From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Mon, 13 Apr 2015 14:21:57 +0000 (+0900)
Subject: target/file: Fix SG table for prot_buf initialization
X-Git-Tag: omap-for-v4.2/o2_dc~20^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c836777830428372074d5129ac513e1472c99791;p=pandora-kernel.git

target/file: Fix SG table for prot_buf initialization

In fd_do_prot_rw(), it allocates prot_buf which is used to copy from
se_cmd->t_prot_sg by sbc_dif_copy_prot().  The SG table for prot_buf
is also initialized by allocating 'se_cmd->t_prot_nents' entries of
scatterlist and setting the data length of each entry to PAGE_SIZE
at most.

However if se_cmd->t_prot_sg contains a clustered entry (i.e.
sg->length > PAGE_SIZE), the SG table for prot_buf can't be
initialized correctly and sbc_dif_copy_prot() can't copy to prot_buf.
(This actually happened with TCM loopback fabric module)

As prot_buf is allocated by kzalloc() and it's physically contiguous,
we only need a single scatterlist entry.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---

Reading git-diff-tree failed