1 files changed, 44 insertions, 92 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index b6aae2b33393..fcd19d323f9f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -27,6 +27,7 @@
 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/xattr.h>
+#include <linux/exportfs.h>
 #include <linux/generic_acl.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
@@ -82,6 +83,7 @@ enum sgp_type {
 	SGP_READ,	/* don't exceed i_size, don't allocate page */
 	SGP_CACHE,	/* don't exceed i_size, may allocate page */
 	SGP_WRITE,	/* may exceed i_size, may allocate page */
+	SGP_FAULT,	/* same as SGP_CACHE, return with page locked */
 };
 
 static int shmem_getpage(struct inode *inode, unsigned long idx,
@@ -93,8 +95,11 @@ static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
 	 * The above definition of ENTRIES_PER_PAGE, and the use of
 	 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
 	 * might be reconsidered if it ever diverges from PAGE_SIZE.
+	 *
+	 * __GFP_MOVABLE is masked out as swap vectors cannot move
 	 */
-	return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT);
+	return alloc_pages((gfp_mask & ~__GFP_MOVABLE) | __GFP_ZERO,
+				PAGE_CACHE_SHIFT-PAGE_SHIFT);
 }
 
 static inline void shmem_dir_free(struct page *page)
@@ -372,7 +377,7 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
 		}
 
 		spin_unlock(&info->lock);
-		page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO);
+		page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
 		if (page)
 			set_page_private(page, 0);
 		spin_lock(&info->lock);
@@ -1096,13 +1101,17 @@ static int shmem_getpage(struct inode *inode, unsigned long idx,
 
 	if (idx >= SHMEM_MAX_INDEX)
 		return -EFBIG;
+
+	if (type)
+		*type = 0;
+
 	/*
 	 * Normally, filepage is NULL on entry, and either found
 	 * uptodate immediately, or allocated and zeroed, or read
 	 * in under swappage, which is then assigned to filepage.
-	 * But shmem_prepare_write passes in a locked filepage,
-	 * which may be found not uptodate by other callers too,
-	 * and may need to be copied from the swappage read in.
+	 * But shmem_readpage and shmem_prepare_write pass in a locked
+	 * filepage, which may be found not uptodate by other callers
+	 * too, and may need to be copied from the swappage read in.
 	 */
 repeat:
 	if (!filepage)
@@ -1129,9 +1138,9 @@ repeat:
 		if (!swappage) {
 			shmem_swp_unmap(entry);
 			/* here we actually do the io */
-			if (type && *type == VM_FAULT_MINOR) {
+			if (type && !(*type & VM_FAULT_MAJOR)) {
 				__count_vm_event(PGMAJFAULT);
-				*type = VM_FAULT_MAJOR;
+				*type |= VM_FAULT_MAJOR;
 			}
 			spin_unlock(&info->lock);
 			swappage = shmem_swapin(info, swap, idx);
@@ -1285,8 +1294,10 @@ repeat:
 	}
 done:
 	if (*pagep != filepage) {
-		unlock_page(filepage);
 		*pagep = filepage;
+		if (sgp != SGP_FAULT)
+			unlock_page(filepage);
+
 	}
 	return 0;
 
@@ -1298,72 +1309,21 @@ failed:
 	return error;
 }
 
-static struct page *shmem_nopage(struct vm_area_struct *vma,
-				 unsigned long address, int *type)
+static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
-	struct page *page = NULL;
-	unsigned long idx;
 	int error;
+	int ret;
 
-	idx = (address - vma->vm_start) >> PAGE_SHIFT;
-	idx += vma->vm_pgoff;
-	idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
-	if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode))
-		return NOPAGE_SIGBUS;
+	if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+		return VM_FAULT_SIGBUS;
 
-	error = shmem_getpage(inode, idx, &page, SGP_CACHE, type);
+	error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_FAULT, &ret);
 	if (error)
-		return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS;
+		return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
 
-	mark_page_accessed(page);
-	return page;
-}
-
-static int shmem_populate(struct vm_area_struct *vma,
-	unsigned long addr, unsigned long len,
-	pgprot_t prot, unsigned long pgoff, int nonblock)
-{
-	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
-	struct mm_struct *mm = vma->vm_mm;
-	enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE;
-	unsigned long size;
-
-	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size)
-		return -EINVAL;
-
-	while ((long) len > 0) {
-		struct page *page = NULL;
-		int err;
-		/*
-		 * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE
-		 */
-		err = shmem_getpage(inode, pgoff, &page, sgp, NULL);
-		if (err)
-			return err;
-		/* Page may still be null, but only if nonblock was set. */
-		if (page) {
-			mark_page_accessed(page);
-			err = install_page(mm, vma, addr, page, prot);
-			if (err) {
-				page_cache_release(page);
-				return err;
-			}
-		} else if (vma->vm_flags & VM_NONLINEAR) {
-			/* No page was found just because we can't read it in
-			 * now (being here implies nonblock != 0), but the page
-			 * may exist, so set the PTE to fault it in later. */
-    			err = install_file_pte(mm, vma, addr, pgoff, prot);
-			if (err)
-	    			return err;
-		}
-
-		len -= PAGE_SIZE;
-		addr += PAGE_SIZE;
-		pgoff++;
-	}
-	return 0;
+	mark_page_accessed(vmf->page);
+	return ret | VM_FAULT_LOCKED;
 }
 
 #ifdef CONFIG_NUMA
@@ -1410,6 +1370,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	file_accessed(file);
 	vma->vm_ops = &shmem_vm_ops;
+	vma->vm_flags |= VM_CAN_NONLINEAR;
 	return 0;
 }
 
@@ -1485,9 +1446,18 @@ static const struct inode_operations shmem_symlink_inode_operations;
 static const struct inode_operations shmem_symlink_inline_operations;
 
 /*
- * Normally tmpfs makes no use of shmem_prepare_write, but it
- * lets a tmpfs file be used read-write below the loop driver.
+ * Normally tmpfs avoids the use of shmem_readpage and shmem_prepare_write;
+ * but providing them allows a tmpfs file to be used for splice, sendfile, and
+ * below the loop driver, in the generic fashion that many filesystems support.
  */
+static int shmem_readpage(struct file *file, struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL);
+	unlock_page(page);
+	return error;
+}
+
 static int
 shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
 {
@@ -1711,25 +1681,6 @@ static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count
 	return desc.error;
 }
 
-static ssize_t shmem_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_shmem_file_read(in_file, ppos, &desc, actor);
-	if (desc.written)
-		return desc.written;
-	return desc.error;
-}
-
 static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
@@ -2371,7 +2322,7 @@ static int init_inodecache(void)
 {
 	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
 				sizeof(struct shmem_inode_info),
-				0, 0, init_once, NULL);
+				0, 0, init_once);
 	if (shmem_inode_cachep == NULL)
 		return -ENOMEM;
 	return 0;
@@ -2386,6 +2337,7 @@ static const struct address_space_operations shmem_aops = {
 	.writepage	= shmem_writepage,
 	.set_page_dirty	= __set_page_dirty_no_writeback,
 #ifdef CONFIG_TMPFS
+	.readpage	= shmem_readpage,
 	.prepare_write	= shmem_prepare_write,
 	.commit_write	= simple_commit_write,
 #endif
@@ -2399,7 +2351,8 @@ static const struct file_operations shmem_file_operations = {
 	.read		= shmem_file_read,
 	.write		= shmem_file_write,
 	.fsync		= simple_sync_file,
-	.sendfile	= shmem_file_sendfile,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= generic_file_splice_write,
 #endif
 };
 
@@ -2463,8 +2416,7 @@ static const struct super_operations shmem_ops = {
 };
 
 static struct vm_operations_struct shmem_vm_ops = {
-	.nopage		= shmem_nopage,
-	.populate	= shmem_populate,
+	.fault		= shmem_fault,
 #ifdef CONFIG_NUMA
 	.set_policy     = shmem_set_policy,
 	.get_policy     = shmem_get_policy,