Re: [PATCH v3 3/3] libceph: just wait for more data to be available on the socket

From: Ilya Dryomov <idryomov@gmail.com>
To: Xiubo Li <xiubli@redhat.com>
Cc: ceph-devel@vger.kernel.org, jlayton@kernel.org,
	vshankar@redhat.com,  mchangir@redhat.com
Subject: Re: [PATCH v3 3/3] libceph: just wait for more data to be available on the socket
Date: Mon, 22 Jan 2024 22:26:16 +0100	[thread overview]
Message-ID: <CAOi1vP9TZ6q5GQvN6Yi+E8xFSVGErFQNS30VB-QN4fi4tL77XQ@mail.gmail.com> (raw)
In-Reply-To: <CAOi1vP_Ht9xM=k5FvXEnjAOP0kvp_rebpz+ehvmGoaOZXgMhwQ@mail.gmail.com>

On Mon, Jan 22, 2024 at 8:13 PM Ilya Dryomov <idryomov@gmail.com> wrote:
> I wouldn't object to cursor->sr_total_resid being added, I just don't
> like it ;)

Actually, how about just reusing cursor->sr_resid, which happens to be
an int?  Set it to -1 when con->ops->sparse_read() returns 0 and check
for that at the top:

    struct ceph_msg_data_cursor *cursor = &con->in_msg->cursor;
    bool do_datacrc = !ceph_test_opt(from_msgr(con->msgr), NOCRC);
    u32 crc = 0;
    int ret = 1;

    if (cursor->sr_resid < 0)
            return 1;

    if (do_datacrc)
            crc = con->in_data_crc;

    [ ... no changes ... ]

    if (do_datacrc)
            con->in_data_crc = crc;

    if (ret < 0)
            return ret;

    cursor->sr_resid = -1;
    return 1;  /* must return > 0 to indicate success */

Thanks,

                Ilya