> -----Original Message----- > From: Hunter, Adrian > Sent: Monday, May 21, 2012 7:06 PM > To: Dong, Chuanxiao > Cc: [email protected]; [email protected] > Subject: Re: [PATCH]mmc: core: not to --qty when calculate timeout for > SECURE_ERASE > > On 13/04/12 07:19, Chuanxiao Dong wrote: > > --qty when calculating erase timeout for trim/erase & secure > > trim/erase can prevent the erase range crossing qty+1 erase groups, > > which made the final timeout value is too large for the host. > > > > When operate SECURE_ERASE, driver needs the erase range is aligned > > with erase size, otherwise do nothing and return an error. That is to > > say it is not necessary for SECURE_ERASE to --qty since it will never > > cross an erase group. > > > > Signed-off-by: Chuanxiao Dong <[email protected]> > > --- > > drivers/mmc/core/core.c | 9 ++++++++- > > 1 files changed, 8 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index > > e541efb..b5a393a 100644 > > --- a/drivers/mmc/core/core.c > > +++ b/drivers/mmc/core/core.c > > @@ -1761,7 +1761,7 @@ static unsigned int mmc_do_calc_max_discard(struct > mmc_card *card, > > if (!qty) > > return 0; > > > > - if (qty == 1) > > + if (qty == 1 && arg != MMC_SECURE_ERASE_ARG) > > return 1; > > arg is never MMC_SECURE_ERASE_ARG > > > > > /* Convert qty to sectors */ > > @@ -1772,6 +1772,13 @@ static unsigned int mmc_do_calc_max_discard(struct > mmc_card *card, > > else > > max_discard = --qty * card->erase_size; > > > > + /* > > + * since SECURE_ERASE is erase group aligned, otherwise > > + * it cannot be erased in secure purpose, needn't --qty > > + */ > > + if (arg == MMC_SECURE_ERASE_ARG) > > + max_discard += card->erase_size; > > + > > return max_discard; > > } > > > > What about: > > From: Adrian Hunter <[email protected]> > Date: Mon, 21 May 2012 13:32:42 +0300 > Subject: [PATCH] mmc: core: fix max_discard calculation > > The maximum discard calculation was unnecessarily pessimistic in the case of > erasing entire erase groups. In that case, the quantity does not need to be > decreased by 1 to allow for misalignment because the erasure is always > aligned to > whole erase groups. > > Signed-off-by: Adrian Hunter <[email protected]> > --- > drivers/mmc/core/core.c | 22 +++++++++++++++++----- > 1 files changed, 17 insertions(+), 5 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index > 0b6141d..36bfdce 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -1742,7 +1742,7 @@ static unsigned int mmc_do_calc_max_discard(struct > mmc_card *card, { > struct mmc_host *host = card->host; > unsigned int max_discard, x, y, qty = 0, max_qty, timeout; > - unsigned int last_timeout = 0; > + unsigned int last_timeout = 0, aligned_qty; > > if (card->erase_shift) > max_qty = UINT_MAX >> card->erase_shift; @@ -1769,16 +1769,28 @@ > static unsigned int mmc_do_calc_max_discard(struct mmc_card *card, > if (!qty) > return 0; > > - if (qty == 1) > - return 1; > + if (arg & MMC_TRIM_ARGS) { > + /* > + * The requested number of sectors may not be aligned to an > + * erase group, so we have to decrease the quantity by 1 (unless > + * it is 1) e.g. trimming 2 sectors could cause 2 erase groups > + * to be affected even though 2 sectors is less than the size of > + * 1 erase group. > + */ > + if (qty == 1) > + return 1; > + aligned_qty = qty - 1; > + } else { > + aligned_qty = qty; > + } > > /* Convert qty to sectors */ > if (card->erase_shift) > - max_discard = --qty << card->erase_shift; > + max_discard = aligned_qty << card->erase_shift; > else if (mmc_card_sd(card)) > max_discard = qty; > else > - max_discard = --qty * card->erase_size; > + max_discard = aligned_qty * card->erase_size; > > return max_discard; > }
Hi Hunter, Your patch looks good to me. Since you also mentioned that the arg will never be MMC_SECURE_ERASE_ARG, I want to know why not calculate erase size for secure trim/erase operations? As specification said, secure trim/erase operations has different timeout value with trim/erase. Thanks Chuanxiao -- 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
