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#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/ktime.h>
#include <linux/debugfs.h>
#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_test)
#define GUP_BENCHMARK _IOWR('g', 2, struct gup_test)
#define PIN_FAST_BENCHMARK _IOWR('g', 3, struct gup_test)
#define PIN_BENCHMARK _IOWR('g', 4, struct gup_test)
#define PIN_LONGTERM_BENCHMARK _IOWR('g', 5, struct gup_test)
struct gup_test {
__u64 get_delta_usec;
__u64 put_delta_usec;
__u64 addr;
__u64 size;
__u32 nr_pages_per_call;
__u32 flags;
__u64 expansion[10]; /* For future use */
};
static void put_back_pages(unsigned int cmd, struct page **pages,
unsigned long nr_pages)
{
unsigned long i;
switch (cmd) {
case GUP_FAST_BENCHMARK:
case GUP_BENCHMARK:
for (i = 0; i < nr_pages; i++)
put_page(pages[i]);
break;
case PIN_FAST_BENCHMARK:
case PIN_BENCHMARK:
case PIN_LONGTERM_BENCHMARK:
unpin_user_pages(pages, nr_pages);
break;
}
}
static void verify_dma_pinned(unsigned int cmd, struct page **pages,
unsigned long nr_pages)
{
unsigned long i;
struct page *page;
switch (cmd) {
case PIN_FAST_BENCHMARK:
case PIN_BENCHMARK:
case PIN_LONGTERM_BENCHMARK:
for (i = 0; i < nr_pages; i++) {
page = pages[i];
if (WARN(!page_maybe_dma_pinned(page),
"pages[%lu] is NOT dma-pinned\n", i)) {
dump_page(page, "gup_test failure");
break;
}
}
break;
}
}
static int __gup_test_ioctl(unsigned int cmd,
struct gup_test *gup)
{
ktime_t start_time, end_time;
unsigned long i, nr_pages, addr, next;
int nr;
struct page **pages;
int ret = 0;
bool needs_mmap_lock =
cmd != GUP_FAST_BENCHMARK && cmd != PIN_FAST_BENCHMARK;
if (gup->size > ULONG_MAX)
return -EINVAL;
nr_pages = gup->size / PAGE_SIZE;
pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
if (!pages)
return -ENOMEM;
if (needs_mmap_lock && mmap_read_lock_killable(current->mm)) {
ret = -EINTR;
goto free_pages;
}
i = 0;
nr = gup->nr_pages_per_call;
start_time = ktime_get();
for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
if (nr != gup->nr_pages_per_call)
break;
next = addr + nr * PAGE_SIZE;
if (next > gup->addr + gup->size) {
next = gup->addr + gup->size;
nr = (next - addr) / PAGE_SIZE;
}
/* Filter out most gup flags: only allow a tiny subset here: */
gup->flags &= FOLL_WRITE;
switch (cmd) {
case GUP_FAST_BENCHMARK:
nr = get_user_pages_fast(addr, nr, gup->flags,
pages + i);
break;
case GUP_BENCHMARK:
nr = get_user_pages(addr, nr, gup->flags, pages + i,
NULL);
break;
case PIN_FAST_BENCHMARK:
nr = pin_user_pages_fast(addr, nr, gup->flags,
pages + i);
break;
case PIN_BENCHMARK:
nr = pin_user_pages(addr, nr, gup->flags, pages + i,
NULL);
break;
case PIN_LONGTERM_BENCHMARK:
nr = pin_user_pages(addr, nr,
gup->flags | FOLL_LONGTERM,
pages + i, NULL);
break;
default:
ret = -EINVAL;
goto unlock;
}
if (nr <= 0)
break;
i += nr;
}
end_time = ktime_get();
/* Shifting the meaning of nr_pages: now it is actual number pinned: */
nr_pages = i;
gup->get_delta_usec = ktime_us_delta(end_time, start_time);
gup->size = addr - gup->addr;
/*
* Take an un-benchmark-timed moment to verify DMA pinned
* state: print a warning if any non-dma-pinned pages are found:
*/
verify_dma_pinned(cmd, pages, nr_pages);
start_time = ktime_get();
put_back_pages(cmd, pages, nr_pages);
end_time = ktime_get();
gup->put_delta_usec = ktime_us_delta(end_time, start_time);
unlock:
if (needs_mmap_lock)
mmap_read_unlock(current->mm);
free_pages:
kvfree(pages);
return ret;
}
static long gup_test_ioctl(struct file *filep, unsigned int cmd,
unsigned long arg)
{
struct gup_test gup;
int ret;
switch (cmd) {
case GUP_FAST_BENCHMARK:
case GUP_BENCHMARK:
case PIN_FAST_BENCHMARK:
case PIN_BENCHMARK:
case PIN_LONGTERM_BENCHMARK:
break;
default:
return -EINVAL;
}
if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
return -EFAULT;
ret = __gup_test_ioctl(cmd, &gup);
if (ret)
return ret;
if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
return -EFAULT;
return 0;
}
static const struct file_operations gup_test_fops = {
.open = nonseekable_open,
.unlocked_ioctl = gup_test_ioctl,
};
static int gup_test_init(void)
{
debugfs_create_file_unsafe("gup_test", 0600, NULL, NULL,
&gup_test_fops);
return 0;
}
late_initcall(gup_test_init);
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