This also restores the check which got removed in 52732bb9abc9ee5b
("fs/file.c: remove sanity_check and add likely/unlikely in alloc_fd()")
for performance reasons -- they no longer apply with a debug-only
variant.
Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
---
I have about 0 opinion whether this should be BUG or WARN, the code was
already inconsistent on this front. If you want the latter, I'll have 0
complaints if you just sed it and commit as yours.
This reminded me to sort out that litmus test for smp_rmb, hopefully
soon(tm) as it is now nagging me.
fs/file.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/file.c b/fs/file.c
index 6c159ede55f1..09460ec74ef8 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -582,6 +582,7 @@ static int alloc_fd(unsigned start, unsigned end, unsigned flags)
__set_open_fd(fd, fdt, flags & O_CLOEXEC);
error = fd;
+ VFS_BUG_ON(rcu_access_pointer(fdt->fd[fd]) != NULL);
out:
spin_unlock(&files->file_lock);
@@ -647,7 +648,7 @@ void fd_install(unsigned int fd, struct file *file)
rcu_read_unlock_sched();
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
- WARN_ON(fdt->fd[fd] != NULL);
+ VFS_BUG_ON(fdt->fd[fd] != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
spin_unlock(&files->file_lock);
return;
@@ -655,7 +656,7 @@ void fd_install(unsigned int fd, struct file *file)
/* coupled with smp_wmb() in expand_fdtable() */
smp_rmb();
fdt = rcu_dereference_sched(files->fdt);
- BUG_ON(fdt->fd[fd] != NULL);
+ VFS_BUG_ON(fdt->fd[fd] != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
rcu_read_unlock_sched();
}
--
2.43.0
