On 4/16/2015 6:58 PM, Sagi Grimberg wrote:
On 4/16/2015 4:46 PM, Akinobu Mita wrote:
2015-04-16 17:52 GMT+09:00 Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx>:
On 4/15/2015 7:10 PM, Martin K. Petersen wrote:
"Sagi" == Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx> writes:
By the commit 436f4a0a ("loopback: Add fabric_prot_type attribute
support"), When WRITE_SAME command with WRPROTECT=0 is executed,
sbc_dif_generate() is called but cmd->t_prot_sg is NULL as block
layer didn't allocate it for WRITE_SAME.
Sagi> Actually this is a bug. Why didn't the initiator allocate
Sagi> integrity meta-data for WRITE_SAME? Looking at the code it looks
Sagi> like it should.
We don't issue WRITE SAME with PI so there is no prot SGL.
Is there a specific reason why we don't?
It is not only for the WRITE SAME requests from block device but
also for READ/WRITE with PROTECT=0 requests by SG_IO.
This is specific to loopback which is using target_submit_cmd_map_sgls()
Other fabrics would allocate sgls per IO and the core would allocate
protection SGLs as well.
By "This" I meant the NULL deref you are witnessing in for wrprotect=0.
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