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From:   David Hildenbrand <david@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-mm@kvack.org, virtualization@lists.linux-foundation.org,
        Andrew Morton <akpm@linux-foundation.org>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Subject: [PATCH v1 17/29] virito-mem: subblock states are specific to Sub Block Mode (SBM)
Date:   Mon, 12 Oct 2020 14:53:11 +0200
Message-Id: <20201012125323.17509-18-david@redhat.com>
In-Reply-To: <20201012125323.17509-1-david@redhat.com>
References: <20201012125323.17509-1-david@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Let's rename and move accordingly. While at it, rename sb_bitmap to
"sb_states".

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/virtio/virtio_mem.c | 118 +++++++++++++++++++-----------------
 1 file changed, 62 insertions(+), 56 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index e76d6f769aa5..2cc497ad8298 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -137,17 +137,23 @@ struct virtio_mem {
 		 * memory in one 4 KiB page.
 		 */
 		uint8_t *mb_states;
-	} sbm;
 
-	/*
-	 * $nb_sb_per_mb bit per memory block. Handled similar to sbm.mb_states.
-	 *
-	 * With 4MB subblocks, we manage 128GB of memory in one page.
-	 */
-	unsigned long *sb_bitmap;
+		/*
+		 * Bitmap: one bit per subblock. Allocated similar to
+		 * sbm.mb_states.
+		 *
+		 * A set bit means the corresponding subblock is plugged,
+		 * otherwise it's unblocked.
+		 *
+		 * With 4 MiB subblocks, we manage 128 GiB of memory in one
+		 * 4 KiB page.
+		 */
+		unsigned long *sb_states;
+	} sbm;
 
 	/*
-	 * Mutex that protects the sbm.mb_count, sbm.mb_states, and sb_bitmap.
+	 * Mutex that protects the sbm.mb_count, sbm.mb_states, and
+	 * sbm.sb_states.
 	 *
 	 * When this lock is held the pointers can't change, ONLINE and
 	 * OFFLINE blocks can't change the state and no subblocks will get
@@ -326,13 +332,13 @@ static int virtio_mem_sbm_mb_states_prepare_next_mb(struct virtio_mem *vm)
  *
  * Will not modify the state of the memory block.
  */
-static void virtio_mem_mb_set_sb_plugged(struct virtio_mem *vm,
-					 unsigned long mb_id, int sb_id,
-					 int count)
+static void virtio_mem_sbm_set_sb_plugged(struct virtio_mem *vm,
+					  unsigned long mb_id, int sb_id,
+					  int count)
 {
 	const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb + sb_id;
 
-	__bitmap_set(vm->sb_bitmap, bit, count);
+	__bitmap_set(vm->sbm.sb_states, bit, count);
 }
 
 /*
@@ -340,86 +346,87 @@ static void virtio_mem_mb_set_sb_plugged(struct virtio_mem *vm,
  *
  * Will not modify the state of the memory block.
  */
-static void virtio_mem_mb_set_sb_unplugged(struct virtio_mem *vm,
-					   unsigned long mb_id, int sb_id,
-					   int count)
+static void virtio_mem_sbm_set_sb_unplugged(struct virtio_mem *vm,
+					    unsigned long mb_id, int sb_id,
+					    int count)
 {
 	const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb + sb_id;
 
-	__bitmap_clear(vm->sb_bitmap, bit, count);
+	__bitmap_clear(vm->sbm.sb_states, bit, count);
 }
 
 /*
  * Test if all selected subblocks are plugged.
  */
-static bool virtio_mem_mb_test_sb_plugged(struct virtio_mem *vm,
-					  unsigned long mb_id, int sb_id,
-					  int count)
+static bool virtio_mem_sbm_test_sb_plugged(struct virtio_mem *vm,
+					   unsigned long mb_id, int sb_id,
+					   int count)
 {
 	const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb + sb_id;
 
 	if (count == 1)
-		return test_bit(bit, vm->sb_bitmap);
+		return test_bit(bit, vm->sbm.sb_states);
 
 	/* TODO: Helper similar to bitmap_set() */
-	return find_next_zero_bit(vm->sb_bitmap, bit + count, bit) >=
+	return find_next_zero_bit(vm->sbm.sb_states, bit + count, bit) >=
 	       bit + count;
 }
 
 /*
  * Test if all selected subblocks are unplugged.
  */
-static bool virtio_mem_mb_test_sb_unplugged(struct virtio_mem *vm,
-					    unsigned long mb_id, int sb_id,
-					    int count)
+static bool virtio_mem_sbm_test_sb_unplugged(struct virtio_mem *vm,
+					     unsigned long mb_id, int sb_id,
+					     int count)
 {
 	const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb + sb_id;
 
 	/* TODO: Helper similar to bitmap_set() */
-	return find_next_bit(vm->sb_bitmap, bit + count, bit) >= bit + count;
+	return find_next_bit(vm->sbm.sb_states, bit + count, bit) >=
+	       bit + count;
 }
 
 /*
  * Find the first unplugged subblock. Returns vm->nb_sb_per_mb in case there is
  * none.
  */
-static int virtio_mem_mb_first_unplugged_sb(struct virtio_mem *vm,
+static int virtio_mem_sbm_first_unplugged_sb(struct virtio_mem *vm,
 					    unsigned long mb_id)
 {
 	const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb;
 
-	return find_next_zero_bit(vm->sb_bitmap, bit + vm->nb_sb_per_mb, bit) -
-	       bit;
+	return find_next_zero_bit(vm->sbm.sb_states,
+				  bit + vm->nb_sb_per_mb, bit) - bit;
 }
 
 /*
  * Prepare the subblock bitmap for the next memory block.
  */
-static int virtio_mem_sb_bitmap_prepare_next_mb(struct virtio_mem *vm)
+static int virtio_mem_sbm_sb_states_prepare_next_mb(struct virtio_mem *vm)
 {
 	const unsigned long old_nb_mb = vm->next_mb_id - vm->first_mb_id;
 	const unsigned long old_nb_bits = old_nb_mb * vm->nb_sb_per_mb;
 	const unsigned long new_nb_bits = (old_nb_mb + 1) * vm->nb_sb_per_mb;
 	int old_pages = PFN_UP(BITS_TO_LONGS(old_nb_bits) * sizeof(long));
 	int new_pages = PFN_UP(BITS_TO_LONGS(new_nb_bits) * sizeof(long));
-	unsigned long *new_sb_bitmap, *old_sb_bitmap;
+	unsigned long *new_bitmap, *old_bitmap;
 
-	if (vm->sb_bitmap && old_pages == new_pages)
+	if (vm->sbm.sb_states && old_pages == new_pages)
 		return 0;
 
-	new_sb_bitmap = vzalloc(new_pages * PAGE_SIZE);
-	if (!new_sb_bitmap)
+	new_bitmap = vzalloc(new_pages * PAGE_SIZE);
+	if (!new_bitmap)
 		return -ENOMEM;
 
 	mutex_lock(&vm->hotplug_mutex);
-	if (new_sb_bitmap)
-		memcpy(new_sb_bitmap, vm->sb_bitmap, old_pages * PAGE_SIZE);
+	if (new_bitmap)
+		memcpy(new_bitmap, vm->sbm.sb_states, old_pages * PAGE_SIZE);
 
-	old_sb_bitmap = vm->sb_bitmap;
-	vm->sb_bitmap = new_sb_bitmap;
+	old_bitmap = vm->sbm.sb_states;
+	vm->sbm.sb_states = new_bitmap;
 	mutex_unlock(&vm->hotplug_mutex);
 
-	vfree(old_sb_bitmap);
+	vfree(old_bitmap);
 	return 0;
 }
 
@@ -630,7 +637,7 @@ static void virtio_mem_notify_going_offline(struct virtio_mem *vm,
 	int sb_id;
 
 	for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
-		if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+		if (virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id, 1))
 			continue;
 		pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
 			       sb_id * vm->subblock_size);
@@ -646,7 +653,7 @@ static void virtio_mem_notify_cancel_offline(struct virtio_mem *vm,
 	int sb_id;
 
 	for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
-		if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+		if (virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id, 1))
 			continue;
 		pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
 			       sb_id * vm->subblock_size);
@@ -936,7 +943,7 @@ static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
 		 * If plugged, online the pages, otherwise, set them fake
 		 * offline (PageOffline).
 		 */
-		if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+		if (virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id, 1))
 			generic_online_page(page, order);
 		else
 			virtio_mem_set_fake_offline(PFN_DOWN(addr), 1 << order,
@@ -1071,7 +1078,7 @@ static int virtio_mem_mb_plug_sb(struct virtio_mem *vm, unsigned long mb_id,
 
 	rc = virtio_mem_send_plug_request(vm, addr, size);
 	if (!rc)
-		virtio_mem_mb_set_sb_plugged(vm, mb_id, sb_id, count);
+		virtio_mem_sbm_set_sb_plugged(vm, mb_id, sb_id, count);
 	return rc;
 }
 
@@ -1092,7 +1099,7 @@ static int virtio_mem_mb_unplug_sb(struct virtio_mem *vm, unsigned long mb_id,
 
 	rc = virtio_mem_send_unplug_request(vm, addr, size);
 	if (!rc)
-		virtio_mem_mb_set_sb_unplugged(vm, mb_id, sb_id, count);
+		virtio_mem_sbm_set_sb_unplugged(vm, mb_id, sb_id, count);
 	return rc;
 }
 
@@ -1115,14 +1122,14 @@ static int virtio_mem_mb_unplug_any_sb(struct virtio_mem *vm,
 	while (*nb_sb) {
 		/* Find the next candidate subblock */
 		while (sb_id >= 0 &&
-		       virtio_mem_mb_test_sb_unplugged(vm, mb_id, sb_id, 1))
+		       virtio_mem_sbm_test_sb_unplugged(vm, mb_id, sb_id, 1))
 			sb_id--;
 		if (sb_id < 0)
 			break;
 		/* Try to unplug multiple subblocks at a time */
 		count = 1;
 		while (count < *nb_sb && sb_id > 0 &&
-		       virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id - 1, 1)) {
+		       virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id - 1, 1)) {
 			count++;
 			sb_id--;
 		}
@@ -1168,7 +1175,7 @@ static int virtio_mem_prepare_next_mb(struct virtio_mem *vm,
 		return rc;
 
 	/* Resize the subblock bitmap if required. */
-	rc = virtio_mem_sb_bitmap_prepare_next_mb(vm);
+	rc = virtio_mem_sbm_sb_states_prepare_next_mb(vm);
 	if (rc)
 		return rc;
 
@@ -1253,14 +1260,13 @@ static int virtio_mem_mb_plug_any_sb(struct virtio_mem *vm, unsigned long mb_id,
 		return -EINVAL;
 
 	while (*nb_sb) {
-		sb_id = virtio_mem_mb_first_unplugged_sb(vm, mb_id);
+		sb_id = virtio_mem_sbm_first_unplugged_sb(vm, mb_id);
 		if (sb_id >= vm->nb_sb_per_mb)
 			break;
 		count = 1;
 		while (count < *nb_sb &&
 		       sb_id + count < vm->nb_sb_per_mb &&
-		       !virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id + count,
-						      1))
+		       !virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id + count, 1))
 			count++;
 
 		rc = virtio_mem_mb_plug_sb(vm, mb_id, sb_id, count);
@@ -1277,7 +1283,7 @@ static int virtio_mem_mb_plug_any_sb(struct virtio_mem *vm, unsigned long mb_id,
 		virtio_mem_fake_online(pfn, nr_pages);
 	}
 
-	if (virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
+	if (virtio_mem_sbm_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
 		if (online)
 			virtio_mem_sbm_set_mb_state(vm, mb_id,
 						    VIRTIO_MEM_SBM_MB_ONLINE);
@@ -1377,13 +1383,13 @@ static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm,
 	rc = virtio_mem_mb_unplug_any_sb(vm, mb_id, nb_sb);
 
 	/* some subblocks might have been unplugged even on failure */
-	if (!virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb))
+	if (!virtio_mem_sbm_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb))
 		virtio_mem_sbm_set_mb_state(vm, mb_id,
 					    VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL);
 	if (rc)
 		return rc;
 
-	if (virtio_mem_mb_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
+	if (virtio_mem_sbm_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
 		/*
 		 * Remove the block from Linux - this should never fail.
 		 * Hinder the block from getting onlined by marking it
@@ -1452,7 +1458,7 @@ static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm,
 
 	/* If possible, try to unplug the complete block in one shot. */
 	if (*nb_sb >= vm->nb_sb_per_mb &&
-	    virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
+	    virtio_mem_sbm_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
 		rc = virtio_mem_mb_unplug_sb_online(vm, mb_id, 0,
 						    vm->nb_sb_per_mb);
 		if (!rc) {
@@ -1466,7 +1472,7 @@ static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm,
 	for (sb_id = vm->nb_sb_per_mb - 1; sb_id >= 0 && *nb_sb; sb_id--) {
 		/* Find the next candidate subblock */
 		while (sb_id >= 0 &&
-		       !virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+		       !virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id, 1))
 			sb_id--;
 		if (sb_id < 0)
 			break;
@@ -1485,7 +1491,7 @@ static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm,
 	 * remove it. This will usually not fail, as no memory is in use
 	 * anymore - however some other notifiers might NACK the request.
 	 */
-	if (virtio_mem_mb_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
+	if (virtio_mem_sbm_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
 		mutex_unlock(&vm->hotplug_mutex);
 		rc = virtio_mem_mb_offline_and_remove(vm, mb_id);
 		mutex_lock(&vm->hotplug_mutex);
@@ -2007,7 +2013,7 @@ static void virtio_mem_remove(struct virtio_device *vdev)
 
 	/* remove all tracking data - no locking needed */
 	vfree(vm->sbm.mb_states);
-	vfree(vm->sb_bitmap);
+	vfree(vm->sbm.sb_states);
 
 	/* reset the device and cleanup the queues */
 	vdev->config->reset(vdev);
-- 
2.26.2