We want to get rid of struct page references outside the internal
allocator implementation. The free list has the driver open code something
like:
list_add_tail(&virt_to_page(ptr)->lru, freelist);
Move the above into a small inline and make the freelist into a wrapper
type 'struct iommu_pages_list' so that the compiler can help check all the
conversion.
This struct has also proven helpful in some future ideas to convert to a
singly linked list to get an extra pointer in the struct page, and to
signal that the pages should be freed with RCU.
Use a temporary _Generic so we don't need to rename the free function as
the patches progress.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/iommu/iommu-pages.c | 23 ++++++++++++-------
drivers/iommu/iommu-pages.h | 45 ++++++++++++++++++++++++++++++++++---
include/linux/iommu.h | 12 ++++++++++
3 files changed, 69 insertions(+), 11 deletions(-)
diff --git a/drivers/iommu/iommu-pages.c b/drivers/iommu/iommu-pages.c
index 0fece3758408ae..92a6966ad4c032 100644
--- a/drivers/iommu/iommu-pages.c
+++ b/drivers/iommu/iommu-pages.c
@@ -67,18 +67,25 @@ void iommu_free_page(void *virt)
EXPORT_SYMBOL_GPL(iommu_free_page);
/**
- * iommu_put_pages_list - free a list of pages.
- * @head: the head of the lru list to be freed.
+ * iommu_put_pages_list_new - free a list of pages.
+ * @list: The list of pages to be freed
*
* Frees a list of pages allocated by iommu_alloc_pages_node().
*/
-void iommu_put_pages_list(struct list_head *head)
+void iommu_put_pages_list_new(struct iommu_pages_list *list)
{
- while (!list_empty(head)) {
- struct page *p = list_entry(head->prev, struct page, lru);
+ struct page *p, *tmp;
- list_del(&p->lru);
+ list_for_each_entry_safe(p, tmp, &list->pages, lru)
__iommu_free_page(p);
- }
}
-EXPORT_SYMBOL_GPL(iommu_put_pages_list);
+EXPORT_SYMBOL_GPL(iommu_put_pages_list_new);
+
+void iommu_put_pages_list_old(struct list_head *head)
+{
+ struct page *p, *tmp;
+
+ list_for_each_entry_safe(p, tmp, head, lru)
+ __iommu_free_page(p);
+}
+EXPORT_SYMBOL_GPL(iommu_put_pages_list_old);
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
index 6045e1f90a40cb..0950f7c0cae9eb 100644
--- a/drivers/iommu/iommu-pages.h
+++ b/drivers/iommu/iommu-pages.h
@@ -7,12 +7,51 @@
#ifndef __IOMMU_PAGES_H
#define __IOMMU_PAGES_H
-#include <linux/types.h>
-#include <linux/topology.h>
+#include <linux/iommu.h>
void *iommu_alloc_pages_node(int nid, gfp_t gfp, unsigned int order);
void iommu_free_page(void *virt);
-void iommu_put_pages_list(struct list_head *head);
+void iommu_put_pages_list_new(struct iommu_pages_list *list);
+void iommu_put_pages_list_old(struct list_head *head);
+
+#define iommu_put_pages_list(head) \
+ _Generic(head, \
+ struct iommu_pages_list *: iommu_put_pages_list_new, \
+ struct list_head *: iommu_put_pages_list_old)(head)
+
+/**
+ * iommu_pages_list_add - add the page to a iommu_pages_list
+ * @list: List to add the page to
+ * @virt: Address returned from iommu_alloc_pages_node()
+ */
+static inline void iommu_pages_list_add(struct iommu_pages_list *list,
+ void *virt)
+{
+ list_add_tail(&virt_to_page(virt)->lru, &list->pages);
+}
+
+/**
+ * iommu_pages_list_splice - Put all the pages in list from into list to
+ * @from: Source list of pages
+ * @to: Destination list of pages
+ *
+ * from must be re-initialized after calling this function if it is to be
+ * used again.
+ */
+static inline void iommu_pages_list_splice(struct iommu_pages_list *from,
+ struct iommu_pages_list *to)
+{
+ list_splice(&from->pages, &to->pages);
+}
+
+/**
+ * iommu_pages_list_empty - True if the list is empty
+ * @list: List to check
+ */
+static inline bool iommu_pages_list_empty(struct iommu_pages_list *list)
+{
+ return list_empty(&list->pages);
+}
/**
* iommu_alloc_pages - allocate a zeroed page of a given order
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 38c65e92ecd091..e414951c0af83f 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -326,6 +326,18 @@ typedef unsigned int ioasid_t;
/* Read but do not clear any dirty bits */
#define IOMMU_DIRTY_NO_CLEAR (1 << 0)
+/*
+ * Pages allocated through iommu_alloc_pages_node() can be placed on this list
+ * using iommu_pages_list_add(). Note: ONLY pages from iommu_alloc_pages_node()
+ * can be used this way!
+ */
+struct iommu_pages_list {
+ struct list_head pages;
+};
+
+#define IOMMU_PAGES_LIST_INIT(name) \
+ ((struct iommu_pages_list){ .pages = LIST_HEAD_INIT(name.pages) })
+
#ifdef CONFIG_IOMMU_API
/**
--
2.43.0
