Re: [Nbd] [PATCH 2/8] mmc: fix max_discard_sectors
- To: Adrian Hunter <adrian.hunter@...1303...>
- Cc: axboe@...161..., nbd-general@lists.sourceforge.net, Vivek Trivedi <t.vivek@...1329...>, npiggin@...161..., neilb@...122..., dwmw2@...1270..., Paul.Clements@...124..., linux-kernel@...25..., linux-raid@...25..., Namjae Jeon <namjae.jeon@...1329...>, linux-mtd@...1331..., linux-mmc@...25..., cjb@...1330..., shli@...1285...
- Subject: Re: [Nbd] [PATCH 2/8] mmc: fix max_discard_sectors
- From: Namjae Jeon <linkinjeon@...17...>
- Date: Mon, 15 Apr 2013 16:52:54 +0900
- Message-id: <CAKYAXd8EPHoeKY3GUZof+uzHRQ78EW68DuJfjKx=xXs45uYkOQ@...18...>
- In-reply-to: <516BAA36.9030500@...1303...>
- References: <1365860309-21261-1-git-send-email-linkinjeon@...17...> <516BAA36.9030500@...1303...>
2013/4/15, Adrian Hunter <adrian.hunter@...1303...>:
> On 13/04/13 16:38, Namjae Jeon wrote:
>> From: Namjae Jeon <namjae.jeon@...1329...>
>>
>> https://lkml.org/lkml/2013/4/1/292
>> As per above discussion, there is possibility that request's __data_len
>> field may overflow when max_discard_sectors greater than UINT_MAX >> 9
>>
>> If multiple discard requests get merged, merged discard request's
>> size exceeds 4GB, there is possibility that merged discard request's
>> __data_len field may overflow.
>>
>> This patch fixes this issue.
>>
>> Reported-by: Max Filippov <jcmvbkbc@...17...>
>> Signed-off-by: Namjae Jeon <namjae.jeon@...1329...>
>> Signed-off-by: Vivek Trivedi <t.vivek@...1329...>
>> Tested-by: Max Filippov <jcmvbkbc@...17...>
>> ---
>> drivers/mmc/card/queue.c | 2 +-
>> drivers/mmc/core/core.c | 4 ++--
>> 2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
>> index 9447a0e..54726b7 100644
>> --- a/drivers/mmc/card/queue.c
>> +++ b/drivers/mmc/card/queue.c
>> @@ -166,7 +166,7 @@ static void mmc_queue_setup_discard(struct
>> request_queue *q,
>> return;
>>
>> queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
>> - q->limits.max_discard_sectors = max_discard;
>> + blk_queue_max_discard_sectors(q, max_discard);
>> if (card->erased_byte == 0 && !mmc_can_discard(card))
>> q->limits.discard_zeroes_data = 1;
>> q->limits.discard_granularity = card->pref_erase << 9;
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index 7b435a3..6ee530c 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -2058,7 +2058,7 @@ static unsigned int mmc_do_calc_max_discard(struct
>> mmc_card *card,
>> if (card->erase_shift)
>> max_qty = UINT_MAX >> card->erase_shift;
>> else if (mmc_card_sd(card))
>> - max_qty = UINT_MAX;
>> + max_qty = UINT_MAX >> 9;
>
> No. This function calculates max discard for the card not the block layer.
> Apply the block layer limitation at the block layer interface e.g.
> in mmc_queue_setup_discard()
Hi Adrian,
Okay, I will remove change in mmc_do_calc_max_discard and mmc_calc_max_discard.
>> @@ -166,7 +166,7 @@ static void mmc_queue_setup_discard(struct
>> request_queue *q,
>> return;
>>
>> queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
>> - q->limits.max_discard_sectors = max_discard;
>> + blk_queue_max_discard_sectors(q, max_discard);
>> if (card->erased_byte == 0 && !mmc_can_discard(card))
>> q->limits.discard_zeroes_data = 1;
Above change will handle max discard sectors as we have updated
blk_queue_max_discard_sectors to check upper limit of max discard
sectors as UINT_MAX >> 9.
Thanks.
>
>> else
>> max_qty = UINT_MAX / card->erase_size;
>>
>> @@ -2100,7 +2100,7 @@ unsigned int mmc_calc_max_discard(struct mmc_card
>> *card)
>> unsigned int max_discard, max_trim;
>>
>> if (!host->max_discard_to)
>> - return UINT_MAX;
>> + return UINT_MAX >> 9;
>
> Ditto.
>
>>
>> /*
>> * Without erase_group_def set, MMC erase timeout depends on clock
>>
>
>
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