Re: [PATCH 1/2] target/file: walk properly over sg list

["Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx>]

On Mon, 2011-11-28 at 12:50 +0100, Sebastian Andrzej Siewior wrote:
> On 11/28/2011 12:47 PM, Nicholas A. Bellinger wrote:
> 
> > Note that IBLOCK and PSCSI are already using for_each_sg when walking
> > task->task_sg memory, and making FILEIO do this as well is what we
> > should be doing.  However, I'm curious what your use-case was to trigger
> > this with fileio, as we don't expect a single task to ever use chained
> > sg in order to trigger this bug..?
> >
> 
> This script:
> 
> #!/bin/sh
> modprobe target_core_mod
> mount a -t configfs /sys/kernel/config
> 
> CONFIGFS=/sys/kernel/config/
> TARGET=/sys/kernel/config/target/core/
> export FABRIC=/sys/kernel/config/target/loopback/
> 
> mkdir -p $TARGET/fileio_0/fileio
> echo "fd_dev_name=/root/file.bin,fd_dev_size=31457280" > 
> $TARGET/fileio_0/fileio/control
> echo 1 > $TARGET/fileio_0/fileio/enable
> 
> mkdir -p $FABRIC/naa.6001405c3214b06a/tpgt_1
> mkdir $FABRIC/naa.6001405c3214b06a/tpgt_1/lun/lun_0
> echo naa.6001405c3214b06b > $FABRIC/naa.6001405c3214b06a/tpgt_1/nexus
> 
> ln -sv $TARGET/fileio_0/fileio 
> $FABRIC/naa.6001405c3214b06a/tpgt_1/lun/lun_0/virtual_scsi_port
> 
> 
> followed by
> - cfdiks /dev/sda (make 1 partition)
> - mkfs.ext2 /dev/sda
> 
> > Is this with a manually set small max_sectors fileio backend, or a
> > limited block_device max_sectors with fileio that would cause>  1 task
> > allocation to occur on your setup..?
> 
> Just the script I mentioned plus the two commands afterwords. The crash
> happens during mkfs.ext2
> 

Ok, so no special max_sectors with fileio.  I'll take a look at this
with loopback LUNs later today.

Thanks,

--nab

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