Re: [PATCH 1/6] block: Add blk_completion
From: Christoph Hellwig <hch@infradead.org>
Date: 2020-10-27 18:30:43
Also in:
linux-fscrypt, linux-fsdevel, lkml
On Thu, Oct 22, 2020 at 10:22:23PM +0100, Matthew Wilcox (Oracle) wrote:
quoted hunk ↗ jump to hunk
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) <willy@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)
This needs documentation. e.g. to explain what 'n' is.
+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;
+}What are the life time rules for cmpl? Who frees it in the case of a fatal signal?