From 03ba0fe4d09f2eb0a91888caaa057ed67462ae2d Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 2 Apr 2021 10:38:09 +0200 Subject: file: simplify logic in __close_range() It never looked too pleasant and it doesn't really buy us anything anymore now that CLOSE_RANGE_CLOEXEC exists and we need to retake the current maximum under the lock for it anyway. This also makes the logic easier to follow. Cc: Christoph Hellwig Cc: Giuseppe Scrivano Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/file.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) (limited to 'fs/file.c') diff --git a/fs/file.c b/fs/file.c index 740040346a98..ed46cd3ae225 100644 --- a/fs/file.c +++ b/fs/file.c @@ -701,7 +701,6 @@ static inline void __range_close(struct files_struct *cur_fds, unsigned int fd, */ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) { - unsigned int cur_max; struct task_struct *me = current; struct files_struct *cur_fds = me->files, *fds = NULL; @@ -711,26 +710,26 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) if (fd > max_fd) return -EINVAL; - rcu_read_lock(); - cur_max = files_fdtable(cur_fds)->max_fds; - rcu_read_unlock(); - - /* cap to last valid index into fdtable */ - cur_max--; - if (flags & CLOSE_RANGE_UNSHARE) { int ret; unsigned int max_unshare_fds = NR_OPEN_MAX; /* - * If the requested range is greater than the current maximum, - * we're closing everything so only copy all file descriptors - * beneath the lowest file descriptor. - * If the caller requested all fds to be made cloexec copy all - * of the file descriptors since they still want to use them. + * If the caller requested all fds to be made cloexec we always + * copy all of the file descriptors since they still want to + * use them. */ - if (!(flags & CLOSE_RANGE_CLOEXEC) && (max_fd >= cur_max)) - max_unshare_fds = fd; + if (!(flags & CLOSE_RANGE_CLOEXEC)) { + /* + * If the requested range is greater than the current + * maximum, we're closing everything so only copy all + * file descriptors beneath the lowest file descriptor. + */ + rcu_read_lock(); + if (max_fd >= last_fd(files_fdtable(cur_fds))) + max_unshare_fds = fd; + rcu_read_unlock(); + } ret = unshare_fd(CLONE_FILES, max_unshare_fds, &fds); if (ret) @@ -744,8 +743,6 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) swap(cur_fds, fds); } - max_fd = min(max_fd, cur_max); - if (flags & CLOSE_RANGE_CLOEXEC) __range_cloexec(cur_fds, fd, max_fd); else -- cgit v1.2.3