From: Nicholas Bellinger Date: Thu, 3 Nov 2011 04:52:08 +0000 (-0700) Subject: target: Add generic active I/O shutdown logic X-Git-Tag: v3.2-rc1~24^2~6 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a17f091d1a7c570804cfc2c77701634da88f8ecf;p=pandora-kernel.git target: Add generic active I/O shutdown logic This patch adds the initial pieces of generic active I/O shutdown logic. This is intended to be a 'opt-in' feature for fabric modules that includes the following functions to provide a mechinism for fabric modules to track se_cmd via se_session->sess_cmd_list: *) target_get_sess_cmd() - Add se_cmd to sess->sess_cmd_list, called from fabric module incoming I/O path. *) target_put_sess_cmd() - Check for completion or drop se_cmd from ->sess_cmd_list *) target_splice_sess_cmd_list() - Splice active I/O list from ->sess_cmd_list to ->sess_wait_list, can called with HW fabric lock held. *) target_wait_for_sess_cmds() - Walk ->sess_wait_list waiting on individual ->cmd_wait_comp. Optional transport_wait_for_tasks() call. target_splice_sess_cmd_list() is allowed to be called under HW fabric lock, and performs the splice into se_sess->sess_wait_list and set se_cmd->cmd_wait_set. Then target_wait_for_sess_cmds() walks the list waiting for individual target_put_sess_cmd() fabric callbacks to complete. It also adds TFO->check_release_cmd() to split the completion and memory release calls, where a fabric module uses target_put_sess_cmd() to check for I/O completion during session shutdown. This is currently pushed out into fabric modules as current fabric code may sleep here waiting for TFO->check_stop_free() to complete in main response path, and because target_wait_for_sess_cmds() calling TFO->release_cmd() to free fabric descriptor memory directly. Cc: Christoph Hellwig Cc: Roland Dreier Signed-off-by: Nicholas A. Bellinger --- Reading git-diff-tree failed