On Tue, 30 Nov 2010 17:06:04 +0200
Alexander Nezhinsky <alexandern@xxxxxxxxxxxx> wrote:
> When iscsi conn gets closed, some tasks may be still processed in scsi layer,
> and can't be released immediatelly, thus their release is delayed.
> But the conn release should be delayed too. To do this we can increment conn
Why do we need this?
iscsi_alloc_task calls conn_get() so as long as a task lives, its conn
never be freed?
> refcount per each task in scsi. Thus the last conn_put() in conn_close() will
> not lead to the conn destruction. Then we decrement the refcount when the
> tasks complete and ensure that the conn is freed when the last such task
> returns from scsi.
>
> Signed-off-by: Alexander Nezhinsky <alexandern@xxxxxxxxxxxx>
> ---
> usr/iscsi/conn.c | 11 ++++++++++-
> usr/iscsi/iscsid.c | 8 +++++++-
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/usr/iscsi/conn.c b/usr/iscsi/conn.c
> index a3af6a4..fa4096c 100644
> --- a/usr/iscsi/conn.c
> +++ b/usr/iscsi/conn.c
> @@ -173,8 +173,17 @@ void conn_close(struct iscsi_connection *conn)
> * This task is in SCSI. We need to wait for I/O
> * completion.
> */
> - if (task_in_scsi(task))
> + if (task_in_scsi(task)) {
> + /* We increment connection's refcount to allow
> + * the task to complete in scsi layer.
> + * Then we'll decrement it back and dispose of
> + * the connection when no such tasks remain.
> + */
> + dprintf("task %" PRIx64 " in_scsi, release delayed\n",
> + task->tag);
> + conn_get(conn);
> continue;
> + }
> iscsi_free_task(task);
> }
> done:
> diff --git a/usr/iscsi/iscsid.c b/usr/iscsi/iscsid.c
> index 3a79d93..050047e 100644
> --- a/usr/iscsi/iscsid.c
> +++ b/usr/iscsi/iscsid.c
> @@ -1184,9 +1184,15 @@ static int iscsi_scsi_cmd_done(uint64_t nid, int result, struct scsi_cmd *scmd)
> * We could delay the closing of the conn in some cases and send
> * the response with a little extra code or we can check if this
> * task got reassinged to another connection.
> + * When the connection was closing, its refcount got incremented
> + * for each in_scsi task whose release was delayed.
> + * Thus we need to decrement it back to enable proper
> + * connection and session release.
> */
> - if (task->conn->state == STATE_CLOSE) {
> + if (task->conn->closed) {
> + dprintf("task %" PRIx64 " from scsi, releasing\n", task->tag);
> iscsi_free_cmd_task(task);
> + conn_put(task->conn);
> return 0;
> }
>
> --
> 1.7.3.2
> --
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