Hi Yaniv > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Yaniv Gardi > Sent: Sunday, June 10, 2012 9:49 PM > To: 'S, Venkatraman' > Cc: [email protected]; [email protected] > Subject: RE: [PATCH v6 0/2] *** adding and exposing SANITIZE capability to > the user > space via a unique IOCTL *** > > First, the REQ_SECURE + REQ_DISCARD are used for specific sector/s. SANITIZE > is a > generic command that erase all unmapped sectors. If a lot of sectors, like 4GBytes, have been marked as unmapped, how long will SANITIZE command take to erase all of them? Will it cause a long time delay for other requests?
> Second, secure erase for a specific sector (SECURE TRIM) is no longer > supported. REQ_SECURE can still erase a specific sector in current MMC driver. If the device support SANITIZE, driver will first use ERASE/TRIM command to mark unmapped sectors, and then issue SANITIZE command to erase them. eMMC4.5 specification has said clearly that ERASE/TRIM command can move the mapped host address range to the unmapped host address range. If the device cannot support SANTIZE, driver will use secure erase/trim command directly. > > Anyhow, SANITIZE replaces the need to issue REQ_SECURE as part of the > REQ_DISCARD request. In this way DISCARD request finishes much faster (order > of > magnitude) and thus improves system performance. When the NVM content must > be erased, the user may use SANITIZE to erase all unmapped sectors. > > An example of usage is refurbished devices in which the carrier wants to erase > NVM content (since the user used only DISCARDs), in this case the a SANITIZE > operation will be triggered in the carrier labs from a dedicated application > through > IOCTL that goes directly to the device. Note that no change to the FS is > required for > such operation. I think the usage you posted here is just what REQ_SECURE implemented. REQ_SECURE will first unmapped the mapped host address and then issue SANITIZE command to erase the contents. Thanks Chuanxiao > > Thanks, > Yaniv > > = > -----Original Message----- > = > From: S, Venkatraman [mailto:[email protected]] = > Sent: Friday, June 08, > 2012 > 2:30 PM = > To: Yaniv Gardi = > Cc: [email protected]; > [email protected] = > Subject: Re: [PATCH v6 0/2] *** adding and exposing > SANITIZE capability to = > the user space via a unique IOCTL *** = > = > On > Thu, Jun > 7, 2012 at 8:08 PM, Yaniv Gardi <[email protected]> = > wrote: > = > > *** adding and exposing SANITIZE capability to the user space via a = > > > > unique IOCTL *** = > = > Well, is this really needed ? As I understand, > SANITIZE is > identical to = > REQ_SECURE + REQ_DISCARD. > = > Mapping the device function to an existing attribute is more easy that = > > creating the whole plumbing around SANITIZE, just because it exists. > = > Apart from the IOCTL, it would be useful to find if any file systems want > to = > > use this, and it is any way more friendly than SECURE + DISCARD. > = > > = > > > = > > changes patch v6: > = > > fixed some code review comments > = > > added timeout dependency for CMD6 when issueing the sanitize = > > command. > = > > > = > > changes patch v5: > = > > added BUG_ON() where needed > = > > > = > > changes patch v4: > = > > removed a few debug printouts > = > > > = > > changes patch v3: > = > > split the patch into 2 commits - block and mmc/card added capability = > > > > MMC_CAP2_SANITIZE to mmc controller = > > = > > Yaniv Gardi (2): > = > > block: ioctl support for sanitize in eMMC 4.5 = > > mmc: card: Adding > support for sanitize in eMMC 4.5 = > > = > > block/blk-core.c | 18 > +++++++++-- = > > block/blk-lib.c | 51 > +++++++++++++++++++++++++++++++ = > > block/blk-merge.c | 6 > ++++ = > > block/elevator.c | 41 ++++++++++++++++++++++++- > = > > block/ioctl.c | 9 +++++ > = > > drivers/mmc/card/block.c | 72 = > > > ++++++++++++++++++++++++++++++++------------ > = > > drivers/mmc/card/queue.c | 10 +++++- > = > > include/linux/blk_types.h | 5 ++- > = > > include/linux/blkdev.h | 3 ++ > = > > include/linux/fs.h | 1 + > = > > include/linux/mmc/host.h | 1 + > = > > kernel/trace/blktrace.c | 2 + = > > 12 files changed, 191 > insertions(+), 28 deletions(-) = > > = > > -- = > > 1.7.6 = > > -- = > > Sent > by a > consultant of the Qualcomm Innovation Center, Inc. > = > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora = > > > > Forum = > > -- = > > To unsubscribe from this list: send the line "unsubscribe > linux-mmc" > = > > in the body of a message to [email protected] More = > > majordomo = > > info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
