habanalabs: fix H/W block handling for partial unmappings

Several munmap() calls can be done or a mapped H/W block that has a
larger size than a page size.
Releasing the object should be done only when all mapped range is
unmapped.
Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

drivers/misc/habanalabs/common/debugfs.c

@@ -291,14 +291,16 @@ static int vm_show(struct seq_file *s, void *data)
 		if (ctx->asid != HL_KERNEL_ASID_ID &&
 		    !list_empty(&ctx->hw_block_mem_list)) {
 			seq_puts(s, "\nhw_block mappings:\n\n");
-			seq_puts(s, "    virtual address    size    HW block id\n");
-			seq_puts(s, "-------------------------------------------\n");
+			seq_puts(s,
+				"    virtual address    block size    mapped size    HW block id\n");
+			seq_puts(s,
+				"---------------------------------------------------------------\n");
 			mutex_lock(&ctx->hw_block_list_lock);
-			list_for_each_entry(lnode, &ctx->hw_block_mem_list,
-					    node) {
+			list_for_each_entry(lnode, &ctx->hw_block_mem_list, node) {
 				seq_printf(s,
-					"    0x%-14lx   %-6u      %-9u\n",
-					lnode->vaddr, lnode->size, lnode->id);
+					"    0x%-14lx   %-6u        %-6u             %-9u\n",
+					lnode->vaddr, lnode->block_size, lnode->mapped_size,
+					lnode->id);
 			}
 			mutex_unlock(&ctx->hw_block_list_lock);
 		}

drivers/misc/habanalabs/common/habanalabs.h

@@ -2063,14 +2063,16 @@ struct hl_vm_hash_node {
  * @node: node to hang on the list in context object.
  * @ctx: the context this node belongs to.
  * @vaddr: virtual address of the HW block.
- * @size: size of the block.
+ * @block_size: size of the block.
+ * @mapped_size: size of the block which is mapped. May change if partial un-mappings are done.
  * @id: HW block id (handle).
  */
 struct hl_vm_hw_block_list_node {
 	struct list_head	node;
 	struct hl_ctx		*ctx;
 	unsigned long		vaddr;
-	u32			size;
+	u32			block_size;
+	u32			mapped_size;
 	u32			id;
 };
 

drivers/misc/habanalabs/common/memory.c

@@ -1442,6 +1442,13 @@ static void hw_block_vm_close(struct vm_area_struct *vma)
 	struct hl_vm_hw_block_list_node *lnode =
 		(struct hl_vm_hw_block_list_node *) vma->vm_private_data;
 	struct hl_ctx *ctx = lnode->ctx;
+	long new_mmap_size;
+
+	new_mmap_size = lnode->mapped_size - (vma->vm_end - vma->vm_start);
+	if (new_mmap_size > 0) {
+		lnode->mapped_size = new_mmap_size;
+		return;
+	}
 
 	mutex_lock(&ctx->hw_block_list_lock);
 	list_del(&lnode->node);
@@ -1502,7 +1509,8 @@ int hl_hw_block_mmap(struct hl_fpriv *hpriv, struct vm_area_struct *vma)
 
 	lnode->ctx = ctx;
 	lnode->vaddr = vma->vm_start;
-	lnode->size = block_size;
+	lnode->block_size = block_size;
+	lnode->mapped_size = lnode->block_size;
 	lnode->id = block_id;
 
 	vma->vm_private_data = lnode;