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Message-ID: <49942A9E.8090405@panasas.com>
Date: Thu, 12 Feb 2009 15:56:46 +0200
From: Boaz Harrosh <bharrosh@...asas.com>
To: jens.axboe@...cle.com, James.Bottomley@...senPartnership.com,
FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
CC: linux-scsi@...r.kernel.org,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [RFC] block: Don't let blk_put_request leak BIOs
Boaz Harrosh wrote:
> Boaz Harrosh wrote:
>> If a block ULD had allocated a request and mapped some memory into it,
>> using one of blk_rq_map_xxx routines, but then for some reason failed to
>> execute the request through one of the blk_execute_request routines.
>> Then the associated BIO would leak, unless ULD resorts to low-level loops
>> intimate of block internals.
>>
>> [RFC]
>> This code will also catch situations where LLD failed to complete
>> the request before aborting it. Such situations are a BUG. Should we
>> use WARN_ON_ONCE() in that case. The situation above is possible and
>> can happen normally in memory pressure situations so maybe we should
>> devise a bit-flag that ULD denotes that the request was aborted and
>> only WARN_ON if flag was not set.
>>
>> I'm sending this before any-tests so people can comment on possible
>> pitfalls.
>>
>> Signed-off-by: Boaz Harrosh <bharrosh@...asas.com>
>> ---
>
> I've booted a Linux PC with lots of sata disks, connected an iscsi
> target, ran OSD tests. It looks like it's working which means
> request->bio is set to NULL after it is used in the regular path.
>
> This needs to sit in Linux next and be tested for a long while.
>
> Jens I'll be waiting for your comment and will send a proper
> patch for the block bits. We will have to time this with James
> to see when the OSD bits can be submitted after that, then TOMO's
> patch for un-exporting blk_req_append_bio can be merged. Or maybe
> it can all go in one patch through scsi?
>
> Thanks
> Boaz
Spock to soon this patch is shit, I'll look into it
Sorry for the noise
Boaz
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