[Drbd-dev] [patch 1/2] block, drbd: fix drbd_req_new() initialization
axboe at fb.com
Sun Mar 8 02:03:30 CET 2015
On 03/07/2015 05:53 PM, David Rientjes wrote:
> On Sat, 7 Mar 2015, Jens Axboe wrote:
>>> mempool_alloc() does not support __GFP_ZERO since elements may come from
>>> memory that has already been released by mempool_free().
>>> Remove __GFP_ZERO from mempool_alloc() in drbd_req_new() and properly
>>> initialize it to 0.
>> You should add it to mempool instead, avoid having this issue show up for
>> other folks as well. It'd be trivial to do. Normal ->alloc() should honor
>> __GFP_ZERO, just do the same manually for removing an item from the internal
> Umm, it's not trivial to do and wouldn't make sense to do it. Mempools
Uhm, it would make sense, though.
> don't know the element size, in other words it wouldn't know the length to
> memset() to 0 for mempool_alloc(). It shouldn't be modified to know the
> element size since elements are allocated by the implementation of
> mempool_alloc_t and they could easily become inconsistent. This patch is
> what you want to merge, really.
I forgot we don't have the size in there. Then I would suggest adding a
WARN_ON() for __GFP_ZERO being set in mempool_alloc(), at the very least.
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