On 17 May 2012 09:04, Namjae Jeon <linkinjeon@xxxxxxxxx> wrote:
> 2012/5/17, Saugata Das <saugata.das@xxxxxxxxxx>:
>> On 17 May 2012 06:35, Namjae Jeon <linkinjeon@xxxxxxxxx> wrote:
>>> 2012/5/17, Saugata Das <saugata.das@xxxxxxxxxxxxxx>:
>>>> From: Saugata Das <saugata.das@xxxxxxxxxx>
>>>>
>>>> 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 <saugata.das@xxxxxxxxxx>
>>>> ---
>>>> 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)
>>
>>>> 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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