io_uring: add flag for disabling provided buffer recycling

commit 8a3e8ee564 upstream.

If we need to continue doing this IO, then we don't want a potentially
selected buffer recycled. Add a flag for that.

Set this for recv/recvmsg if they do partial IO.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

io_uring/io_uring.c

@@ -740,6 +740,7 @@ enum {
 	REQ_F_CREDS_BIT,
 	REQ_F_REFCOUNT_BIT,
 	REQ_F_ARM_LTIMEOUT_BIT,
+	REQ_F_PARTIAL_IO_BIT,
 	/* keep async read/write and isreg together and in order */
 	REQ_F_NOWAIT_READ_BIT,
 	REQ_F_NOWAIT_WRITE_BIT,
@@ -795,6 +796,8 @@ enum {
 	REQ_F_REFCOUNT		= BIT(REQ_F_REFCOUNT_BIT),
 	/* there is a linked timeout that has to be armed */
 	REQ_F_ARM_LTIMEOUT	= BIT(REQ_F_ARM_LTIMEOUT_BIT),
+	/* request has already done partial IO */
+	REQ_F_PARTIAL_IO	= BIT(REQ_F_PARTIAL_IO_BIT),
 };
 
 struct async_poll {
@@ -5123,6 +5126,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
 			ret = -EINTR;
 		if (ret > 0 && io_net_retry(sock, flags)) {
 			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
 			return io_setup_async_msg(req, kmsg);
 		}
 		req_set_fail(req);
@@ -5196,6 +5200,7 @@ out_free:
 			sr->len -= ret;
 			sr->buf += ret;
 			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
 			return -EAGAIN;
 		}
 		req_set_fail(req);