X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=mm%2Ffilemap_xip.c;h=65ffc321f0c0f223e4c6115e91c53d12d8319399;hb=f057eac0d7ad967138390a9dd7fd8267e1e39d19;hp=9dd9fbb7513947227d184c10c60cd2b731779ea8;hpb=5331be090567d9335476f876b2d85427cd7c4426;p=mv-sheeva.git

diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 9dd9fbb7513..65ffc321f0c 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -13,9 +13,33 @@
 #include <linux/module.h>
 #include <linux/uio.h>
 #include <linux/rmap.h>
+#include <linux/sched.h>
 #include <asm/tlbflush.h>
 #include "filemap.h"
 
+/*
+ * We do use our own empty page to avoid interference with other users
+ * of ZERO_PAGE(), such as /dev/zero
+ */
+static struct page *__xip_sparse_page;
+
+static struct page *xip_sparse_page(void)
+{
+	if (!__xip_sparse_page) {
+		unsigned long zeroes = get_zeroed_page(GFP_HIGHUSER);
+		if (zeroes) {
+			static DEFINE_SPINLOCK(xip_alloc_lock);
+			spin_lock(&xip_alloc_lock);
+			if (!__xip_sparse_page)
+				__xip_sparse_page = virt_to_page(zeroes);
+			else
+				free_page(zeroes);
+			spin_unlock(&xip_alloc_lock);
+		}
+	}
+	return __xip_sparse_page;
+}
+
 /*
  * This is a file read routine for execute in place files, and uses
  * the mapping->a_ops->get_xip_page() function for the actual low-level
@@ -135,34 +159,12 @@ xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
 }
 EXPORT_SYMBOL_GPL(xip_file_read);
 
-ssize_t
-xip_file_sendfile(struct file *in_file, loff_t *ppos,
-	     size_t count, read_actor_t actor, void *target)
-{
-	read_descriptor_t desc;
-
-	if (!count)
-		return 0;
-
-	desc.written = 0;
-	desc.count = count;
-	desc.arg.data = target;
-	desc.error = 0;
-
-	do_xip_mapping_read(in_file->f_mapping, &in_file->f_ra, in_file,
-			    ppos, &desc, actor);
-	if (desc.written)
-		return desc.written;
-	return desc.error;
-}
-EXPORT_SYMBOL_GPL(xip_file_sendfile);
-
 /*
  * __xip_unmap is invoked from xip_unmap and
  * xip_write
  *
  * This function walks all vmas of the address_space and unmaps the
- * ZERO_PAGE when found at pgoff. Should it go in rmap.c?
+ * __xip_sparse_page when found at pgoff.
  */
 static void
 __xip_unmap (struct address_space * mapping,
@@ -177,13 +179,16 @@ __xip_unmap (struct address_space * mapping,
 	spinlock_t *ptl;
 	struct page *page;
 
+	page = __xip_sparse_page;
+	if (!page)
+		return;
+
 	spin_lock(&mapping->i_mmap_lock);
 	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
 		mm = vma->vm_mm;
 		address = vma->vm_start +
 			((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
 		BUG_ON(address < vma->vm_start || address >= vma->vm_end);
-		page = ZERO_PAGE(0);
 		pte = page_check_address(page, mm, address, &ptl);
 		if (pte) {
 			/* Nuke the page table entry. */
@@ -222,16 +227,14 @@ xip_file_nopage(struct vm_area_struct * area,
 		+ area->vm_pgoff;
 
 	size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-	if (pgoff >= size) {
-		return NULL;
-	}
+	if (pgoff >= size)
+		return NOPAGE_SIGBUS;
 
 	page = mapping->a_ops->get_xip_page(mapping, pgoff*(PAGE_SIZE/512), 0);
-	if (!IS_ERR(page)) {
+	if (!IS_ERR(page))
 		goto out;
-	}
 	if (PTR_ERR(page) != -ENODATA)
-		return NULL;
+		return NOPAGE_SIGBUS;
 
 	/* sparse block */
 	if ((area->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
@@ -241,12 +244,14 @@ xip_file_nopage(struct vm_area_struct * area,
 		page = mapping->a_ops->get_xip_page (mapping,
 			pgoff*(PAGE_SIZE/512), 1);
 		if (IS_ERR(page))
-			return NULL;
+			return NOPAGE_SIGBUS;
 		/* unmap page at pgoff from all other vmas */
 		__xip_unmap(mapping, pgoff);
 	} else {
-		/* not shared and writable, use ZERO_PAGE() */
-		page = ZERO_PAGE(0);
+		/* not shared and writable, use xip_sparse_page() */
+		page = xip_sparse_page();
+		if (!page)
+			return NOPAGE_OOM;
 	}
 
 out:
@@ -408,7 +413,6 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
 	unsigned blocksize;
 	unsigned length;
 	struct page *page;
-	void *kaddr;
 
 	BUG_ON(!mapping->a_ops->get_xip_page);
 
@@ -432,11 +436,7 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
 		else
 			return PTR_ERR(page);
 	}
-	kaddr = kmap_atomic(page, KM_USER0);
-	memset(kaddr + offset, 0, length);
-	kunmap_atomic(kaddr, KM_USER0);
-
-	flush_dcache_page(page);
+	zero_user_page(page, offset, length, KM_USER0);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(xip_truncate_page);