From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Fri, 20 May 2011 03:19:09 +0000 (-0700)
Subject: target: Fix multi task->task_sg[] chaining logic bug
X-Git-Tag: v2.6.39.1~95
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4d195fe897027ee3da1bd89b5a25631ebb7da6a;p=pandora-kernel.git

target: Fix multi task->task_sg[] chaining logic bug

commit 97868c8905a1537153d406c4a3aa39a503a5c299 upstream.

This patch fixes a bug in transport_do_task_sg_chain() used by HW target
mode modules with sg_chain() to provide a single sg_next() walkable memory
layout for use with pci_map_sg() and friends.  This patch addresses an
issue with mapping multiple small block max_sector tasks across multiple
struct se_task->task_sg[] mappings for HW target mode operation.

This was causing OOPs with (cmd->t_task->t_tasks_no > 1) I/O traffic for
HW target drivers using transport_do_task_sg_chain(), and has been tested
so far with tcm_fc(openfcoe), tcm_qla2xxx, and ib_srpt fabrics with
t_tasks_no > 1 IBLOCK backends using a smaller max_sectors to trigger the
original issue.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: Kiran Patil <kiran.patil@intel.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

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