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authorKent Overstreet <kent.overstreet@gmail.com>2018-01-08 21:21:25 +0100
committerJens Axboe <axboe@kernel.dk>2018-01-08 21:29:00 +0100
commite4bf791937d82afca79e1df4063f72dbc6960ac7 (patch)
tree5c131edb13307bce302ba252a2624cca71176ba7 /drivers/md/bcache/closure.c
parentbcache: allow quick writeback when backing idle (diff)
downloadlinux-e4bf791937d82afca79e1df4063f72dbc6960ac7.tar.xz
linux-e4bf791937d82afca79e1df4063f72dbc6960ac7.zip
bcache: Fix, improve efficiency of closure_sync()
Eliminates cases where sync can race and fail to complete / get stuck. Removes many status flags and simplifies entering-and-exiting closure sleeping behaviors. [mlyle: fixed conflicts due to changed return behavior in mainline. extended commit comment, and squashed down two commits that were mostly contradictory to get to this state. Changed __set_current_state to set_current_state per Jens review comment] Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Michael Lyle <mlyle@lyle.org> Reviewed-by: Michael Lyle <mlyle@lyle.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache/closure.c')
-rw-r--r--drivers/md/bcache/closure.c46
1 files changed, 23 insertions, 23 deletions
diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c
index 1841d0359bac..ca7ace6962a4 100644
--- a/drivers/md/bcache/closure.c
+++ b/drivers/md/bcache/closure.c
@@ -18,10 +18,6 @@ static inline void closure_put_after_sub(struct closure *cl, int flags)
BUG_ON(flags & CLOSURE_GUARD_MASK);
BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
- /* Must deliver precisely one wakeup */
- if (r == 1 && (flags & CLOSURE_SLEEPING))
- wake_up_process(cl->task);
-
if (!r) {
if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
atomic_set(&cl->remaining,
@@ -100,28 +96,34 @@ bool closure_wait(struct closure_waitlist *waitlist, struct closure *cl)
}
EXPORT_SYMBOL(closure_wait);
-/**
- * closure_sync - sleep until a closure has nothing left to wait on
- *
- * Sleeps until the refcount hits 1 - the thread that's running the closure owns
- * the last refcount.
- */
-void closure_sync(struct closure *cl)
+struct closure_syncer {
+ struct task_struct *task;
+ int done;
+};
+
+static void closure_sync_fn(struct closure *cl)
{
- while (1) {
- __closure_start_sleep(cl);
- closure_set_ret_ip(cl);
+ cl->s->done = 1;
+ wake_up_process(cl->s->task);
+}
- if ((atomic_read(&cl->remaining) &
- CLOSURE_REMAINING_MASK) == 1)
- break;
+void __closure_sync(struct closure *cl)
+{
+ struct closure_syncer s = { .task = current };
+ cl->s = &s;
+ continue_at(cl, closure_sync_fn, NULL);
+
+ while (1) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (s.done)
+ break;
schedule();
}
- __closure_end_sleep(cl);
+ __set_current_state(TASK_RUNNING);
}
-EXPORT_SYMBOL(closure_sync);
+EXPORT_SYMBOL(__closure_sync);
#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
@@ -168,12 +170,10 @@ static int debug_seq_show(struct seq_file *f, void *data)
cl, (void *) cl->ip, cl->fn, cl->parent,
r & CLOSURE_REMAINING_MASK);
- seq_printf(f, "%s%s%s%s\n",
+ seq_printf(f, "%s%s\n",
test_bit(WORK_STRUCT_PENDING_BIT,
work_data_bits(&cl->work)) ? "Q" : "",
- r & CLOSURE_RUNNING ? "R" : "",
- r & CLOSURE_STACK ? "S" : "",
- r & CLOSURE_SLEEPING ? "Sl" : "");
+ r & CLOSURE_RUNNING ? "R" : "");
if (r & CLOSURE_WAITING)
seq_printf(f, " W %pF\n",