From 244b2c5ca8b14627e4a17755e5922221e121c771 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 09 Oct 2024 06:15:07 +0000
Subject: [PATCH] change system file

---
 kernel/mm/gup_benchmark.c |  136 ++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 120 insertions(+), 16 deletions(-)

diff --git a/kernel/mm/gup_benchmark.c b/kernel/mm/gup_benchmark.c
index 7e6f2d2..8b3e5b5 100644
--- a/kernel/mm/gup_benchmark.c
+++ b/kernel/mm/gup_benchmark.c
@@ -6,14 +6,63 @@
 #include <linux/debugfs.h>
 
 #define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)
+#define GUP_BENCHMARK		_IOWR('g', 2, struct gup_benchmark)
+#define PIN_FAST_BENCHMARK	_IOWR('g', 3, struct gup_benchmark)
+#define PIN_BENCHMARK		_IOWR('g', 4, struct gup_benchmark)
+#define PIN_LONGTERM_BENCHMARK	_IOWR('g', 5, struct gup_benchmark)
 
 struct gup_benchmark {
-	__u64 delta_usec;
+	__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_benchmark failure");
+				break;
+			}
+		}
+		break;
+	}
+}
 
 static int __gup_benchmark_ioctl(unsigned int cmd,
 		struct gup_benchmark *gup)
@@ -22,6 +71,9 @@
 	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;
@@ -30,6 +82,11 @@
 	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;
@@ -44,24 +101,67 @@
 			nr = (next - addr) / PAGE_SIZE;
 		}
 
-		nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i);
+		/* 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();
 
-	gup->delta_usec = ktime_us_delta(end_time, start_time);
+	/* 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;
 
-	for (i = 0; i < nr_pages; i++) {
-		if (!pages[i])
-			break;
-		put_page(pages[i]);
-	}
+	/*
+	 * 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 0;
+	return ret;
 }
 
 static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
@@ -70,8 +170,16 @@
 	struct gup_benchmark gup;
 	int ret;
 
-	if (cmd != GUP_FAST_BENCHMARK)
+	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;
@@ -93,12 +201,8 @@
 
 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");
+	debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
+				   &gup_benchmark_fops);
 
 	return 0;
 }

--
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