From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Date: Fri, 3 Apr 2009 10:28:06 +0000 (+0900)
Subject: [SCSI] sg: fix q->queue_lock on scsi_error_handler path
X-Git-Tag: v2.6.30-rc1~185^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=015640edb1f346e0b2eda703587c4cd1c310ec1d;p=pandora-kernel.git

[SCSI] sg: fix q->queue_lock on scsi_error_handler path

sg_rq_end_io() is called via rq->end_io. In some rare cases,
sg_rq_end_io calls blk_put_request/blk_rq_unmap_user (when a program
issuing a command has gone before the command completion; e.g. by
interrupting a program issuing a command before the command
completes).

We can't call blk_put_request/blk_rq_unmap_user in interrupt so the
commit c96952ed7031e7c576ecf90cf95b8ec099d5295a uses
execute_in_process_context().

The problem is that scsi_error_handler() calls rq->end_io too. We
can't call blk_put_request/blk_rq_unmap_user too in this path (we hold
q->queue_lock).

To avoid the above problem, in these rare cases, this patch always
uses schedule_work() instead of execute_in_process_context().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---

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