[PATCH] mm/hmm: replace hmm_update with mmu_notifier_range

From: Ralph Campbell <rcampbell@nvidia.com>
To: <linux-mm@kvack.org>
Cc: linux-kernel@vger.kernel.org, nouveau@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org,
	"Ralph Campbell" <rcampbell@nvidia.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Jason Gunthorpe" <jgg@mellanox.com>,
	"Christoph Hellwig" <hch@lst.de>,
	"Ben Skeggs" <bskeggs@redhat.com>
Subject: [PATCH] mm/hmm: replace hmm_update with mmu_notifier_range
Date: Tue, 23 Jul 2019 14:05:06 -0700	[thread overview]
Message-ID: <20190723210506.25127-1-rcampbell@nvidia.com> (raw)

The hmm_mirror_ops callback function sync_cpu_device_pagetables() passes
a struct hmm_update which is a simplified version of struct
mmu_notifier_range. This is unnecessary so replace hmm_update with
mmu_notifier_range directly.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Skeggs <bskeggs@redhat.com>
---

This is based on 5.3.0-rc1 plus Christoph Hellwig's 6 patches
("hmm_range_fault related fixes and legacy API removal v2").
Jason, I believe this is the patch you were requesting.

 drivers/gpu/drm/nouveau/nouveau_svm.c |  4 ++--
 include/linux/hmm.h                   | 31 ++++-----------------------
 mm/hmm.c                              | 13 ++++-------
 3 files changed, 10 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index a9c5c58d425b..6298d2dadb55 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -252,13 +252,13 @@ nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
 
 static int
 nouveau_svmm_sync_cpu_device_pagetables(struct hmm_mirror *mirror,
-					const struct hmm_update *update)
+					const struct mmu_notifier_range *update)
 {
 	struct nouveau_svmm *svmm = container_of(mirror, typeof(*svmm), mirror);
 	unsigned long start = update->start;
 	unsigned long limit = update->end;
 
-	if (!update->blockable)
+	if (!mmu_notifier_range_blockable(update))
 		return -EAGAIN;
 
 	SVMM_DBG(svmm, "invalidate %016lx-%016lx", start, limit);
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 9f32586684c9..659e25a15700 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -340,29 +340,6 @@ static inline uint64_t hmm_device_entry_from_pfn(const struct hmm_range *range,
 
 struct hmm_mirror;
 
-/*
- * enum hmm_update_event - type of update
- * @HMM_UPDATE_INVALIDATE: invalidate range (no indication as to why)
- */
-enum hmm_update_event {
-	HMM_UPDATE_INVALIDATE,
-};
-
-/*
- * struct hmm_update - HMM update information for callback
- *
- * @start: virtual start address of the range to update
- * @end: virtual end address of the range to update
- * @event: event triggering the update (what is happening)
- * @blockable: can the callback block/sleep ?
- */
-struct hmm_update {
-	unsigned long start;
-	unsigned long end;
-	enum hmm_update_event event;
-	bool blockable;
-};
-
 /*
  * struct hmm_mirror_ops - HMM mirror device operations callback
  *
@@ -383,9 +360,9 @@ struct hmm_mirror_ops {
 	/* sync_cpu_device_pagetables() - synchronize page tables
 	 *
 	 * @mirror: pointer to struct hmm_mirror
-	 * @update: update information (see struct hmm_update)
-	 * Return: -EAGAIN if update.blockable false and callback need to
-	 *          block, 0 otherwise.
+	 * @update: update information (see struct mmu_notifier_range)
+	 * Return: -EAGAIN if mmu_notifier_range_blockable(update) is false
+	 * and callback needs to block, 0 otherwise.
 	 *
 	 * This callback ultimately originates from mmu_notifiers when the CPU
 	 * page table is updated. The device driver must update its page table
@@ -397,7 +374,7 @@ struct hmm_mirror_ops {
 	 * synchronous call.
 	 */
 	int (*sync_cpu_device_pagetables)(struct hmm_mirror *mirror,
-					  const struct hmm_update *update);
+				const struct mmu_notifier_range *update);
 };
 
 /*
diff --git a/mm/hmm.c b/mm/hmm.c
index 16b6731a34db..b810a4fa3de9 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -165,7 +165,6 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
 {
 	struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
 	struct hmm_mirror *mirror;
-	struct hmm_update update;
 	struct hmm_range *range;
 	unsigned long flags;
 	int ret = 0;
@@ -173,15 +172,10 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
 	if (!kref_get_unless_zero(&hmm->kref))
 		return 0;
 
-	update.start = nrange->start;
-	update.end = nrange->end;
-	update.event = HMM_UPDATE_INVALIDATE;
-	update.blockable = mmu_notifier_range_blockable(nrange);
-
 	spin_lock_irqsave(&hmm->ranges_lock, flags);
 	hmm->notifiers++;
 	list_for_each_entry(range, &hmm->ranges, list) {
-		if (update.end < range->start || update.start >= range->end)
+		if (nrange->end < range->start || nrange->start >= range->end)
 			continue;
 
 		range->valid = false;
@@ -198,9 +192,10 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
 	list_for_each_entry(mirror, &hmm->mirrors, list) {
 		int rc;
 
-		rc = mirror->ops->sync_cpu_device_pagetables(mirror, &update);
+		rc = mirror->ops->sync_cpu_device_pagetables(mirror, nrange);
 		if (rc) {
-			if (WARN_ON(update.blockable || rc != -EAGAIN))
+			if (WARN_ON(mmu_notifier_range_blockable(nrange) ||
+			    rc != -EAGAIN))
 				continue;
 			ret = -EAGAIN;
 			break;
-- 
2.20.1

