This is a note to let you know that I've just added the patch titled
io_uring: enable task/files specific overflow flushing
to the 5.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
io_uring-enable-task-files-specific-overflow-flushing.patch
and it can be found in the queue-5.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Oct 29 01:16:54 PM CET 2020
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Mon, 28 Sep 2020 13:10:13 -0600
Subject: io_uring: enable task/files specific overflow flushing
From: Jens Axboe <axboe@xxxxxxxxx>
commit e6c8aa9ac33bd7c968af7816240fc081401fddcd upstream.
This allows us to selectively flush out pending overflows, depending on
the task and/or files_struct being passed in.
No intended functional changes in this patch.
Reviewed-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 41 ++++++++++++++++++++++++++---------------
1 file changed, 26 insertions(+), 15 deletions(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1240,12 +1240,24 @@ static void io_cqring_ev_posted(struct i
eventfd_signal(ctx->cq_ev_fd, 1);
}
+static inline bool io_match_files(struct io_kiocb *req,
+ struct files_struct *files)
+{
+ if (!files)
+ return true;
+ if (req->flags & REQ_F_WORK_INITIALIZED)
+ return req->work.files == files;
+ return false;
+}
+
/* Returns true if there are no backlogged entries after the flush */
-static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
+static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
+ struct task_struct *tsk,
+ struct files_struct *files)
{
struct io_rings *rings = ctx->rings;
+ struct io_kiocb *req, *tmp;
struct io_uring_cqe *cqe;
- struct io_kiocb *req;
unsigned long flags;
LIST_HEAD(list);
@@ -1264,7 +1276,12 @@ static bool io_cqring_overflow_flush(str
ctx->cq_overflow_flushed = 1;
cqe = NULL;
- while (!list_empty(&ctx->cq_overflow_list)) {
+ list_for_each_entry_safe(req, tmp, &ctx->cq_overflow_list, list) {
+ if (tsk && req->task != tsk)
+ continue;
+ if (!io_match_files(req, files))
+ continue;
+
cqe = io_get_cqring(ctx);
if (!cqe && !force)
break;
@@ -1734,7 +1751,7 @@ static unsigned io_cqring_events(struct
if (noflush && !list_empty(&ctx->cq_overflow_list))
return -1U;
- io_cqring_overflow_flush(ctx, false);
+ io_cqring_overflow_flush(ctx, false, NULL, NULL);
}
/* See comment at the top of this file */
@@ -6095,7 +6112,7 @@ static int io_submit_sqes(struct io_ring
/* if we have a backlog and couldn't flush it all, return BUSY */
if (test_bit(0, &ctx->sq_check_overflow)) {
if (!list_empty(&ctx->cq_overflow_list) &&
- !io_cqring_overflow_flush(ctx, false))
+ !io_cqring_overflow_flush(ctx, false, NULL, NULL))
return -EBUSY;
}
@@ -7556,7 +7573,7 @@ static void io_ring_exit_work(struct wor
ctx = container_of(work, struct io_ring_ctx, exit_work);
if (ctx->rings)
- io_cqring_overflow_flush(ctx, true);
+ io_cqring_overflow_flush(ctx, true, NULL, NULL);
/*
* If we're doing polled IO and end up having requests being
@@ -7567,7 +7584,7 @@ static void io_ring_exit_work(struct wor
while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)) {
io_iopoll_reap_events(ctx);
if (ctx->rings)
- io_cqring_overflow_flush(ctx, true);
+ io_cqring_overflow_flush(ctx, true, NULL, NULL);
}
io_ring_ctx_free(ctx);
}
@@ -7587,7 +7604,7 @@ static void io_ring_ctx_wait_and_kill(st
io_iopoll_reap_events(ctx);
/* if we failed setting up the ctx, we might not have any rings */
if (ctx->rings)
- io_cqring_overflow_flush(ctx, true);
+ io_cqring_overflow_flush(ctx, true, NULL, NULL);
idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
/*
@@ -7637,12 +7654,6 @@ static bool io_match_link(struct io_kioc
return false;
}
-static inline bool io_match_files(struct io_kiocb *req,
- struct files_struct *files)
-{
- return (req->flags & REQ_F_WORK_INITIALIZED) && req->work.files == files;
-}
-
static bool io_match_link_files(struct io_kiocb *req,
struct files_struct *files)
{
@@ -7959,7 +7970,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (!list_empty_careful(&ctx->cq_overflow_list))
- io_cqring_overflow_flush(ctx, false);
+ io_cqring_overflow_flush(ctx, false, NULL, NULL);
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sqo_wait);
submitted = to_submit;
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-5.8/io_uring-convert-advanced-xarray-uses-to-the-normal-api.patch
queue-5.8/io_uring-don-t-run-task-work-on-an-exiting-task.patch
queue-5.8/io_uring-reference-nsproxy-for-file-table-commands.patch
queue-5.8/io_uring-stash-ctx-task-reference-for-sqpoll.patch
queue-5.8/io_uring-return-cancelation-status-from-poll-timeout-files-handlers.patch
queue-5.8/io_uring-fix-xarray-usage-in-io_uring_add_task_file.patch
queue-5.8/io_uring-fix-use-of-xarray-in-__io_uring_files_cancel.patch
queue-5.8/io-wq-fix-use-after-free-in-io_wq_worker_running.patch
queue-5.8/io_uring-don-t-rely-on-weak-files-references.patch
queue-5.8/io_uring-allow-timeout-poll-files-killing-to-take-task-into-account.patch
queue-5.8/io_uring-move-dropping-of-files-into-separate-helper.patch
queue-5.8/io_uring-unconditionally-grab-req-task.patch
queue-5.8/io_uring-enable-task-files-specific-overflow-flushing.patch
queue-5.8/io_wq-make-io_wqe-lock-a-raw_spinlock_t.patch
queue-5.8/io_uring-no-need-to-call-xa_destroy-on-empty-xarray.patch
