We want an easy way to take a R/O or R/W longterm pin on a range and be
able to observe the content of the pinned pages, so we can properly test
how longterm puns interact with our COW logic.
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
mm/gup_test.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++
mm/gup_test.h | 12 +++++
2 files changed, 152 insertions(+)
diff --git a/mm/gup_test.c b/mm/gup_test.c
index 12b0a91767d3..2bbfacd31f5a 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -203,6 +203,134 @@ static int __gup_test_ioctl(unsigned int cmd,
return ret;
}
+static DEFINE_MUTEX(pin_longterm_test_mutex);
+static struct page **pin_longterm_test_pages;
+static unsigned long pin_longterm_test_nr_pages;
+
+static inline void pin_longterm_test_stop(void)
+{
+ if (pin_longterm_test_pages) {
+ if (pin_longterm_test_nr_pages)
+ unpin_user_pages(pin_longterm_test_pages,
+ pin_longterm_test_nr_pages);
+ kfree(pin_longterm_test_pages);
+ pin_longterm_test_pages = NULL;
+ pin_longterm_test_nr_pages = 0;
+ }
+}
+
+static inline int pin_longterm_test_start(unsigned long arg)
+{
+ long nr_pages, cur_pages, addr, remaining_pages;
+ int gup_flags = FOLL_LONGTERM;
+ struct pin_longterm_test args;
+ struct page **pages;
+ int ret = 0;
+ bool fast;
+
+ if (pin_longterm_test_pages)
+ return -EINVAL;
+
+ if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
+ return -EFAULT;
+
+ if (args.flags &
+ ~(PIN_LONGTERM_TEST_FLAG_USE_WRITE|PIN_LONGTERM_TEST_FLAG_USE_FAST))
+ return -EINVAL;
+ if (!IS_ALIGNED(args.addr | args.size, PAGE_SIZE))
+ return -EINVAL;
+ if (args.size > LONG_MAX)
+ return -EINVAL;
+ nr_pages = args.size / PAGE_SIZE;
+ if (!nr_pages)
+ return -EINVAL;
+
+ pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
+ if (!pages)
+ return -ENOMEM;
+
+ if (args.flags & PIN_LONGTERM_TEST_FLAG_USE_WRITE)
+ gup_flags |= FOLL_WRITE;
+ fast = !!(args.flags & PIN_LONGTERM_TEST_FLAG_USE_FAST);
+
+ if (!fast && mmap_read_lock_killable(current->mm)) {
+ kfree(pages);
+ return -EINTR;
+ }
+
+ pin_longterm_test_pages = pages;
+ pin_longterm_test_nr_pages = 0;
+
+ while (nr_pages - pin_longterm_test_nr_pages) {
+ remaining_pages = nr_pages - pin_longterm_test_nr_pages;
+ addr = args.addr + pin_longterm_test_nr_pages * PAGE_SIZE;
+
+ if (fast)
+ cur_pages = pin_user_pages_fast(addr, remaining_pages,
+ gup_flags, pages);
+ else
+ cur_pages = pin_user_pages(addr, remaining_pages,
+ gup_flags, pages, NULL);
+ if (cur_pages < 0) {
+ pin_longterm_test_stop();
+ ret = cur_pages;
+ break;
+ }
+ pin_longterm_test_nr_pages += cur_pages;
+ pages += cur_pages;
+ };
+
+ if (!fast)
+ mmap_read_unlock(current->mm);
+ return ret;
+}
+
+static inline int pin_longterm_test_read(unsigned long arg)
+{
+ __u64 user_addr;
+ unsigned long i;
+
+ if (!pin_longterm_test_pages)
+ return -EINVAL;
+
+ if (copy_from_user(&user_addr, (void __user *)arg, sizeof(user_addr)))
+ return -EFAULT;
+
+ for (i = 0; i < pin_longterm_test_nr_pages; i++) {
+ void *addr = page_to_virt(pin_longterm_test_pages[i]);
+
+ if (copy_to_user((void __user *)user_addr, addr, PAGE_SIZE))
+ return -EFAULT;
+ user_addr += PAGE_SIZE;
+ }
+ return 0;
+}
+
+static long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,
+ unsigned long arg)
+{
+ int ret = -EINVAL;
+
+ if (mutex_lock_killable(&pin_longterm_test_mutex))
+ return -EINTR;
+
+ switch (cmd) {
+ case PIN_LONGTERM_TEST_START:
+ ret = pin_longterm_test_start(arg);
+ break;
+ case PIN_LONGTERM_TEST_STOP:
+ pin_longterm_test_stop();
+ ret = 0;
+ break;
+ case PIN_LONGTERM_TEST_READ:
+ ret = pin_longterm_test_read(arg);
+ break;
+ }
+
+ mutex_unlock(&pin_longterm_test_mutex);
+ return ret;
+}
+
static long gup_test_ioctl(struct file *filep, unsigned int cmd,
unsigned long arg)
{
@@ -217,6 +345,10 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd,
case PIN_BASIC_TEST:
case DUMP_USER_PAGES_TEST:
break;
+ case PIN_LONGTERM_TEST_START:
+ case PIN_LONGTERM_TEST_STOP:
+ case PIN_LONGTERM_TEST_READ:
+ return pin_longterm_test_ioctl(filep, cmd, arg);
default:
return -EINVAL;
}
@@ -234,9 +366,17 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd,
return 0;
}
+static int gup_test_release(struct inode *inode, struct file *file)
+{
+ pin_longterm_test_stop();
+
+ return 0;
+}
+
static const struct file_operations gup_test_fops = {
.open = nonseekable_open,
.unlocked_ioctl = gup_test_ioctl,
+ .release = gup_test_release,
};
static int __init gup_test_init(void)
diff --git a/mm/gup_test.h b/mm/gup_test.h
index 887ac1d5f5bc..5b37b54e8bea 100644
--- a/mm/gup_test.h
+++ b/mm/gup_test.h
@@ -10,6 +10,9 @@
#define GUP_BASIC_TEST _IOWR('g', 4, struct gup_test)
#define PIN_BASIC_TEST _IOWR('g', 5, struct gup_test)
#define DUMP_USER_PAGES_TEST _IOWR('g', 6, struct gup_test)
+#define PIN_LONGTERM_TEST_START _IOW('g', 7, struct pin_longterm_test)
+#define PIN_LONGTERM_TEST_STOP _IO('g', 8)
+#define PIN_LONGTERM_TEST_READ _IOW('g', 9, __u64)
#define GUP_TEST_MAX_PAGES_TO_DUMP 8
@@ -30,4 +33,13 @@ struct gup_test {
__u32 which_pages[GUP_TEST_MAX_PAGES_TO_DUMP];
};
+#define PIN_LONGTERM_TEST_FLAG_USE_WRITE 1
+#define PIN_LONGTERM_TEST_FLAG_USE_FAST 2
+
+struct pin_longterm_test {
+ __u64 addr;
+ __u64 size;
+ __u32 flags;
+};
+
#endif /* __GUP_TEST_H */
--
2.37.3
