Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c

kernel/cgroup.c is the only place in the tree that relies on eventfd.h
pulling file.h; move that include there.  Switch from eventfd_fget()/fput()
to fdget()/fdput(), while we are at it - eventfd_ctx_fileget() will fail
on non-eventfd descriptors just fine, no need to do that check twice...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 16 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index e0aeb32415ff..2418b6e71a85 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -60,6 +60,7 @@
 #include <linux/poll.h>
 #include <linux/flex_array.h> /* used in cgroup_attach_task */
 #include <linux/kthread.h>
+#include <linux/file.h>
 
 #include <linux/atomic.h>
 
@@ -4034,8 +4035,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
         struct cgroup_event *event;
         struct cgroup_subsys_state *cfile_css;
         unsigned int efd, cfd;
-        struct file *efile;
-        struct file *cfile;
+        struct fd efile;
+        struct fd cfile;
         char *endp;
         int ret;
 
@@ -4058,31 +4059,31 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
         init_waitqueue_func_entry(&event->wait, cgroup_event_wake);
         INIT_WORK(&event->remove, cgroup_event_remove);
 
-        efile = eventfd_fget(efd);
-        if (IS_ERR(efile)) {
-                ret = PTR_ERR(efile);
+        efile = fdget(efd);
+        if (!efile.file) {
+                ret = -EBADF;
                 goto out_kfree;
         }
 
-        event->eventfd = eventfd_ctx_fileget(efile);
+        event->eventfd = eventfd_ctx_fileget(efile.file);
         if (IS_ERR(event->eventfd)) {
                 ret = PTR_ERR(event->eventfd);
                 goto out_put_efile;
         }
 
-        cfile = fget(cfd);
-        if (!cfile) {
+        cfile = fdget(cfd);
+        if (!cfile.file) {
                 ret = -EBADF;
                 goto out_put_eventfd;
         }
 
         /* the process need read permission on control file */
         /* AV: shouldn't we check that it's been opened for read instead? */
-        ret = inode_permission(file_inode(cfile), MAY_READ);
+        ret = inode_permission(file_inode(cfile.file), MAY_READ);
         if (ret < 0)
                 goto out_put_cfile;
 
-        event->cft = __file_cft(cfile);
+        event->cft = __file_cft(cfile.file);
         if (IS_ERR(event->cft)) {
                 ret = PTR_ERR(event->cft);
                 goto out_put_cfile;
@@ -4103,7 +4104,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
 
         ret = -EINVAL;
         event->css = cgroup_css(cgrp, event->cft->ss);
-        cfile_css = css_from_dir(cfile->f_dentry->d_parent, event->cft->ss);
+        cfile_css = css_from_dir(cfile.file->f_dentry->d_parent, event->cft->ss);
         if (event->css && event->css == cfile_css && css_tryget(event->css))
                 ret = 0;
 
@@ -4121,25 +4122,25 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
         if (ret)
                 goto out_put_css;
 
-        efile->f_op->poll(efile, &event->pt);
+        efile.file->f_op->poll(efile.file, &event->pt);
 
         spin_lock(&cgrp->event_list_lock);
         list_add(&event->list, &cgrp->event_list);
         spin_unlock(&cgrp->event_list_lock);
 
-        fput(cfile);
-        fput(efile);
+        fdput(cfile);
+        fdput(efile);
 
         return 0;
 
 out_put_css:
         css_put(event->css);
 out_put_cfile:
-        fput(cfile);
+        fdput(cfile);
 out_put_eventfd:
         eventfd_ctx_put(event->eventfd);
 out_put_efile:
-        fput(efile);
+        fdput(efile);
 out_kfree:
         kfree(event);