1 files changed, 51 insertions, 72 deletions

diff --git a/fs/file.c b/fs/file.c
index 4a78f981557a..eb56a13dab3e 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -34,7 +34,7 @@ static void *alloc_fdmem(size_t size)
 	 * vmalloc() if the allocation size will be considered "large" by the VM.
 	 */
 	if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
-		void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
+		void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY);
 		if (data != NULL)
 			return data;
 	}
@@ -348,21 +348,16 @@ out:
 	return NULL;
 }
 
-static void close_files(struct files_struct * files)
+static struct fdtable *close_files(struct files_struct * files)
 {
-	int i, j;
-	struct fdtable *fdt;
-
-	j = 0;
-
 	/*
 	 * It is safe to dereference the fd table without RCU or
 	 * ->file_lock because this is the last reference to the
-	 * files structure.  But use RCU to shut RCU-lockdep up.
+	 * files structure.
 	 */
-	rcu_read_lock();
-	fdt = files_fdtable(files);
-	rcu_read_unlock();
+	struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+	int i, j = 0;
+
 	for (;;) {
 		unsigned long set;
 		i = j * BITS_PER_LONG;
@@ -381,6 +376,8 @@ static void close_files(struct files_struct * files)
 			set >>= 1;
 		}
 	}
+
+	return fdt;
 }
 
 struct files_struct *get_files_struct(struct task_struct *task)
@@ -398,14 +395,9 @@ struct files_struct *get_files_struct(struct task_struct *task)
 
 void put_files_struct(struct files_struct *files)
 {
-	struct fdtable *fdt;
-
 	if (atomic_dec_and_test(&files->count)) {
-		close_files(files);
-		/* not really needed, since nobody can see us */
-		rcu_read_lock();
-		fdt = files_fdtable(files);
-		rcu_read_unlock();
+		struct fdtable *fdt = close_files(files);
+
 		/* free the arrays if they are not embedded */
 		if (fdt != &files->fdtab)
 			__free_fdtable(fdt);
@@ -645,16 +637,16 @@ void do_close_on_exec(struct files_struct *files)
 	spin_unlock(&files->file_lock);
 }
 
-struct file *fget(unsigned int fd)
+static struct file *__fget(unsigned int fd, fmode_t mask)
 {
-	struct file *file;
 	struct files_struct *files = current->files;
+	struct file *file;
 
 	rcu_read_lock();
 	file = fcheck_files(files, fd);
 	if (file) {
 		/* File object ref couldn't be taken */
-		if (file->f_mode & FMODE_PATH ||
+		if ((file->f_mode & mask) ||
 		    !atomic_long_inc_not_zero(&file->f_count))
 			file = NULL;
 	}
@@ -663,25 +655,16 @@ struct file *fget(unsigned int fd)
 	return file;
 }
 
+struct file *fget(unsigned int fd)
+{
+	return __fget(fd, FMODE_PATH);
+}
 EXPORT_SYMBOL(fget);
 
 struct file *fget_raw(unsigned int fd)
 {
-	struct file *file;
-	struct files_struct *files = current->files;
-
-	rcu_read_lock();
-	file = fcheck_files(files, fd);
-	if (file) {
-		/* File object ref couldn't be taken */
-		if (!atomic_long_inc_not_zero(&file->f_count))
-			file = NULL;
-	}
-	rcu_read_unlock();
-
-	return file;
+	return __fget(fd, 0);
 }
-
 EXPORT_SYMBOL(fget_raw);
 
 /*
@@ -700,58 +683,54 @@ EXPORT_SYMBOL(fget_raw);
  * The fput_needed flag returned by fget_light should be passed to the
  * corresponding fput_light.
  */
-struct file *fget_light(unsigned int fd, int *fput_needed)
+static unsigned long __fget_light(unsigned int fd, fmode_t mask)
 {
-	struct file *file;
 	struct files_struct *files = current->files;
+	struct file *file;
 
-	*fput_needed = 0;
 	if (atomic_read(&files->count) == 1) {
-		file = fcheck_files(files, fd);
-		if (file && (file->f_mode & FMODE_PATH))
-			file = NULL;
+		file = __fcheck_files(files, fd);
+		if (!file || unlikely(file->f_mode & mask))
+			return 0;
+		return (unsigned long)file;
 	} else {
-		rcu_read_lock();
-		file = fcheck_files(files, fd);
-		if (file) {
-			if (!(file->f_mode & FMODE_PATH) &&
-			    atomic_long_inc_not_zero(&file->f_count))
-				*fput_needed = 1;
-			else
-				/* Didn't get the reference, someone's freed */
-				file = NULL;
-		}
-		rcu_read_unlock();
+		file = __fget(fd, mask);
+		if (!file)
+			return 0;
+		return FDPUT_FPUT | (unsigned long)file;
 	}
+}
+unsigned long __fdget(unsigned int fd)
+{
+	return __fget_light(fd, FMODE_PATH);
+}
+EXPORT_SYMBOL(__fdget);
 
-	return file;
+unsigned long __fdget_raw(unsigned int fd)
+{
+	return __fget_light(fd, 0);
 }
-EXPORT_SYMBOL(fget_light);
 
-struct file *fget_raw_light(unsigned int fd, int *fput_needed)
+unsigned long __fdget_pos(unsigned int fd)
 {
-	struct file *file;
-	struct files_struct *files = current->files;
+	unsigned long v = __fdget(fd);
+	struct file *file = (struct file *)(v & ~3);
 
-	*fput_needed = 0;
-	if (atomic_read(&files->count) == 1) {
-		file = fcheck_files(files, fd);
-	} else {
-		rcu_read_lock();
-		file = fcheck_files(files, fd);
-		if (file) {
-			if (atomic_long_inc_not_zero(&file->f_count))
-				*fput_needed = 1;
-			else
-				/* Didn't get the reference, someone's freed */
-				file = NULL;
+	if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
+		if (file_count(file) > 1) {
+			v |= FDPUT_POS_UNLOCK;
+			mutex_lock(&file->f_pos_lock);
 		}
-		rcu_read_unlock();
 	}
-
-	return file;
+	return v;
 }
 
+/*
+ * We only lock f_pos if we have threads or if the file might be
+ * shared with another process. In both cases we'll have an elevated
+ * file count (done either by fdget() or by fork()).
+ */
+
 void set_close_on_exec(unsigned int fd, int flag)
 {
 	struct files_struct *files = current->files;