don't put symlink bodies in pagecache into highmem

kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.

new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases.  page_follow_link_light()
instrumented to yell about anything missed.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/filesystems/porting

@@ -504,3 +504,8 @@ in your dentry operations instead.
 [mandatory]
 	__fd_install() & fd_install() can now sleep. Callers should not
 	hold a spinlock	or other resources that do not allow a schedule.
+--
+[mandatory]
+	any symlink that might use page_follow_link_light/page_put_link() must
+	have inode_nohighmem(inode) called before anything might start playing with
+	its pagecache.

fs/affs/inode.c

@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)
 		break;
 	case ST_SOFTLINK:
 		inode->i_mode |= S_IFLNK;
+		inode_nohighmem(inode);
 		inode->i_op = &affs_symlink_inode_operations;
 		inode->i_data.a_ops = &affs_symlink_aops;
 		break;

fs/affs/namei.c

@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 		return -ENOSPC;
 
 	inode->i_op = &affs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_data.a_ops = &affs_symlink_aops;
 	inode->i_mode = S_IFLNK | 0777;
 	mode_to_prot(inode);

fs/affs/symlink.c

@@ -14,7 +14,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
 {
 	struct buffer_head *bh;
 	struct inode *inode = page->mapping->host;
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct slink_front *lf;
 	int			 i, j;
 	char			 c;
@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
 	link[i] = '\0';
 	affs_brelse(bh);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

fs/afs/inode.c

@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
 	case AFS_FTYPE_SYMLINK:
 		inode->i_mode	= S_IFLNK | vnode->status.mode;
 		inode->i_op	= &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		break;
 	default:
 		printk("kAFS: AFS vnode with undefined type\n");

fs/befs/linuxvfs.c

@@ -397,6 +397,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &befs_symlink_aops;
 		} else {
 			inode->i_link = befs_ino->i_data.symlink;
@@ -469,7 +470,7 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)
 	struct befs_inode_info *befs_ino = BEFS_I(inode);
 	befs_data_stream *data = &befs_ino->i_data.ds;
 	befs_off_t len = data->size;
-	char *link = kmap(page);
+	char *link = page_address(page);
 
 	if (len == 0 || len > PAGE_SIZE) {
 		befs_error(sb, "Long symlink with illegal length");
@@ -483,12 +484,10 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)
 	}
 	link[len - 1] = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

fs/btrfs/inode.c

@@ -3774,6 +3774,7 @@ static void btrfs_read_locked_inode(struct inode *inode)
 		break;
 	case S_IFLNK:
 		inode->i_op = &btrfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &btrfs_symlink_aops;
 		break;
 	default:
@@ -9705,6 +9706,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 	btrfs_free_path(path);
 
 	inode->i_op = &btrfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &btrfs_symlink_aops;
 	inode_set_bytes(inode, name_len);
 	btrfs_i_size_write(inode, name_len);

fs/coda/cnode.c

@@ -8,6 +8,7 @@
 
 #include <linux/coda.h>
 #include <linux/coda_psdev.h>
+#include <linux/pagemap.h>
 #include "coda_linux.h"
 
 static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
@@ -35,6 +36,7 @@ static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
                 inode->i_fop = &coda_dir_operations;
         } else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &coda_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &coda_symlink_aops;
 		inode->i_mapping = &inode->i_data;
 	} else

fs/coda/symlink.c

@@ -26,7 +26,7 @@ static int coda_symlink_filler(struct file *file, struct page *page)
 	int error;
 	struct coda_inode_info *cii;
 	unsigned int len = PAGE_SIZE;
-	char *p = kmap(page);
+	char *p = page_address(page);
 
 	cii = ITOC(inode);
 
@@ -34,13 +34,11 @@ static int coda_symlink_filler(struct file *file, struct page *page)
 	if (error)
 		goto fail;
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return error;
 }

fs/cramfs/inode.c

@@ -100,6 +100,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
 		break;
 	case S_IFLNK:
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &cramfs_aops;
 		break;
 	default:

fs/efs/inode.c

@@ -151,6 +151,7 @@ struct inode *efs_iget(struct super_block *super, unsigned long ino)
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_data.a_ops = &efs_symlink_aops;
 			break;
 		case S_IFCHR:

fs/efs/symlink.c

@@ -13,7 +13,7 @@
 
 static int efs_symlink_readpage(struct file *file, struct page *page)
 {
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct buffer_head * bh;
 	struct inode * inode = page->mapping->host;
 	efs_block_t size = inode->i_size;
@@ -39,12 +39,10 @@ static int efs_symlink_readpage(struct file *file, struct page *page)
 	}
 	link[size] = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

fs/exofs/inode.c

@@ -1227,6 +1227,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
 			inode->i_link = (char *)oi->i_data;
 		} else {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &exofs_aops;
 		}
 	} else {

fs/exofs/namei.c

@@ -111,6 +111,7 @@ static int exofs_symlink(struct inode *dir, struct dentry *dentry,
 	if (l > sizeof(oi->i_data)) {
 		/* slow symlink */
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &exofs_aops;
 		memset(oi->i_data, 0, sizeof(oi->i_data));
 

fs/ext2/inode.c

@@ -1420,6 +1420,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 				sizeof(ei->i_data) - 1);
 		} else {
 			inode->i_op = &ext2_symlink_inode_operations;
+			inode_nohighmem(inode);
 			if (test_opt(inode->i_sb, NOBH))
 				inode->i_mapping->a_ops = &ext2_nobh_aops;
 			else

fs/ext2/namei.c

@@ -183,6 +183,7 @@ static int ext2_symlink (struct inode * dir, struct dentry * dentry,
 	if (l > sizeof (EXT2_I(inode)->i_data)) {
 		/* slow symlink */
 		inode->i_op = &ext2_symlink_inode_operations;
+		inode_nohighmem(inode);
 		if (test_opt(inode->i_sb, NOBH))
 			inode->i_mapping->a_ops = &ext2_nobh_aops;
 		else

fs/ext4/inode.c

@@ -4283,6 +4283,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 			inode->i_op = &ext4_symlink_inode_operations;
 			ext4_set_aops(inode);
 		}
+		inode_nohighmem(inode);
 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 		inode->i_op = &ext4_special_inode_operations;

fs/ext4/namei.c

@@ -3132,6 +3132,7 @@ static int ext4_symlink(struct inode *dir,
 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
 		if (!encryption_required)
 			inode->i_op = &ext4_symlink_inode_operations;
+		inode_nohighmem(inode);
 		ext4_set_aops(inode);
 		/*
 		 * We cannot call page_symlink() with transaction started

fs/ext4/symlink.c

@@ -45,7 +45,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook
 		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 		if (IS_ERR(cpage))
 			return ERR_CAST(cpage);
-		caddr = kmap(cpage);
+		caddr = page_address(cpage);
 		caddr[size] = 0;
 	}
 
@@ -75,16 +75,12 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Null-terminate the name */
 	if (res <= plen)
 		paddr[res] = '\0';
-	if (cpage) {
-		kunmap(cpage);
+	if (cpage)
 		page_cache_release(cpage);
-	}
 	return *cookie = paddr;
 errout:
-	if (cpage) {
-		kunmap(cpage);
+	if (cpage)
 		page_cache_release(cpage);
-	}
 	kfree(paddr);
 	return ERR_PTR(res);
 }

fs/f2fs/inode.c

@@ -202,6 +202,7 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 			inode->i_op = &f2fs_encrypted_symlink_inode_operations;
 		else
 			inode->i_op = &f2fs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &f2fs_dblock_aops;
 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {

fs/f2fs/namei.c

@@ -351,6 +351,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 		inode->i_op = &f2fs_encrypted_symlink_inode_operations;
 	else
 		inode->i_op = &f2fs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &f2fs_dblock_aops;
 
 	f2fs_lock_op(sbi);
@@ -942,7 +943,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 	if (IS_ERR(cpage))
 		return ERR_CAST(cpage);
-	caddr = kmap(cpage);
+	caddr = page_address(cpage);
 	caddr[size] = 0;
 
 	/* Symlink is encrypted */
@@ -982,13 +983,11 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Null-terminate the name */
 	paddr[res] = '\0';
 
-	kunmap(cpage);
 	page_cache_release(cpage);
 	return *cookie = paddr;
 errout:
 	kfree(cstr.name);
 	f2fs_fname_crypto_free_buffer(&pstr);
-	kunmap(cpage);
 	page_cache_release(cpage);
 	return ERR_PTR(res);
 }

fs/freevxfs/vxfs_inode.c

@@ -326,6 +326,7 @@ vxfs_iget(struct super_block *sbp, ino_t ino)
 	} else if (S_ISLNK(ip->i_mode)) {
 		if (!VXFS_ISIMMED(vip)) {
 			ip->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(ip);
 			ip->i_mapping->a_ops = &vxfs_aops;
 		} else {
 			ip->i_op = &simple_symlink_inode_operations;

fs/hfsplus/inode.c

@@ -403,6 +403,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode)
 	} else if (S_ISLNK(inode->i_mode)) {
 		sbi->file_count++;
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &hfsplus_aops;
 		hip->clump_blocks = 1;
 	} else
@@ -526,6 +527,7 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd)
 			inode->i_mapping->a_ops = &hfsplus_aops;
 		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &hfsplus_aops;
 		} else {
 			init_special_inode(inode, inode->i_mode,

fs/hpfs/inode.c

@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)
 			kfree(ea);
 			i->i_mode = S_IFLNK | 0777;
 			i->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(i);
 			i->i_data.a_ops = &hpfs_symlink_aops;
 			set_nlink(i, 1);
 			i->i_size = ea_size;

fs/hpfs/namei.c

@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy
 	result->i_blocks = 1;
 	set_nlink(result, 1);
 	result->i_size = strlen(symlink);
+	inode_nohighmem(result);
 	result->i_op = &page_symlink_inode_operations;
 	result->i_data.a_ops = &hpfs_symlink_aops;
 
@@ -500,7 +501,7 @@ static int hpfs_rmdir(struct inode *dir, struct dentry *dentry)
 
 static int hpfs_symlink_readpage(struct file *file, struct page *page)
 {
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct inode *i = page->mapping->host;
 	struct fnode *fnode;
 	struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page)
 		goto fail;
 	hpfs_unlock(i->i_sb);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
 fail:
 	hpfs_unlock(i->i_sb);
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

fs/hugetlbfs/inode.c

@@ -760,6 +760,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			break;
 		}
 		lockdep_annotate_inode_mutex_key(inode);

fs/inode.c

@@ -2028,3 +2028,9 @@ void inode_set_flags(struct inode *inode, unsigned int flags,
 				  new_flags) != old_flags));
 }
 EXPORT_SYMBOL(inode_set_flags);
+
+void inode_nohighmem(struct inode *inode)
+{
+	mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
+}
+EXPORT_SYMBOL(inode_nohighmem);

fs/isofs/inode.c

@@ -1417,6 +1417,7 @@ static int isofs_read_inode(struct inode *inode, int relocated)
 		inode->i_fop = &isofs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &isofs_symlink_aops;
 	} else
 		/* XXX - parse_rock_ridge_inode() had already set i_rdev. */

fs/isofs/rock.c

@@ -687,7 +687,7 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 	struct inode *inode = page->mapping->host;
 	struct iso_inode_info *ei = ISOFS_I(inode);
 	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
-	char *link = kmap(page);
+	char *link = page_address(page);
 	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 	struct buffer_head *bh;
 	char *rpnt = link;
@@ -774,7 +774,6 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 	brelse(bh);
 	*rpnt = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
@@ -791,7 +790,6 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 	brelse(bh);
 error:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

fs/jfs/inode.c

@@ -60,6 +60,7 @@ struct inode *jfs_iget(struct super_block *sb, unsigned long ino)
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (inode->i_size >= IDATASIZE) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &jfs_aops;
 		} else {
 			inode->i_op = &jfs_fast_symlink_inode_operations;

fs/jfs/namei.c

@@ -983,6 +983,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,
 		jfs_info("jfs_symlink: allocate extent ip:0x%p", ip);
 
 		ip->i_op = &jfs_symlink_inode_operations;
+		inode_nohighmem(ip);
 		ip->i_mapping->a_ops = &jfs_aops;
 
 		/*

fs/logfs/dir.c

@@ -529,6 +529,7 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,
 		return PTR_ERR(inode);
 
 	inode->i_op = &page_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &logfs_reg_aops;
 
 	return __logfs_create(dir, dentry, inode, target, destlen);

fs/logfs/inode.c

@@ -65,6 +65,7 @@ static void logfs_inode_setops(struct inode *inode)
 		break;
 	case S_IFLNK:
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &logfs_reg_aops;
 		break;
 	case S_IFSOCK:	/* fall through */

fs/minix/inode.c

@@ -452,6 +452,7 @@ void minix_set_inode(struct inode *inode, dev_t rdev)
 		inode->i_mapping->a_ops = &minix_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &minix_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &minix_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);

fs/namei.c

@@ -4527,7 +4527,8 @@ static const char *page_getlink(struct dentry * dentry, void **cookie)
 	if (IS_ERR(page))
 		return (char*)page;
 	*cookie = page;
-	kaddr = kmap(page);
+	BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
+	kaddr = page_address(page);
 	nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
 	return kaddr;
 }
@@ -4541,7 +4542,6 @@ EXPORT_SYMBOL(page_follow_link_light);
 void page_put_link(struct inode *unused, void *cookie)
 {
 	struct page *page = cookie;
-	kunmap(page);
 	page_cache_release(page);
 }
 EXPORT_SYMBOL(page_put_link);
@@ -4565,7 +4565,6 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
 	struct page *page;
 	void *fsdata;
 	int err;
-	char *kaddr;
 	unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE;
 	if (nofs)
 		flags |= AOP_FLAG_NOFS;
@@ -4576,9 +4575,7 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
 	if (err)
 		goto fail;
 
-	kaddr = kmap_atomic(page);
-	memcpy(kaddr, symname, len-1);
-	kunmap_atomic(kaddr);
+	memcpy(page_address(page), symname, len-1);
 
 	err = pagecache_write_end(NULL, mapping, 0, len-1, len-1,
 							page, fsdata);

fs/ncpfs/inode.c

@@ -283,6 +283,7 @@ ncp_iget(struct super_block *sb, struct ncp_entry_info *info)
 #if defined(CONFIG_NCPFS_EXTRAS) || defined(CONFIG_NCPFS_NFS_NS)
 		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &ncp_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_data.a_ops = &ncp_symlink_aops;
 #endif
 		} else {

fs/nfs/inode.c

@@ -408,9 +408,10 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st
 				inode->i_fop = NULL;
 				inode->i_flags |= S_AUTOMOUNT;
 			}
-		} else if (S_ISLNK(inode->i_mode))
+		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &nfs_symlink_inode_operations;
-		else
+			inode_nohighmem(inode);
+		} else
 			init_special_inode(inode, inode->i_mode, fattr->rdev);
 
 		memset(&inode->i_atime, 0, sizeof(inode->i_atime));

fs/nfs/symlink.c

@@ -56,7 +56,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)
 	if (IS_ERR(page))
 		return ERR_CAST(page);
 	*cookie = page;
-	return kmap(page);
+	return page_address(page);
 }
 
 /*

fs/nilfs2/inode.c

@@ -510,6 +510,7 @@ static int __nilfs_read_inode(struct super_block *sb,
 		inode->i_mapping->a_ops = &nilfs_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &nilfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &nilfs_aops;
 	} else {
 		inode->i_op = &nilfs_special_inode_operations;

fs/nilfs2/namei.c

@@ -161,6 +161,7 @@ static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 
 	/* slow symlink */
 	inode->i_op = &nilfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &nilfs_aops;
 	err = page_symlink(inode, symname, l);
 	if (err)

fs/ocfs2/inode.c

@@ -361,6 +361,7 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,
 		    break;
 	    case S_IFLNK:
 		    inode->i_op = &ocfs2_symlink_inode_operations;
+		    inode_nohighmem(inode);
 		    i_size_write(inode, le64_to_cpu(fe->i_size));
 		    break;
 	    default:

fs/ocfs2/namei.c

@@ -1960,6 +1960,7 @@ static int ocfs2_symlink(struct inode *dir,
 	inode->i_rdev = 0;
 	newsize = l - 1;
 	inode->i_op = &ocfs2_symlink_inode_operations;
+	inode_nohighmem(inode);
 	if (l > ocfs2_fast_symlink_chars(sb)) {
 		u32 offset = 0;
 

fs/qnx4/inode.c

@@ -316,6 +316,7 @@ struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 		inode->i_fop = &qnx4_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &qnx4_aops;
 		qnx4_i(inode)->mmu_private = inode->i_size;
 	} else {

fs/qnx6/inode.c

@@ -582,6 +582,7 @@ struct inode *qnx6_iget(struct super_block *sb, unsigned ino)
 		inode->i_mapping->a_ops = &qnx6_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &qnx6_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, 0);

fs/ramfs/inode.c

@@ -79,6 +79,7 @@ struct inode *ramfs_get_inode(struct super_block *sb,
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			break;
 		}
 	}

fs/reiserfs/inode.c

@@ -1361,6 +1361,7 @@ static void init_inode(struct inode *inode, struct treepath *path)
 		inode->i_fop = &reiserfs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &reiserfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &reiserfs_address_space_operations;
 	} else {
 		inode->i_blocks = 0;

fs/reiserfs/namei.c

@@ -1170,6 +1170,7 @@ static int reiserfs_symlink(struct inode *parent_dir,
 	reiserfs_update_inode_transaction(parent_dir);
 
 	inode->i_op = &reiserfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &reiserfs_address_space_operations;
 
 	retval = reiserfs_add_entry(&th, parent_dir, dentry->d_name.name,

fs/romfs/super.c

@@ -360,6 +360,7 @@ static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
 		break;
 	case ROMFH_SYM:
 		i->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(i);
 		i->i_data.a_ops = &romfs_aops;
 		mode |= S_IRWXUGO;
 		break;

fs/squashfs/inode.c

@@ -41,6 +41,7 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/xattr.h>
+#include <linux/pagemap.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
@@ -291,6 +292,7 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 		inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
 		inode->i_op = &squashfs_symlink_inode_ops;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &squashfs_symlink_aops;
 		inode->i_mode |= S_IFLNK;
 		squashfs_i(inode)->start = block;

fs/sysv/inode.c

@@ -163,6 +163,7 @@ void sysv_set_inode(struct inode *inode, dev_t rdev)
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &sysv_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);

fs/udf/inode.c

@@ -1541,6 +1541,7 @@ static int udf_read_inode(struct inode *inode, bool hidden_inode)
 	case ICBTAG_FILE_TYPE_SYMLINK:
 		inode->i_data.a_ops = &udf_symlink_aops;
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mode = S_IFLNK | S_IRWXUGO;
 		break;
 	case ICBTAG_FILE_TYPE_MAIN:

fs/udf/namei.c

@@ -922,6 +922,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
 
 	inode->i_data.a_ops = &udf_symlink_aops;
 	inode->i_op = &page_symlink_inode_operations;
+	inode_nohighmem(inode);
 
 	if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
 		struct kernel_lb_addr eloc;

fs/udf/symlink.c

@@ -107,7 +107,7 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 	struct buffer_head *bh = NULL;
 	unsigned char *symlink;
 	int err;
-	unsigned char *p = kmap(page);
+	unsigned char *p = page_address(page);
 	struct udf_inode_info *iinfo;
 	uint32_t pos;
 
@@ -141,7 +141,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 
 	up_read(&iinfo->i_data_sem);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
@@ -149,7 +148,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 	up_read(&iinfo->i_data_sem);
 	SetPageError(page);
 out_unmap:
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

fs/ufs/inode.c

@@ -533,6 +533,7 @@ static void ufs_set_inode_ops(struct inode *inode)
 		} else {
 			inode->i_mapping->a_ops = &ufs_aops;
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 		}
 	} else
 		init_special_inode(inode, inode->i_mode,

fs/ufs/namei.c

@@ -124,6 +124,7 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 	if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 		/* slow symlink */
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &ufs_aops;
 		err = page_symlink(inode, symname, l);
 		if (err)

include/linux/fs.h

@@ -3025,5 +3025,6 @@ static inline bool dir_relax(struct inode *inode)
 }
 
 extern bool path_noexec(const struct path *path);
+extern void inode_nohighmem(struct inode *inode);
 
 #endif /* _LINUX_FS_H */

mm/shmem.c

@@ -2444,7 +2444,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 	int len;
 	struct inode *inode;
 	struct page *page;
-	char *kaddr;
 	struct shmem_inode_info *info;
 
 	len = strlen(symname) + 1;
@@ -2483,9 +2482,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 		}
 		inode->i_mapping->a_ops = &shmem_aops;
 		inode->i_op = &shmem_symlink_inode_operations;
-		kaddr = kmap_atomic(page);
-		memcpy(kaddr, symname, len);
-		kunmap_atomic(kaddr);
+		inode_nohighmem(inode);
+		memcpy(page_address(page), symname, len);
 		SetPageUptodate(page);
 		set_page_dirty(page);
 		unlock_page(page);
@@ -2506,13 +2504,12 @@ static const char *shmem_follow_link(struct dentry *dentry, void **cookie)
 		return ERR_PTR(error);
 	unlock_page(page);
 	*cookie = page;
-	return kmap(page);
+	return page_address(page);
 }
 
 static void shmem_put_link(struct inode *unused, void *cookie)
 {
 	struct page *page = cookie;
-	kunmap(page);
 	mark_page_accessed(page);
 	page_cache_release(page);
 }