+ rdma-umem-use-hmm_range_fault_unlocked_timeout-for-odp-faults.patch added to mm-new branch

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

The patch titled
     Subject: RDMA/umem: use hmm_range_fault_unlocked_timeout() for ODP faults
has been added to the -mm mm-new branch.  Its filename is
     rdma-umem-use-hmm_range_fault_unlocked_timeout-for-odp-faults.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/rdma-umem-use-hmm_range_fault_unlocked_timeout-for-odp-faults.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Stanislav Kinsburskii <skinsburskii@gmail.com>
Subject: RDMA/umem: use hmm_range_fault_unlocked_timeout() for ODP faults
Date: Fri, 10 Jul 2026 14:27:05 -0700

ib_umem_odp_map_dma_and_lock() takes mmap_read_lock() only around
hmm_range_fault(), then retries -EBUSY until HMM_RANGE_DEFAULT_TIMEOUT
expires.

Use hmm_range_fault_unlocked_timeout() instead.  The HMM helper now owns
the mmap lock and refreshes range->notifier_seq for its internal retries. 
ODP keeps using HMM_RANGE_DEFAULT_TIMEOUT for each HMM fault attempt,
while interval invalidation retries continue to be handled by the existing
outer loop.

ODP still validates the interval notifier sequence while holding
umem_mutex before DMA mapping pages.

Link: https://lore.kernel.org/178371882559.900500.4008217424194230517.stgit@skinsburskii
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <kees@kernel.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/infiniband/core/umem_odp.c |   18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

--- a/drivers/infiniband/core/umem_odp.c~rdma-umem-use-hmm_range_fault_unlocked_timeout-for-odp-faults
+++ a/drivers/infiniband/core/umem_odp.c
@@ -329,7 +329,7 @@ int ib_umem_odp_map_dma_and_lock(struct
 	struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
 	int pfn_index, dma_index, ret = 0, start_idx;
 	unsigned int page_shift, hmm_order, pfn_start_idx;
-	unsigned long num_pfns, current_seq;
+	unsigned long num_pfns;
 	struct hmm_range range = {};
 	unsigned long timeout;
 
@@ -363,26 +363,18 @@ int ib_umem_odp_map_dma_and_lock(struct
 	}
 
 	range.hmm_pfns = &(umem_odp->map.pfn_list[pfn_start_idx]);
-	timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	timeout = msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 
 retry:
-	current_seq = range.notifier_seq =
-		mmu_interval_read_begin(&umem_odp->notifier);
-
-	mmap_read_lock(owning_mm);
-	ret = hmm_range_fault(&range);
-	mmap_read_unlock(owning_mm);
-	if (unlikely(ret)) {
-		if (ret == -EBUSY && !time_after(jiffies, timeout))
-			goto retry;
+	ret = hmm_range_fault_unlocked_timeout(&range, timeout);
+	if (unlikely(ret))
 		goto out_put_mm;
-	}
 
 	start_idx = (range.start - ib_umem_start(umem_odp)) >> page_shift;
 	dma_index = start_idx;
 
 	mutex_lock(&umem_odp->umem_mutex);
-	if (mmu_interval_read_retry(&umem_odp->notifier, current_seq)) {
+	if (mmu_interval_read_retry(&umem_odp->notifier, range.notifier_seq)) {
 		mutex_unlock(&umem_odp->umem_mutex);
 		goto retry;
 	}
_

Patches currently in -mm which might be from skinsburskii@gmail.com are

lib-test_hmm-use-device-devt-for-coherent-device-range-selection.patch
mm-hmm-move-page-fault-handling-out-of-walk-callbacks.patch
mm-hmm-add-hmm_range_fault_unlocked_timeout-for-mmap-lock-drop-support.patch
selftests-mm-add-hmm-test-for-mmap-lock-dropping-faults.patch
mshv-use-hmm_range_fault_unlocked_timeout-for-region-faults.patch
drm-nouveau-use-hmm_range_fault_unlocked_timeout-for-svm-faults.patch
rdma-umem-use-hmm_range_fault_unlocked_timeout-for-odp-faults.patch
accel-amdxdna-use-hmm_range_fault_unlocked_timeout-for-range-population.patch
drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults.patch