Patch "iommufd: Add iopt_area_alloc()" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iommufd: Add iopt_area_alloc()

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iommufd-add-iopt_area_alloc.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5a1b12c372f03a7c77d14ccdc2fae6c5bd6ec57f
Author: Jason Gunthorpe <jgg@xxxxxxxx>
Date:   Mon Oct 30 11:26:33 2023 -0300

    iommufd: Add iopt_area_alloc()
    
    [ Upstream commit 361d744ddd61de065fbeb042aaed590d32dd92ec ]
    
    We never initialize the two interval tree nodes, and zero fill is not the
    same as RB_CLEAR_NODE. This can hide issues where we missed adding the
    area to the trees. Factor out the allocation and clear the two nodes.
    
    Fixes: 51fe6141f0f6 ("iommufd: Data structure to provide IOVA to PFN mapping")
    Link: https://lore.kernel.org/r/20231030145035.GG691768@xxxxxxxx
    Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iommu/iommufd/io_pagetable.c b/drivers/iommu/iommufd/io_pagetable.c
index 3a598182b7619..a4da1817e19dd 100644
--- a/drivers/iommu/iommufd/io_pagetable.c
+++ b/drivers/iommu/iommufd/io_pagetable.c
@@ -221,6 +221,18 @@ static int iopt_insert_area(struct io_pagetable *iopt, struct iopt_area *area,
 	return 0;
 }
 
+static struct iopt_area *iopt_area_alloc(void)
+{
+	struct iopt_area *area;
+
+	area = kzalloc(sizeof(*area), GFP_KERNEL_ACCOUNT);
+	if (!area)
+		return NULL;
+	RB_CLEAR_NODE(&area->node.rb);
+	RB_CLEAR_NODE(&area->pages_node.rb);
+	return area;
+}
+
 static int iopt_alloc_area_pages(struct io_pagetable *iopt,
 				 struct list_head *pages_list,
 				 unsigned long length, unsigned long *dst_iova,
@@ -231,7 +243,7 @@ static int iopt_alloc_area_pages(struct io_pagetable *iopt,
 	int rc = 0;
 
 	list_for_each_entry(elm, pages_list, next) {
-		elm->area = kzalloc(sizeof(*elm->area), GFP_KERNEL_ACCOUNT);
+		elm->area = iopt_area_alloc();
 		if (!elm->area)
 			return -ENOMEM;
 	}
@@ -1005,11 +1017,11 @@ static int iopt_area_split(struct iopt_area *area, unsigned long iova)
 	    iopt_area_start_byte(area, new_start) & (alignment - 1))
 		return -EINVAL;
 
-	lhs = kzalloc(sizeof(*area), GFP_KERNEL_ACCOUNT);
+	lhs = iopt_area_alloc();
 	if (!lhs)
 		return -ENOMEM;
 
-	rhs = kzalloc(sizeof(*area), GFP_KERNEL_ACCOUNT);
+	rhs = iopt_area_alloc();
 	if (!rhs) {
 		rc = -ENOMEM;
 		goto err_free_lhs;
diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index 8d9aa297c117e..528f356238b34 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -1507,6 +1507,8 @@ void iopt_area_unfill_domains(struct iopt_area *area, struct iopt_pages *pages)
 				area, domain, iopt_area_index(area),
 				iopt_area_last_index(area));
 
+	if (IS_ENABLED(CONFIG_IOMMUFD_TEST))
+		WARN_ON(RB_EMPTY_NODE(&area->pages_node.rb));
 	interval_tree_remove(&area->pages_node, &pages->domains_itree);
 	iopt_area_unfill_domain(area, pages, area->storage_domain);
 	area->storage_domain = NULL;