On 17 May 2012 10:17, Saugata Das <[email protected]> wrote:
> On 17 May 2012 09:04, Namjae Jeon <[email protected]> wrote:
>> 2012/5/17, Saugata Das <[email protected]>:
>>> On 17 May 2012 06:35, Namjae Jeon <[email protected]> wrote:
>>>> 2012/5/17, Saugata Das <[email protected]>:
>>>>> From: Saugata Das <[email protected]>
>>>>>
>>>>> This patch adds the support for large sector size of 4KB by disabling
>>>>> emulation.
>>>>> This patch passes eMMC DATA_SECTOR_SIZE as the logical block size during
>>>>> mmc_blk_alloc_req.
>>>>>
>>>>> In order to use this patch for 4KB sector size, ensure that
>>>>> USE_NATIVE_SECTOR
>>>>> is enabled, partition table is 4KB sector size aligned and file system
>>>>> block
>>>>> size is 4KB.
>>>> If you change native 4K from 512B emulation, filesystem sector size is
>>>> also 4KB align as well block size.
>>>> because default block size of most of filesystem is 4KB, but
>>>> filesystem sector size is 512B,
>>>> So filesystem corruption can be occured on native 4K device.
>>>>>
>>>
>>> I have tested ext4 with 4KB block size and I did not see an instance
>>> where it requested 512B.
>> -> yes, you can not see it, because when formating parittion, sector
>> size is set to 4K by I/O topology. As you know, several filesystems
>> can be used on eMMC not only Ext4. You should mention filesystem
>> sector size align in changelog.
>
> I will add the remark that file system block and sector size should be
> 4KB multiple.
>
>>> For sure, if someone is using file system with 512B sector on eMMC
>>> then the USE_NATIVE_SECTOR should not be enabled.
>> -> it will be the reason about below my question.
>>>
>>> The idea behind the patch is, MMC driver should notify the sector size
>>> information in a generic manner to file system. So, we depend here on
>>> ext_csd.data_sector_size, which should work in both 512B and 4KB case.
>>>
>>>
>>>>> Signed-off-by: Saugata Das <[email protected]>
>>>>> ---
>>>>> drivers/mmc/card/block.c | 16 ++++++++++++++--
>>>>> drivers/mmc/core/mmc.c | 2 ++
>>>>> 2 files changed, 16 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>>>> index 91cda75..b4d0eb1 100644
>>>>> --- a/drivers/mmc/card/block.c
>>>>> +++ b/drivers/mmc/card/block.c
>>>>> @@ -1284,7 +1284,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue
>>>>> *mq,
>>>>> struct request *rqc)
>>>>> int ret = 1, disable_multi = 0, retry = 0, type;
>>>>> enum mmc_blk_status status;
>>>>> struct mmc_queue_req *mq_rq;
>>>>> - struct request *req;
>>>>> + struct request *req = rqc;
>>>>> struct mmc_async_req *areq;
>>>>>
>>>>> if (!rqc && !mq->mqrq_prev->req)
>>>>> @@ -1292,6 +1292,14 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue
>>>>> *mq,
>>>>> struct request *rqc)
>>>>>
>>>>> do {
>>>>> if (rqc) {
>>>>> +
>>>>> + /*
>>>>> + * When 4KB native sector is enabled, single
>>>>> block
>>>>> + * read or write is not allowed
>>>>> + */
>>>>> + if ((brq->data.blocks == 1) &&
>>>>> + (card->ext_csd.data_sector_size == 4096))
>>>>> + goto cmd_abort;
>>>> Why did you add this
>>>> code in any case ?
>>>>
>>>
>>> This was pointed during the previous review that with 4KB sector mode,
>>> 512B transfer is not allowed. So, this check has been added here.
>> -> I think that you should add error log to inform user error case.
>
> I will add pr_err here. I will also modify the condition
> (brq->data.blocks == 1) to
> (brq->data.blocks % 4)
>
Oops. It will be (brq->data.blocks % 8)
>
>>>
>>>>> mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
>>>>> areq = &mq->mqrq_cur->mmc_active;
>>>>> } else
>>>>> @@ -1539,7 +1547,11 @@ static struct mmc_blk_data
>>>>> *mmc_blk_alloc_req(struct
>>>>> mmc_card *card,
>>>>> snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
>>>>> "mmcblk%d%s", md->name_idx, subname ? subname : "");
>>>>>
>>>>> - blk_queue_logical_block_size(md->queue.queue, 512);
>>>>> + if (mmc_card_mmc(card))
>>>>> + blk_queue_logical_block_size(md->queue.queue,
>>>>> + card->ext_csd.data_sector_size);
>>>>> + else
>>>>> + blk_queue_logical_block_size(md->queue.queue, 512);
>>>>> set_capacity(md->disk, size);
>>>>>
>>>>> if (mmc_host_cmd23(card->host)) {
>>>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>>>> index 7268c26..11444c6 100644
>>>>> --- a/drivers/mmc/core/mmc.c
>>>>> +++ b/drivers/mmc/core/mmc.c
>>>>> @@ -516,6 +516,8 @@ static int mmc_read_ext_csd(struct mmc_card *card,
>>>>> u8
>>>>> *ext_csd)
>>>>> } else {
>>>>> card->ext_csd.data_tag_unit_size = 0;
>>>>> }
>>>>> + } else {
>>>>> + card->ext_csd.data_sector_size = 512;
>>>>> }
>>>>>
>>>>> out:
>>>>> --
>>>>> 1.7.4.3
>>>>>
>>>>> --
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>>>>>
>>>
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