possible bug using async_xor() call in ops_run_post_xor()

2 messages, 2 authors, 2008-07-25 · open the first message on its own page

possible bug using async_xor() call in ops_run_post_xor()

From: tirumalareddy marri <hidden>
Date: 2008-07-25 18:45:21

I am looking at async_xor() usage and found that if async_xor() returns null because of  device->device_prep_dma_xor() <async_xor.c> failed to get slot. This might cause failure of stripe creation . Which would cause data corruption in RAID-5 at high data rates.
OR
Data integrity is guaranteed because ops_complete_write() will not be called in the event of  device->device_prep_dma_xor() failed to get slot and returned NULL ? 
Thanks,
Marri
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Re: possible bug using async_xor() call in ops_run_post_xor()

From: Dan Williams <hidden>
Date: 2008-07-25 19:47:27

On Fri, Jul 25, 2008 at 11:45 AM, tirumalareddy marri
[off-list ref] wrote:
I am looking at async_xor() usage and found that if async_xor() returns null because of  device->device_prep_dma_xor() <async_xor.c> failed to get slot. This might cause failure of stripe creation . Which would cause data corruption in RAID-5 at high data rates.
OR
Data integrity is guaranteed because ops_complete_write() will not be called in the event of  device->device_prep_dma_xor() failed to get slot and returned NULL ?
Hi Marri,

ops_complete_write will be called regardless of whether NULL is
returned.  If async_xor returns NULL it simply indicates to the caller
that the operation was completed synchronously.  In current mainline
async_xor will poll for a descriptor so the driver must take care to
ensure forward progress.

--
Dan
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