Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull execve updates from Eric Biederman:
 "This set of changes ultimately fixes the interaction of posix file
  lock and exec. Fundamentally most of the change is just moving where
  unshare_files is called during exec, and tweaking the users of
  files_struct so that the count of files_struct is not unnecessarily
  played with.

  Along the way fcheck and related helpers were renamed to more
  accurately reflect what they do.

  There were also many other small changes that fell out, as this is the
  first time in a long time much of this code has been touched.

  Benchmarks haven't turned up any practical issues but Al Viro has
  observed a possibility for a lot of pounding on task_lock. So I have
  some changes in progress to convert put_files_struct to always rcu
  free files_struct. That wasn't ready for the merge window so that will
  have to wait until next time"

* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
  exec: Move io_uring_task_cancel after the point of no return
  coredump: Document coredump code exclusively used by cell spufs
  file: Remove get_files_struct
  file: Rename __close_fd_get_file close_fd_get_file
  file: Replace ksys_close with close_fd
  file: Rename __close_fd to close_fd and remove the files parameter
  file: Merge __alloc_fd into alloc_fd
  file: In f_dupfd read RLIMIT_NOFILE once.
  file: Merge __fd_install into fd_install
  proc/fd: In fdinfo seq_show don't use get_files_struct
  bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
  proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
  file: Implement task_lookup_next_fd_rcu
  kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
  proc/fd: In tid_fd_mode use task_lookup_fd_rcu
  file: Implement task_lookup_fd_rcu
  file: Rename fcheck lookup_fd_rcu
  file: Replace fcheck_files with files_lookup_fd_rcu
  file: Factor files_lookup_fd_locked out of fcheck_files
  file: Rename __fcheck_files to files_lookup_fd_raw
  ...

2 files changed, 21 insertions, 31 deletions

diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index a32bf47c593e..d0e78174874a 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -80,7 +80,7 @@ struct dentry;
 /*
  * The caller must ensure that fd table isn't shared or hold rcu or file lock
  */
-static inline struct file *__fcheck_files(struct files_struct *files, unsigned int fd)
+static inline struct file *files_lookup_fd_raw(struct files_struct *files, unsigned int fd)
 {
 	struct fdtable *fdt = rcu_dereference_raw(files->fdt);
 
@@ -91,39 +91,41 @@ static inline struct file *__fcheck_files(struct files_struct *files, unsigned i
 	return NULL;
 }
 
-static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd)
+static inline struct file *files_lookup_fd_locked(struct files_struct *files, unsigned int fd)
 {
-	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
-			   !lockdep_is_held(&files->file_lock),
+	RCU_LOCKDEP_WARN(!lockdep_is_held(&files->file_lock),
 			   "suspicious rcu_dereference_check() usage");
-	return __fcheck_files(files, fd);
+	return files_lookup_fd_raw(files, fd);
 }
 
-/*
- * Check whether the specified fd has an open file.
- */
-#define fcheck(fd)	fcheck_files(current->files, fd)
+static inline struct file *files_lookup_fd_rcu(struct files_struct *files, unsigned int fd)
+{
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
+			   "suspicious rcu_dereference_check() usage");
+	return files_lookup_fd_raw(files, fd);
+}
+
+static inline struct file *lookup_fd_rcu(unsigned int fd)
+{
+	return files_lookup_fd_rcu(current->files, fd);
+}
+
+struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd);
+struct file *task_lookup_next_fd_rcu(struct task_struct *task, unsigned int *fd);
 
 struct task_struct;
 
-struct files_struct *get_files_struct(struct task_struct *);
 void put_files_struct(struct files_struct *fs);
-void reset_files_struct(struct files_struct *);
-int unshare_files(struct files_struct **);
+int unshare_files(void);
 struct files_struct *dup_fd(struct files_struct *, unsigned, int *) __latent_entropy;
 void do_close_on_exec(struct files_struct *);
 int iterate_fd(struct files_struct *, unsigned,
 		int (*)(const void *, struct file *, unsigned),
 		const void *);
 
-extern int __alloc_fd(struct files_struct *files,
-		      unsigned start, unsigned end, unsigned flags);
-extern void __fd_install(struct files_struct *files,
-		      unsigned int fd, struct file *file);
-extern int __close_fd(struct files_struct *files,
-		      unsigned int fd);
+extern int close_fd(unsigned int fd);
 extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags);
-extern int __close_fd_get_file(unsigned int fd, struct file **res);
+extern int close_fd_get_file(unsigned int fd, struct file **res);
 extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
 		      struct files_struct **new_fdp);
 
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 37bea07c12f2..0f72f380db72 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1295,18 +1295,6 @@ static inline long ksys_ftruncate(unsigned int fd, loff_t length)
 	return do_sys_ftruncate(fd, length, 1);
 }
 
-extern int __close_fd(struct files_struct *files, unsigned int fd);
-
-/*
- * In contrast to sys_close(), this stub does not check whether the syscall
- * should or should not be restarted, but returns the raw error codes from
- * __close_fd().
- */
-static inline int ksys_close(unsigned int fd)
-{
-	return __close_fd(current->files, fd);
-}
-
 extern long do_sys_truncate(const char __user *pathname, loff_t length);
 
 static inline long ksys_truncate(const char __user *pathname, loff_t length)