fixlet: Remove fs_excl from struct task.

fs_excl is a poor man's priority inheritance for filesystems to hint to
the block layer that an operation is important. It was never clearly
specified, not widely adopted, and will not prevent starvation in many
cases (like across cgroups).

fs_excl was introduced with the time sliced CFQ IO scheduler, to
indicate when a process held FS exclusive resources and thus needed
a boost.

It doesn't cover all file systems, and it was never fully complete.
Lets kill it.

Signed-off-by: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

2 files changed, 0 insertions, 2 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index f2b321bae440..b412df45ea6c 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -906,7 +906,6 @@ NORET_TYPE void do_exit(long code)
 
         profile_task_exit(tsk);
 
-        WARN_ON(atomic_read(&tsk->fs_excl));
         WARN_ON(blk_needs_flush_plug(tsk));
 
         if (unlikely(in_interrupt()))
diff --git a/kernel/fork.c b/kernel/fork.c
index 0276c30401a0..30a0e8607223 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -291,7 +291,6 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
 
         /* One for us, one for whoever does the "release_task()" (usually parent) */
         atomic_set(&tsk->usage,2);
-        atomic_set(&tsk->fs_excl, 0);
 #ifdef CONFIG_BLK_DEV_IO_TRACE
         tsk->btrace_seq = 0;
 #endif