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@redhat.com --- 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 */