[PATCH net-next v4 25/27] io_uring: add zc notification flush requests

Pavel Begunkov
2022-07-07T11:53:37Z

Overlay notification control onto IORING_OP_RSRC_UPDATE (former
IORING_OP_FILES_UPDATE). It allows to flush a range of zc notifications
from slots with indexes [sqe->off, sqe->off+sqe->len). If sqe->arg is
not zero, it also copies sqe->arg as a new tag for all flushed
notifications.

Note, it doesn't flush a notification of a slot if there was no requests
attached to it (since last flush or registration).

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
include/uapi/linux/io_uring.h | 1 +
io_uring/rsrc.c | 38 +++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 9e325179a4f8..cbf9cfbe5fe7 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -294,6 +294,7 @@ enum io_uring_op {
*/
enum {
IORING_RSRC_UPDATE_FILES,
+ IORING_RSRC_UPDATE_NOTIF,
};

/*
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 98ce8a93a816..088a2dc32e2c 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -15,6 +15,7 @@
#include "io_uring.h"
#include "openclose.h"
#include "rsrc.h"
+#include "notif.h"

struct io_rsrc_update {
struct file *file;
@@ -742,6 +743,41 @@ static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
return IOU_OK;
}

+static int io_notif_update(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_rsrc_update *up = io_kiocb_to_cmd(req);
+ struct io_ring_ctx *ctx = req->ctx;
+ unsigned len = up->nr_args;
+ unsigned idx_end, idx = up->offset;
+ int ret = 0;
+
+ io_ring_submit_lock(ctx, issue_flags);
+ if (unlikely(check_add_overflow(idx, len, &idx_end))) {
+ ret = -EOVERFLOW;
+ goto out;
+ }
+ if (unlikely(idx_end > ctx->nr_notif_slots)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ for (; idx < idx_end; idx++) {
+ struct io_notif_slot *slot = &ctx->notif_slots[idx];
+
+ if (!slot->notif)
+ continue;
+ if (up->arg)
+ slot->tag = up->arg;
+ io_notif_slot_flush_submit(slot, issue_flags);
+ }
+out:
+ io_ring_submit_unlock(ctx, issue_flags);
+ if (ret < 0)
+ req_set_fail(req);
+ io_req_set_res(req, ret, 0);
+ return IOU_OK;
+}
+
int io_rsrc_update(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req);
@@ -749,6 +785,8 @@ int io_rsrc_update(struct io_kiocb *req, unsigned int issue_flags)
switch (up->type) {
case IORING_RSRC_UPDATE_FILES:
return io_files_update(req, issue_flags);
+ case IORING_RSRC_UPDATE_NOTIF:
+ return io_notif_update(req, issue_flags);
}
return -EINVAL;
}
--
2.36.1