mm cleanup: split out mincore() system call from filemap.c

diff --git a/mm/Makefile b/mm/Makefile
index b1f5cbcf22d2417395b6d29d38b3ce3e98275676..5ad80b427103b268e70900f38bc957ff5b8a2ee7 100644 (file)
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -14,6 +14,6 @@ export-objs := shmem.o filemap.o mempool.o page_alloc.o
 obj-y   := memory.o mmap.o filemap.o mprotect.o mlock.o mremap.o \
            vmalloc.o slab.o bootmem.o swap.o vmscan.o page_io.o \
            page_alloc.o swap_state.o swapfile.o numa.o oom_kill.o \
-           shmem.o highmem.o mempool.o msync.o
+           shmem.o highmem.o mempool.o msync.o mincore.o
 
 include $(TOPDIR)/Rules.make

diff --git a/mm/filemap.c b/mm/filemap.c
index 2518e0f508276118f42287263dae01b05389ffd8..9681f6d3e92cb6c3bd7812b67e92099eb5f8bfd2 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2455,160 +2455,6 @@ out:
        return error;
 }
 
-/*
- * 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_dentry->d_inode->i_mapping;
-       struct page * page, ** hash = page_hash(as, pgoff);
-
-       spin_lock(&pagecache_lock);
-       page = __find_page_nolock(as, pgoff, *hash);
-       if ((page) && (Page_Uptodate(page)))
-               present = 1;
-       spin_unlock(&pagecache_lock);
-
-       return present;
-}
-
-static long mincore_vma(struct vm_area_struct * vma,
-       unsigned long start, unsigned long end, unsigned char * 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,
- *             or len has a nonpositive value
- *  -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 * vec)
-{
-       int index = 0;
-       unsigned long end;
-       struct vm_area_struct * vma;
-       int unmapped_error = 0;
-       long error = -EINVAL;
-
-       down_read(&current->mm->mmap_sem);
-
-       if (start & ~PAGE_CACHE_MASK)
-               goto out;
-       len = (len + ~PAGE_CACHE_MASK) & PAGE_CACHE_MASK;
-       end = start + len;
-       if (end < start)
-               goto out;
-
-       error = 0;
-       if (end == start)
-               goto out;
-
-       /*
-        * If the interval [start,end) covers some unmapped address
-        * ranges, just ignore them, but return -ENOMEM at the end.
-        */
-       vma = find_vma(current->mm, start);
-       for (;;) {
-               /* Still start < end. */
-               error = -ENOMEM;
-               if (!vma)
-                       goto out;
-
-               /* 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;
-       }
-
-out:
-       up_read(&current->mm->mmap_sem);
-       return error;
-}
-
 static inline
 struct page *__read_cache_page(struct address_space *mapping,
                                unsigned long index,

diff --git a/mm/mincore.c b/mm/mincore.c
new file mode 100644 (file)
index 0000000..5209b8a
--- /dev/null
+++ b/mm/mincore.c
@@ -0,0 +1,175 @@
+/*
+ *     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 <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.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_dentry->d_inode->i_mapping;
+       struct page * page, ** hash = page_hash(as, pgoff);
+
+       page = __find_get_page(as, pgoff, hash);
+       if (page) {
+               present = Page_Uptodate(page);
+               page_cache_release(page);
+       }
+
+       return present;
+}
+
+static long mincore_vma(struct vm_area_struct * vma,
+       unsigned long start, unsigned long end, unsigned char * 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,
+ *             or len has a nonpositive value
+ *  -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 * vec)
+{
+       int index = 0;
+       unsigned long end;
+       struct vm_area_struct * vma;
+       int unmapped_error = 0;
+       long error = -EINVAL;
+
+       down_read(&current->mm->mmap_sem);
+
+       if (start & ~PAGE_CACHE_MASK)
+               goto out;
+       len = (len + ~PAGE_CACHE_MASK) & PAGE_CACHE_MASK;
+       end = start + len;
+       if (end < start)
+               goto out;
+
+       error = -EFAULT;
+       if (!access_ok(VERIFY_WRITE, (unsigned long) vec, len >> PAGE_SHIFT))
+               goto out;
+
+       error = 0;
+       if (end == start)
+               goto out;
+
+       /*
+        * If the interval [start,end) covers some unmapped address
+        * ranges, just ignore them, but return -ENOMEM at the end.
+        */
+       vma = find_vma(current->mm, start);
+       for (;;) {
+               /* Still start < end. */
+               error = -ENOMEM;
+               if (!vma)
+                       goto out;
+
+               /* 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;
+       }
+
+out:
+       up_read(&current->mm->mmap_sem);
+       return error;
+}