Doubt on mmc erase command

Doubt on mmc erase command

[Sheetal]

Hello,

I'm trying to send ERASE Command to the emmc by deleting a file on one 
of the emmc partitions and then doing a sync, But I'm noticing that even 
this will not issue the erase command to emmc.

I did trace the code on, from where this erase command is issued, but my 
trace ended at an ioctl call "do_vfs_ioctl()" more specific 
"SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned 
long, arg)" system call definition does a call to do_vfs_ioctl.

Please help me understand how to initiate this from userspace.

Re: Doubt on mmc erase command

[Ritesh Harjani]

Hi Sheetal,

Try enabling mmc trace events to check what is the cmd you are getting
to confirm erase going through.
You shoud get cmd 35/36/38 if erase is going through in case of emmc.

-Ritesh






On Tue, Feb 10, 2015 at 10:00 PM, Sheetal <sheetal.tigadoli@gmail.com> wrote:
> Hello,
>
> I'm trying to send ERASE Command to the emmc by deleting a file on one of
> the emmc partitions and then doing a sync, But I'm noticing that even this
> will not issue the erase command to emmc.
>
> I did trace the code on, from where this erase command is issued, but my
> trace ended at an ioctl call "do_vfs_ioctl()" more specific
> "SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long,
> arg)" system call definition does a call to do_vfs_ioctl.
>
> Please help me understand how to initiate this from userspace.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Doubt on mmc erase command

[Sheetal]

Hello Ritesh Harjani,

Thanks for the info Ritesh, I'll try out your pointer to mmc trace 
events next time i run into eMMC issue

In the current case, I found out that in case of file deletion, only the 
file's metadata(such as entry in inode table, inode_bitmap and other 
filesystem parameters) is freed and it won't invoke the ERASE command 
seq explicitly(atleast in case of EXT4 it doesn't send ERASE CMD).
I think only in case of formatting(mkfs) of the partition or the whole 
eMMC, ERASE command is issued.

Thanks
Sheetal

On Tuesday 13 October 2015 02:14 PM, Ritesh Harjani wrote:
> Hi Sheetal,
>
> Try enabling mmc trace events to check what is the cmd you are getting
> to confirm erase going through.
> You shoud get cmd 35/36/38 if erase is going through in case of emmc.
>
> -Ritesh
>
>
>
>
>
>
> On Tue, Feb 10, 2015 at 10:00 PM, Sheetal <sheetal.tigadoli@gmail.com> wrote:
>> Hello,
>>
>> I'm trying to send ERASE Command to the emmc by deleting a file on one of
>> the emmc partitions and then doing a sync, But I'm noticing that even this
>> will not issue the erase command to emmc.
>>
>> I did trace the code on, from where this erase command is issued, but my
>> trace ended at an ioctl call "do_vfs_ioctl()" more specific
>> "SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long,
>> arg)" system call definition does a call to do_vfs_ioctl.
>>
>> Please help me understand how to initiate this from userspace.
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html