mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 13:51:44 +00:00
5189686457
get_user_pages_fast() will return negative value if no pages were pinned,
then be converted to a unsigned, which is compared to zero, giving the
wrong result.
Link: http://lkml.kernel.org/r/20180921095015.26088-1-yuehaibing@huawei.com
Fixes: 09e35a4a1c ("mm/gup_benchmark: handle gup failures")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
104 lines
2.1 KiB
C
104 lines
2.1 KiB
C
#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_benchmark)
|
|
|
|
struct gup_benchmark {
|
|
__u64 delta_usec;
|
|
__u64 addr;
|
|
__u64 size;
|
|
__u32 nr_pages_per_call;
|
|
__u32 flags;
|
|
};
|
|
|
|
static int __gup_benchmark_ioctl(unsigned int cmd,
|
|
struct gup_benchmark *gup)
|
|
{
|
|
ktime_t start_time, end_time;
|
|
unsigned long i, nr_pages, addr, next;
|
|
int nr;
|
|
struct page **pages;
|
|
|
|
nr_pages = gup->size / PAGE_SIZE;
|
|
pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
|
|
if (!pages)
|
|
return -ENOMEM;
|
|
|
|
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;
|
|
}
|
|
|
|
nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i);
|
|
if (nr <= 0)
|
|
break;
|
|
i += nr;
|
|
}
|
|
end_time = ktime_get();
|
|
|
|
gup->delta_usec = ktime_us_delta(end_time, start_time);
|
|
gup->size = addr - gup->addr;
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
if (!pages[i])
|
|
break;
|
|
put_page(pages[i]);
|
|
}
|
|
|
|
kvfree(pages);
|
|
return 0;
|
|
}
|
|
|
|
static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct gup_benchmark gup;
|
|
int ret;
|
|
|
|
if (cmd != GUP_FAST_BENCHMARK)
|
|
return -EINVAL;
|
|
|
|
if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
|
|
return -EFAULT;
|
|
|
|
ret = __gup_benchmark_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_benchmark_fops = {
|
|
.open = nonseekable_open,
|
|
.unlocked_ioctl = gup_benchmark_ioctl,
|
|
};
|
|
|
|
static int gup_benchmark_init(void)
|
|
{
|
|
void *ret;
|
|
|
|
ret = debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
|
|
&gup_benchmark_fops);
|
|
if (!ret)
|
|
pr_warn("Failed to create gup_benchmark in debugfs");
|
|
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(gup_benchmark_init);
|