if (err == -EBUSY) {
-			if (time_after(jiffies, timeout))
-				break;
-
-			hmm_range.notifier_seq =
-				mmu_interval_read_begin(notifier);
-			continue;
-		}
-		break;
-	}
+	err = hmm_range_fault_unlocked_timeout(&hmm_range, remaining);
 	mmput(mm);
 	if (err)
 		goto err_free;
@@ -1741,8 +1714,7 @@ int drm_gpusvm_range_evict(struct drm_gp
 		.end = drm_gpusvm_range_end(range),
 		.dev_private_owner = NULL,
 	};
-	unsigned long timeout =
-		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	unsigned long timeout = msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 	unsigned long *pfns;
 	unsigned long npages = npages_in_range(drm_gpusvm_range_start(range),
 					       drm_gpusvm_range_end(range));
@@ -1759,24 +1731,12 @@ int drm_gpusvm_range_evict(struct drm_gp
 	}
 
 	hmm_range.hmm_pfns = pfns;
-	while (!time_after(jiffies, timeout)) {
-		hmm_range.notifier_seq = mmu_interval_read_begin(notifier);
-		if (time_after(jiffies, timeout)) {
-			err = -ETIME;
-			break;
-		}
-
-		mmap_read_lock(mm);
-		err = hmm_range_fault(&hmm_range);
-		mmap_read_unlock(mm);
-		if (err != -EBUSY)
-			break;
-	}
+	err = hmm_range_fault_unlocked_timeout(&hmm_range, timeout);
 
 	kvfree(pfns);
 	mmput(mm);
 
-	return err;
+	return err == -EBUSY ? -ETIME : err;
 }
 EXPORT_SYMBOL_GPL(drm_gpusvm_range_evict);
 
_

Patches currently in -mm which might be from [email protected] are