block: Simplify bsg complete all
It took me a few tries to figure out what this code did; lets rewrite
it into a more regular form.
The thing that makes this one 'special' is the BSG_F_BLOCK flag, if
that is not set we're not supposed/allowed to block and should spin
wait for completion.
The (new) io_wait_event() will never see a false condition in case of
the spinning and we will therefore not block.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/bsg.c b/block/bsg.c
index 276e869..d214e92 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -136,42 +136,6 @@
return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
}
-static int bsg_io_schedule(struct bsg_device *bd)
-{
- DEFINE_WAIT(wait);
- int ret = 0;
-
- spin_lock_irq(&bd->lock);
-
- BUG_ON(bd->done_cmds > bd->queued_cmds);
-
- /*
- * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no
- * work to do", even though we return -ENOSPC after this same test
- * during bsg_write() -- there, it means our buffer can't have more
- * bsg_commands added to it, thus has no space left.
- */
- if (bd->done_cmds == bd->queued_cmds) {
- ret = -ENODATA;
- goto unlock;
- }
-
- if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
- ret = -EAGAIN;
- goto unlock;
- }
-
- prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE);
- spin_unlock_irq(&bd->lock);
- io_schedule();
- finish_wait(&bd->wq_done, &wait);
-
- return ret;
-unlock:
- spin_unlock_irq(&bd->lock);
- return ret;
-}
-
static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
struct sg_io_v4 *hdr, struct bsg_device *bd,
fmode_t has_write_perm)
@@ -482,6 +446,30 @@
return ret;
}
+static bool bsg_complete(struct bsg_device *bd)
+{
+ bool ret = false;
+ bool spin;
+
+ do {
+ spin_lock_irq(&bd->lock);
+
+ BUG_ON(bd->done_cmds > bd->queued_cmds);
+
+ /*
+ * All commands consumed.
+ */
+ if (bd->done_cmds == bd->queued_cmds)
+ ret = true;
+
+ spin = !test_bit(BSG_F_BLOCK, &bd->flags);
+
+ spin_unlock_irq(&bd->lock);
+ } while (!ret && spin);
+
+ return ret;
+}
+
static int bsg_complete_all_commands(struct bsg_device *bd)
{
struct bsg_command *bc;
@@ -492,17 +480,7 @@
/*
* wait for all commands to complete
*/
- ret = 0;
- do {
- ret = bsg_io_schedule(bd);
- /*
- * look for -ENODATA specifically -- we'll sometimes get
- * -ERESTARTSYS when we've taken a signal, but we can't
- * return until we're done freeing the queue, so ignore
- * it. The signal will get handled when we're done freeing
- * the bsg_device.
- */
- } while (ret != -ENODATA);
+ io_wait_event(bd->wq_done, bsg_complete(bd));
/*
* discard done commands