Re: [Nbd] [PATCH 2/8] mmc: fix max_discard_sectors
- To: Namjae Jeon <linkinjeon@...17...>
- 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: Adrian Hunter <adrian.hunter@...1303...>
- Date: Mon, 15 Apr 2013 10:20:22 +0300
- Message-id: <516BAA36.9030500@...1303...>
- In-reply-to: <1365860309-21261-1-git-send-email-linkinjeon@...17...>
- References: <1365860309-21261-1-git-send-email-linkinjeon@...17...>
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()
> 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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