X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=mm%2Fsecretmem.c;h=d1986ce2e7c7790ae4df0112037b62afc74a02f1;hb=refs%2Fheads%2Fsandbox%2Fm.szyprowski%2Fvirgl;hp=1fea68b8d5a6f90d0b7f7e32ecabcf3ba556ebe7;hpb=d41adc4e22c62640fa7de93f713a3c5b3638ab2e;p=platform%2Fkernel%2Flinux-rpi.git

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 1fea68b..d1986ce 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -18,7 +18,6 @@
 #include <linux/secretmem.h>
 #include <linux/set_memory.h>
 #include <linux/sched/signal.h>
-#include <linux/refcount.h>
 
 #include <uapi/linux/magic.h>
 
@@ -41,11 +40,11 @@ module_param_named(enable, secretmem_enable, bool, 0400);
 MODULE_PARM_DESC(secretmem_enable,
 		 "Enable secretmem and memfd_secret(2) system call");
 
-static refcount_t secretmem_users;
+static atomic_t secretmem_users;
 
 bool secretmem_active(void)
 {
-	return !!refcount_read(&secretmem_users);
+	return !!atomic_read(&secretmem_users);
 }
 
 static vm_fault_t secretmem_fault(struct vm_fault *vmf)
@@ -56,22 +55,28 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf)
 	gfp_t gfp = vmf->gfp_mask;
 	unsigned long addr;
 	struct page *page;
+	vm_fault_t ret;
 	int err;
 
 	if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode))
 		return vmf_error(-EINVAL);
 
+	filemap_invalidate_lock_shared(mapping);
+
 retry:
 	page = find_lock_page(mapping, offset);
 	if (!page) {
 		page = alloc_page(gfp | __GFP_ZERO);
-		if (!page)
-			return VM_FAULT_OOM;
+		if (!page) {
+			ret = VM_FAULT_OOM;
+			goto out;
+		}
 
 		err = set_direct_map_invalid_noflush(page);
 		if (err) {
 			put_page(page);
-			return vmf_error(err);
+			ret = vmf_error(err);
+			goto out;
 		}
 
 		__SetPageUptodate(page);
@@ -87,7 +92,8 @@ retry:
 			if (err == -EEXIST)
 				goto retry;
 
-			return vmf_error(err);
+			ret = vmf_error(err);
+			goto out;
 		}
 
 		addr = (unsigned long)page_address(page);
@@ -95,7 +101,11 @@ retry:
 	}
 
 	vmf->page = page;
-	return VM_FAULT_LOCKED;
+	ret = VM_FAULT_LOCKED;
+
+out:
+	filemap_invalidate_unlock_shared(mapping);
+	return ret;
 }
 
 static const struct vm_operations_struct secretmem_vm_ops = {
@@ -104,7 +114,7 @@ static const struct vm_operations_struct secretmem_vm_ops = {
 
 static int secretmem_release(struct inode *inode, struct file *file)
 {
-	refcount_dec(&secretmem_users);
+	atomic_dec(&secretmem_users);
 	return 0;
 }
 
@@ -159,6 +169,30 @@ const struct address_space_operations secretmem_aops = {
 	.isolate_page	= secretmem_isolate_page,
 };
 
+static int secretmem_setattr(struct user_namespace *mnt_userns,
+			     struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = d_inode(dentry);
+	struct address_space *mapping = inode->i_mapping;
+	unsigned int ia_valid = iattr->ia_valid;
+	int ret;
+
+	filemap_invalidate_lock(mapping);
+
+	if ((ia_valid & ATTR_SIZE) && inode->i_size)
+		ret = -EINVAL;
+	else
+		ret = simple_setattr(mnt_userns, dentry, iattr);
+
+	filemap_invalidate_unlock(mapping);
+
+	return ret;
+}
+
+static const struct inode_operations secretmem_iops = {
+	.setattr = secretmem_setattr,
+};
+
 static struct vfsmount *secretmem_mnt;
 
 static struct file *secretmem_file_create(unsigned long flags)
@@ -178,6 +212,7 @@ static struct file *secretmem_file_create(unsigned long flags)
 	mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
 	mapping_set_unevictable(inode->i_mapping);
 
+	inode->i_op = &secretmem_iops;
 	inode->i_mapping->a_ops = &secretmem_aops;
 
 	/* pretend we are a normal file with zero size */
@@ -204,6 +239,8 @@ SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)
 
 	if (flags & ~(SECRETMEM_FLAGS_MASK | O_CLOEXEC))
 		return -EINVAL;
+	if (atomic_read(&secretmem_users) < 0)
+		return -ENFILE;
 
 	fd = get_unused_fd_flags(flags & O_CLOEXEC);
 	if (fd < 0)
@@ -217,8 +254,8 @@ SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)
 
 	file->f_flags |= O_LARGEFILE;
 
+	atomic_inc(&secretmem_users);
 	fd_install(fd, file);
-	refcount_inc(&secretmem_users);
 	return fd;
 
 err_put_fd:
@@ -246,7 +283,7 @@ static int secretmem_init(void)
 
 	secretmem_mnt = kern_mount(&secretmem_fs);
 	if (IS_ERR(secretmem_mnt))
-		ret = PTR_ERR(secretmem_mnt);
+		return PTR_ERR(secretmem_mnt);
 
 	/* prevent secretmem mappings from ever getting PROT_EXEC */
 	secretmem_mnt->mnt_flags |= MNT_NOEXEC;