KVM: s390: use WARN_ON_ONCE only for checking

[sfrench/cifs-2.6.git] / kernel / kcmp.c

diff --git a/kernel/kcmp.c b/kernel/kcmp.c
index 3a47fa998fe07277c592f62de36f59dad0d09f8b..ea34ed8bb9529c7b7a2a38b0a4e050995b4ba97e 100644 (file)
--- a/kernel/kcmp.c
+++ b/kernel/kcmp.c
@@ -11,6 +11,10 @@
 #include <linux/bug.h>
 #include <linux/err.h>
 #include <linux/kcmp.h>
+#include <linux/capability.h>
+#include <linux/list.h>
+#include <linux/eventpoll.h>
+#include <linux/file.h>
 
 #include <asm/unistd.h>
 
@@ -94,6 +98,56 @@ static int kcmp_lock(struct mutex *m1, struct mutex *m2)
        return err;
 }
 
+#ifdef CONFIG_EPOLL
+static int kcmp_epoll_target(struct task_struct *task1,
+                            struct task_struct *task2,
+                            unsigned long idx1,
+                            struct kcmp_epoll_slot __user *uslot)
+{
+       struct file *filp, *filp_epoll, *filp_tgt;
+       struct kcmp_epoll_slot slot;
+       struct files_struct *files;
+
+       if (copy_from_user(&slot, uslot, sizeof(slot)))
+               return -EFAULT;
+
+       filp = get_file_raw_ptr(task1, idx1);
+       if (!filp)
+               return -EBADF;
+
+       files = get_files_struct(task2);
+       if (!files)
+               return -EBADF;
+
+       spin_lock(&files->file_lock);
+       filp_epoll = fcheck_files(files, slot.efd);
+       if (filp_epoll)
+               get_file(filp_epoll);
+       else
+               filp_tgt = ERR_PTR(-EBADF);
+       spin_unlock(&files->file_lock);
+       put_files_struct(files);
+
+       if (filp_epoll) {
+               filp_tgt = get_epoll_tfile_raw_ptr(filp_epoll, slot.tfd, slot.toff);
+               fput(filp_epoll);
+       } else
+
+       if (IS_ERR(filp_tgt))
+               return PTR_ERR(filp_tgt);
+
+       return kcmp_ptr(filp, filp_tgt, KCMP_FILE);
+}
+#else
+static int kcmp_epoll_target(struct task_struct *task1,
+                            struct task_struct *task2,
+                            unsigned long idx1,
+                            struct kcmp_epoll_slot __user *uslot)
+{
+       return -EOPNOTSUPP;
+}
+#endif
+
 SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
                unsigned long, idx1, unsigned long, idx2)
 {
@@ -165,6 +219,9 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
                ret = -EOPNOTSUPP;
 #endif
                break;
+       case KCMP_EPOLL_TFD:
+               ret = kcmp_epoll_target(task1, task2, idx1, (void *)idx2);
+               break;
        default:
                ret = -EINVAL;
                break;