First, the REQ_SECURE + REQ_DISCARD are used for specific sector/s. SANITIZE is a generic command that erase all unmapped sectors. Second, secure erase for a specific sector (SECURE TRIM) is no longer supported. 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. Thanks, Yaniv = > -----Original Message----- = > From: S, Venkatraman [mailto:svenkatr@xxxxxx] = > Sent: Friday, June 08, 2012 2:30 PM = > To: Yaniv Gardi = > Cc: linux-mmc@xxxxxxxxxxxxxxx; merez@xxxxxxxxxxxxxx = > 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 <ygardi@xxxxxxxxxxxxxx> = > 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 majordomo@xxxxxxxxxxxxxxx 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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
