Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 191 insertions, 0 deletions

diff --git a/mm/mincore.c b/mm/mincore.c
new file mode 100644
index 0000000..07833dc
--- /dev/null
+++ b/mm/mincore.c
@@ -0,0 +1,191 @@
+/*
+ *	linux/mm/mincore.c
+ *
+ * Copyright (C) 1994-1999  Linus Torvalds
+ */
+
+/*
+ * The mincore() system call.
+ */
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/syscalls.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+
+/*
+ * Later we can get more picky about what "in core" means precisely.
+ * For now, simply check to see if the page is in the page cache,
+ * and is up to date; i.e. that no page-in operation would be required
+ * at this time if an application were to map and access this page.
+ */
+static unsigned char mincore_page(struct vm_area_struct * vma,
+	unsigned long pgoff)
+{
+	unsigned char present = 0;
+	struct address_space * as = vma->vm_file->f_mapping;
+	struct page * page;
+
+	page = find_get_page(as, pgoff);
+	if (page) {
+		present = PageUptodate(page);
+		page_cache_release(page);
+	}
+
+	return present;
+}
+
+static long mincore_vma(struct vm_area_struct * vma,
+	unsigned long start, unsigned long end, unsigned char __user * vec)
+{
+	long error, i, remaining;
+	unsigned char * tmp;
+
+	error = -ENOMEM;
+	if (!vma->vm_file)
+		return error;
+
+	start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+	if (end > vma->vm_end)
+		end = vma->vm_end;
+	end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+
+	error = -EAGAIN;
+	tmp = (unsigned char *) __get_free_page(GFP_KERNEL);
+	if (!tmp)
+		return error;
+
+	/* (end - start) is # of pages, and also # of bytes in "vec */
+	remaining = (end - start),
+
+	error = 0;
+	for (i = 0; remaining > 0; remaining -= PAGE_SIZE, i++) {
+		int j = 0;
+		long thispiece = (remaining < PAGE_SIZE) ?
+						remaining : PAGE_SIZE;
+
+		while (j < thispiece)
+			tmp[j++] = mincore_page(vma, start++);
+
+		if (copy_to_user(vec + PAGE_SIZE * i, tmp, thispiece)) {
+			error = -EFAULT;
+			break;
+		}
+	}
+
+	free_page((unsigned long) tmp);
+	return error;
+}
+
+/*
+ * The mincore(2) system call.
+ *
+ * mincore() returns the memory residency status of the pages in the
+ * current process's address space specified by [addr, addr + len).
+ * The status is returned in a vector of bytes.  The least significant
+ * bit of each byte is 1 if the referenced page is in memory, otherwise
+ * it is zero.
+ *
+ * Because the status of a page can change after mincore() checks it
+ * but before it returns to the application, the returned vector may
+ * contain stale information.  Only locked pages are guaranteed to
+ * remain in memory.
+ *
+ * return values:
+ *  zero    - success
+ *  -EFAULT - vec points to an illegal address
+ *  -EINVAL - addr is not a multiple of PAGE_CACHE_SIZE
+ *  -ENOMEM - Addresses in the range [addr, addr + len] are
+ *		invalid for the address space of this process, or
+ *		specify one or more pages which are not currently
+ *		mapped
+ *  -EAGAIN - A kernel resource was temporarily unavailable.
+ */
+asmlinkage long sys_mincore(unsigned long start, size_t len,
+	unsigned char __user * vec)
+{
+	int index = 0;
+	unsigned long end, limit;
+	struct vm_area_struct * vma;
+	size_t max;
+	int unmapped_error = 0;
+	long error;
+
+	/* check the arguments */
+ 	if (start & ~PAGE_CACHE_MASK)
+		goto einval;
+
+	if (start < FIRST_USER_PGD_NR * PGDIR_SIZE)
+		goto enomem;
+
+	limit = TASK_SIZE;
+	if (start >= limit)
+		goto enomem;
+
+	if (!len)
+		return 0;
+
+	max = limit - start;
+	len = PAGE_CACHE_ALIGN(len);
+	if (len > max || !len)
+		goto enomem;
+
+	end = start + len;
+
+	/* check the output buffer whilst holding the lock */
+	error = -EFAULT;
+	down_read(&current->mm->mmap_sem);
+
+	if (!access_ok(VERIFY_WRITE, vec, len >> PAGE_SHIFT))
+		goto out;
+
+	/*
+	 * If the interval [start,end) covers some unmapped address
+	 * ranges, just ignore them, but return -ENOMEM at the end.
+	 */
+	error = 0;
+
+	vma = find_vma(current->mm, start);
+	while (vma) {
+		/* Here start < vma->vm_end. */
+		if (start < vma->vm_start) {
+			unmapped_error = -ENOMEM;
+			start = vma->vm_start;
+		}
+
+		/* Here vma->vm_start <= start < vma->vm_end. */
+		if (end <= vma->vm_end) {
+			if (start < end) {
+				error = mincore_vma(vma, start, end,
+							&vec[index]);
+				if (error)
+					goto out;
+			}
+			error = unmapped_error;
+			goto out;
+		}
+
+		/* Here vma->vm_start <= start < vma->vm_end < end. */
+		error = mincore_vma(vma, start, vma->vm_end, &vec[index]);
+		if (error)
+			goto out;
+		index += (vma->vm_end - start) >> PAGE_CACHE_SHIFT;
+		start = vma->vm_end;
+		vma = vma->vm_next;
+	}
+
+	/* we found a hole in the area queried if we arrive here */
+	error = -ENOMEM;
+
+out:
+	up_read(&current->mm->mmap_sem);
+	return error;
+
+einval:
+	return -EINVAL;
+enomem:
+	return -ENOMEM;
+}