From: Tony Battersby <tonyb@cybernetics.com>
Date: Tue, 20 Jan 2009 22:00:09 +0000 (-0500)
Subject: [SCSI] sg: fix races with ioctl(SG_IO)
X-Git-Tag: v2.6.30-rc1~641^2~97
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a2dd3b4cea335713b58996bb07b3abcde1175f47;p=pandora-kernel.git

[SCSI] sg: fix races with ioctl(SG_IO)

sg_io_owned needs to be set before the command is sent to the midlevel;
otherwise, a quickly-completing command may cause a different CPU
to see "srp->done == 1 && !srp->sg_io_owned", which would lead to
incorrect behavior.

Check srp->done and set srp->orphan while holding rq_list_lock to
prevent races with sg_rq_end_io().

There is no need to check sfp->closed from read/write/ioctl/poll/etc.
since the kernel guarantees that this won't happen.

The usefulness of sg_srp_done() was questionable before; now it is
definitely not needed.

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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