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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Link: http://lkml.kernel.org/r/20190122152151.16139-14-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Laura Abbott <labbott@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
131 lines
2.7 KiB
C
131 lines
2.7 KiB
C
#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/ktime.h>
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#include <linux/debugfs.h>
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#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_benchmark)
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#define GUP_LONGTERM_BENCHMARK _IOWR('g', 2, struct gup_benchmark)
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#define GUP_BENCHMARK _IOWR('g', 3, struct gup_benchmark)
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struct gup_benchmark {
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__u64 get_delta_usec;
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__u64 put_delta_usec;
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__u64 addr;
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__u64 size;
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__u32 nr_pages_per_call;
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__u32 flags;
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__u64 expansion[10]; /* For future use */
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};
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static int __gup_benchmark_ioctl(unsigned int cmd,
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struct gup_benchmark *gup)
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{
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ktime_t start_time, end_time;
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unsigned long i, nr_pages, addr, next;
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int nr;
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struct page **pages;
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if (gup->size > ULONG_MAX)
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return -EINVAL;
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nr_pages = gup->size / PAGE_SIZE;
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pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
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if (!pages)
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return -ENOMEM;
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i = 0;
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nr = gup->nr_pages_per_call;
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start_time = ktime_get();
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for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
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if (nr != gup->nr_pages_per_call)
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break;
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next = addr + nr * PAGE_SIZE;
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if (next > gup->addr + gup->size) {
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next = gup->addr + gup->size;
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nr = (next - addr) / PAGE_SIZE;
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}
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switch (cmd) {
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case GUP_FAST_BENCHMARK:
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nr = get_user_pages_fast(addr, nr, gup->flags & 1,
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pages + i);
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break;
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case GUP_LONGTERM_BENCHMARK:
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nr = get_user_pages_longterm(addr, nr, gup->flags & 1,
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pages + i, NULL);
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break;
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case GUP_BENCHMARK:
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nr = get_user_pages(addr, nr, gup->flags & 1, pages + i,
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NULL);
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break;
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default:
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return -1;
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}
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if (nr <= 0)
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break;
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i += nr;
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}
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end_time = ktime_get();
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gup->get_delta_usec = ktime_us_delta(end_time, start_time);
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gup->size = addr - gup->addr;
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start_time = ktime_get();
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for (i = 0; i < nr_pages; i++) {
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if (!pages[i])
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break;
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put_page(pages[i]);
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}
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end_time = ktime_get();
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gup->put_delta_usec = ktime_us_delta(end_time, start_time);
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kvfree(pages);
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return 0;
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}
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static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
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unsigned long arg)
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{
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struct gup_benchmark gup;
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int ret;
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switch (cmd) {
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case GUP_FAST_BENCHMARK:
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case GUP_LONGTERM_BENCHMARK:
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case GUP_BENCHMARK:
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break;
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default:
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return -EINVAL;
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}
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if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
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return -EFAULT;
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ret = __gup_benchmark_ioctl(cmd, &gup);
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if (ret)
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return ret;
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if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
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return -EFAULT;
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return 0;
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}
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static const struct file_operations gup_benchmark_fops = {
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.open = nonseekable_open,
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.unlocked_ioctl = gup_benchmark_ioctl,
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};
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static int gup_benchmark_init(void)
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{
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debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
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&gup_benchmark_fops);
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return 0;
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}
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late_initcall(gup_benchmark_init);
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