xen_mm_pin_all()/unpin_all() are used to implement full guest instance
suspend/restore. It's a stop-all method that needs to iterate through
all allocated pgds in the system to fix them up for Xen's use.
This code uses pgd_list, probably because it was an easy interface.
But we want to remove the pgd_list, so convert the code over to walk
all tasks in the system. This is an equivalent method.
(As I don't use Xen this is was only build tested.)
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Waiman Long <Waiman.Long@xxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/xen/mmu.c | 51 ++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 38 insertions(+), 13 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index dd151b2045b0..70a3df5b0b54 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -853,15 +853,27 @@ static void xen_pgd_pin(struct mm_struct *mm)
*/
void xen_mm_pin_all(void)
{
- struct page *page;
+ struct task_struct *g, *p;
- spin_lock(&pgd_lock);
+ spin_lock(&pgd_lock); /* Implies rcu_read_lock() for the task list iteration: */
- list_for_each_entry(page, &pgd_list, lru) {
- if (!PagePinned(page)) {
- __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
- SetPageSavePinned(page);
+ for_each_process_thread(g, p) {
+ struct mm_struct *mm;
+ struct page *page;
+ pgd_t *pgd;
+
+ task_lock(p);
+ mm = p->mm;
+ if (mm) {
+ pgd = mm->pgd;
+ page = virt_to_page(pgd);
+
+ if (!PagePinned(page)) {
+ __xen_pgd_pin(&init_mm, pgd);
+ SetPageSavePinned(page);
+ }
}
+ task_unlock(p);
}
spin_unlock(&pgd_lock);
@@ -967,19 +979,32 @@ static void xen_pgd_unpin(struct mm_struct *mm)
*/
void xen_mm_unpin_all(void)
{
- struct page *page;
+ struct task_struct *g, *p;
- spin_lock(&pgd_lock);
+ spin_lock(&pgd_lock); /* Implies rcu_read_lock() for the task list iteration: */
- list_for_each_entry(page, &pgd_list, lru) {
- if (PageSavePinned(page)) {
- BUG_ON(!PagePinned(page));
- __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
- ClearPageSavePinned(page);
+ for_each_process_thread(g, p) {
+ struct mm_struct *mm;
+ struct page *page;
+ pgd_t *pgd;
+
+ task_lock(p);
+ mm = p->mm;
+ if (mm) {
+ pgd = mm->pgd;
+ page = virt_to_page(pgd);
+
+ if (PageSavePinned(page)) {
+ BUG_ON(!PagePinned(page));
+ __xen_pgd_unpin(&init_mm, pgd);
+ ClearPageSavePinned(page);
+ }
}
+ task_unlock(p);
}
spin_unlock(&pgd_lock);
+ rcu_read_unlock();
}
static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
--
2.1.4
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