This new data structure allows a task to wait for N things to complete.
Usually the submitting task will handle cleanup, but if it is killed,
the last completer will take care of it.
Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
block/blk-core.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/bio.h | 11 ++++++++
2 files changed, 72 insertions(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index 10c08ac50697..2892246f2176 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1900,6 +1900,67 @@ void blk_io_schedule(void)
}
EXPORT_SYMBOL_GPL(blk_io_schedule);
+void blk_completion_init(struct blk_completion *cmpl, int n)
+{
+ spin_lock_init(&cmpl->cmpl_lock);
+ cmpl->cmpl_count = n;
+ cmpl->cmpl_task = current;
+ cmpl->cmpl_status = BLK_STS_OK;
+}
+
+int blk_completion_sub(struct blk_completion *cmpl, blk_status_t status, int n)
+{
+ int ret = 0;
+
+ spin_lock_bh(&cmpl->cmpl_lock);
+ if (cmpl->cmpl_status == BLK_STS_OK && status != BLK_STS_OK)
+ cmpl->cmpl_status = status;
+ cmpl->cmpl_count -= n;
+ BUG_ON(cmpl->cmpl_count < 0);
+ if (cmpl->cmpl_count == 0) {
+ if (cmpl->cmpl_task)
+ wake_up_process(cmpl->cmpl_task);
+ else
+ ret = -EINTR;
+ }
+ spin_unlock_bh(&cmpl->cmpl_lock);
+ if (ret < 0)
+ kfree(cmpl);
+ return ret;
+}
+
+int blk_completion_wait_killable(struct blk_completion *cmpl)
+{
+ int err = 0;
+
+ for (;;) {
+ set_current_state(TASK_KILLABLE);
+ spin_lock_bh(&cmpl->cmpl_lock);
+ if (cmpl->cmpl_count == 0)
+ break;
+ spin_unlock_bh(&cmpl->cmpl_lock);
+ blk_io_schedule();
+ if (fatal_signal_pending(current)) {
+ spin_lock_bh(&cmpl->cmpl_lock);
+ cmpl->cmpl_task = NULL;
+ if (cmpl->cmpl_count != 0) {
+ spin_unlock_bh(&cmpl->cmpl_lock);
+ cmpl = NULL;
+ }
+ err = -ERESTARTSYS;
+ break;
+ }
+ }
+ set_current_state(TASK_RUNNING);
+ if (cmpl) {
+ spin_unlock_bh(&cmpl->cmpl_lock);
+ err = blk_status_to_errno(cmpl->cmpl_status);
+ kfree(cmpl);
+ }
+
+ return err;
+}
+
int __init blk_dev_init(void)
{
BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS));
diff --git a/include/linux/bio.h b/include/linux/bio.h
index f254bc79bb3a..0bde05f5548c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -814,4 +814,15 @@ static inline void bio_set_polled(struct bio *bio, struct
kiocb *kiocb)
bio->bi_opf |= REQ_NOWAIT;
}
+struct blk_completion {
+ struct task_struct *cmpl_task;
+ spinlock_t cmpl_lock;
+ int cmpl_count;
+ blk_status_t cmpl_status;
+};
+
+void blk_completion_init(struct blk_completion *, int n);
+int blk_completion_sub(struct blk_completion *, blk_status_t status, int n);
+int blk_completion_wait_killable(struct blk_completion *);
+
#endif /* __LINUX_BIO_H */
--
2.28.0
