Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  [PATCH] pass struct path * to do_add_mount()
  [PATCH] switch mtd and dm-table to lookup_bdev()
  [patch 3/4] vfs: remove unused nameidata argument of may_create()
  [PATCH] devpts: switch to IDA
  [PATCH 2/2] proc: switch inode number allocation to IDA
  [PATCH 1/2] proc: fix inode number bogorithmetic
  [PATCH] fix bdev leak in block_dev.c do_open()
  [PATCH] fix races and leaks in vfs_quota_on() users
  [PATCH] clean dup2() up a bit
  [PATCH] merge locate_fd() and get_unused_fd()
  [PATCH] ipv4_static_sysctl_init() should be under CONFIG_SYSCTL
  Re: BUG at security/selinux/avc.c:883 (was: Re: linux-next: Tree

1 files changed, 61 insertions, 0 deletions

diff --git a/fs/file.c b/fs/file.c
index d8773b19fe4..f313314f996 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -6,6 +6,7 @@
  *  Manage the dynamic fd arrays in the process files_struct.
  */
 
+#include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/time.h>
@@ -432,3 +433,63 @@ struct files_struct init_files = {
 	},
 	.file_lock	= __SPIN_LOCK_UNLOCKED(init_task.file_lock),
 };
+
+/*
+ * allocate a file descriptor, mark it busy.
+ */
+int alloc_fd(unsigned start, unsigned flags)
+{
+	struct files_struct *files = current->files;
+	unsigned int fd;
+	int error;
+	struct fdtable *fdt;
+
+	spin_lock(&files->file_lock);
+repeat:
+	fdt = files_fdtable(files);
+	fd = start;
+	if (fd < files->next_fd)
+		fd = files->next_fd;
+
+	if (fd < fdt->max_fds)
+		fd = find_next_zero_bit(fdt->open_fds->fds_bits,
+					   fdt->max_fds, fd);
+
+	error = expand_files(files, fd);
+	if (error < 0)
+		goto out;
+
+	/*
+	 * If we needed to expand the fs array we
+	 * might have blocked - try again.
+	 */
+	if (error)
+		goto repeat;
+
+	if (start <= files->next_fd)
+		files->next_fd = fd + 1;
+
+	FD_SET(fd, fdt->open_fds);
+	if (flags & O_CLOEXEC)
+		FD_SET(fd, fdt->close_on_exec);
+	else
+		FD_CLR(fd, fdt->close_on_exec);
+	error = fd;
+#if 1
+	/* Sanity check */
+	if (rcu_dereference(fdt->fd[fd]) != NULL) {
+		printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
+		rcu_assign_pointer(fdt->fd[fd], NULL);
+	}
+#endif
+
+out:
+	spin_unlock(&files->file_lock);
+	return error;
+}
+
+int get_unused_fd(void)
+{
+	return alloc_fd(0, 0);
+}
+EXPORT_SYMBOL(get_unused_fd);