[PATCH v2 07/11] iommu/amd: Use put_pages_list

Robin Murphy
2021-12-10T17:55:22Z

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

page->freelist is for the use of slab. We already have the ability
to free a list of pages in the core mm, but it requires the use of a
list_head and for the pages to be chained together through page->lru.
Switch the AMD IOMMU code over to using free_pages_list().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
[rm: split from original patch, cosmetic tweaks]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v2: No change

drivers/iommu/amd/io_pgtable.c | 50 ++++++++++++----------------------
1 file changed, 18 insertions(+), 32 deletions(-)

diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c
index 4165e1372b6e..b1bf4125b0f7 100644
--- a/drivers/iommu/amd/io_pgtable.c
+++ b/drivers/iommu/amd/io_pgtable.c
@@ -74,26 +74,14 @@ static u64 *first_pte_l7(u64 *pte, unsigned long *page_size,
*
****************************************************************************/

-static void free_page_list(struct page *freelist)
-{
- while (freelist != NULL) {
- unsigned long p = (unsigned long)page_address(freelist);
-
- freelist = freelist->freelist;
- free_page(p);
- }
-}
-
-static struct page *free_pt_page(u64 *pt, struct page *freelist)
+static void free_pt_page(u64 *pt, struct list_head *freelist)
{
struct page *p = virt_to_page(pt);

- p->freelist = freelist;
-
- return p;
+ list_add_tail(&p->lru, freelist);
}

-static struct page *free_pt_lvl(u64 *pt, struct page *freelist, int lvl)
+static void free_pt_lvl(u64 *pt, struct list_head *freelist, int lvl)
{
u64 *p;
int i;
@@ -114,22 +102,22 @@ static struct page *free_pt_lvl(u64 *pt, struct page *freelist, int lvl)
*/
p = IOMMU_PTE_PAGE(pt[i]);
if (lvl > 2)
- freelist = free_pt_lvl(p, freelist, lvl - 1);
+ free_pt_lvl(p, freelist, lvl - 1);
else
- freelist = free_pt_page(p, freelist);
+ free_pt_page(p, freelist);
}

- return free_pt_page(pt, freelist);
+ free_pt_page(pt, freelist);
}

-static struct page *free_sub_pt(u64 *root, int mode, struct page *freelist)
+static void free_sub_pt(u64 *root, int mode, struct list_head *freelist)
{
switch (mode) {
case PAGE_MODE_NONE:
case PAGE_MODE_7_LEVEL:
break;
case PAGE_MODE_1_LEVEL:
- freelist = free_pt_page(root, freelist);
+ free_pt_page(root, freelist);
break;
case PAGE_MODE_2_LEVEL:
case PAGE_MODE_3_LEVEL:
@@ -141,8 +129,6 @@ static struct page *free_sub_pt(u64 *root, int mode, struct page *freelist)
default:
BUG();
}
-
- return freelist;
}

void amd_iommu_domain_set_pgtable(struct protection_domain *domain,
@@ -350,7 +336,7 @@ static u64 *fetch_pte(struct amd_io_pgtable *pgtable,
return pte;
}

-static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist)
+static void free_clear_pte(u64 *pte, u64 pteval, struct list_head *freelist)
{
u64 *pt;
int mode;
@@ -361,12 +347,12 @@ static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist)
}

if (!IOMMU_PTE_PRESENT(pteval))
- return freelist;
+ return;

pt = IOMMU_PTE_PAGE(pteval);
mode = IOMMU_PTE_MODE(pteval);

- return free_sub_pt(pt, mode, freelist);
+ free_sub_pt(pt, mode, freelist);
}

/*
@@ -380,7 +366,7 @@ static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
{
struct protection_domain *dom = io_pgtable_ops_to_domain(ops);
- struct page *freelist = NULL;
+ LIST_HEAD(freelist);
bool updated = false;
u64 __pte, *pte;
int ret, i, count;
@@ -400,9 +386,9 @@ static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
goto out;

for (i = 0; i < count; ++i)
- freelist = free_clear_pte(&pte[i], pte[i], freelist);
+ free_clear_pte(&pte[i], pte[i], &freelist);

- if (freelist != NULL)
+ if (!list_empty(&freelist))
updated = true;

if (count > 1) {
@@ -437,7 +423,7 @@ static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
}

/* Everything flushed out, free pages now */
- free_page_list(freelist);
+ put_pages_list(&freelist);

return ret;
}
@@ -499,7 +485,7 @@ static void v1_free_pgtable(struct io_pgtable *iop)
{
struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop);
struct protection_domain *dom;
- struct page *freelist = NULL;
+ LIST_HEAD(freelist);

if (pgtable->mode == PAGE_MODE_NONE)
return;
@@ -516,9 +502,9 @@ static void v1_free_pgtable(struct io_pgtable *iop)
BUG_ON(pgtable->mode < PAGE_MODE_NONE ||
pgtable->mode > PAGE_MODE_6_LEVEL);

- freelist = free_sub_pt(pgtable->root, pgtable->mode, freelist);
+ free_sub_pt(pgtable->root, pgtable->mode, &freelist);

- free_page_list(freelist);
+ put_pages_list(&freelist);
}

static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
--
2.28.0.dirty