[PATCH 17/23] proc: Teach /proc//fd to use file_hotplug_lock

Eric W. Biederman
2009-06-03T18:44:27Z

From: Eric W. Biederman <ebiederm@maxwell.arastra.com>

I have taken the opportunity to modify proc_fd_info to have
a single exit point.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/proc/base.c | 29 ++++++++++++++++-------------
1 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index fb45615..ee4cdc2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1626,6 +1626,7 @@ static int proc_fd_info(struct inode *inode, struct path *path, char *info)
struct files_struct *files = NULL;
struct file *file;
int fd = proc_fd(inode);
+ int retval = -ENOENT;

if (task) {
files = get_files_struct(task);
@@ -1639,24 +1640,26 @@ static int proc_fd_info(struct inode *inode, struct path *path, char *info)
spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (file) {
- if (path) {
- *path = file->f_path;
- path_get(&file->f_path);
+ retval = -EIO;
+ if (file_hotplug_read_trylock(file)) {
+ retval = 0;
+ if (path) {
+ *path = file->f_path;
+ path_get(&file->f_path);
+ }
+ if (info)
+ snprintf(info, PROC_FDINFO_MAX,
+ "pos:\t%lli\n"
+ "flags:\t0%o\n",
+ (long long) file->f_pos,
+ file->f_flags);
+ file_hotplug_read_unlock(file);
}
- if (info)
- snprintf(info, PROC_FDINFO_MAX,
- "pos:\t%lli\n"
- "flags:\t0%o\n",
- (long long) file->f_pos,
- file->f_flags);
- spin_unlock(&files->file_lock);
- put_files_struct(files);
- return 0;
}
spin_unlock(&files->file_lock);
put_files_struct(files);
}
- return -ENOENT;
+ return retval;
}

static int proc_fd_link(struct inode *inode, struct path *path)
--
1.6.3.1.54.g99dd.dirty