mmc: queue: bring discard_granularity/alignment into line with SCSI

SCSI defines discard alignment as the offset to the first
optimal discard.  In the case of SD/MMC, that is always zero
which is the default.

SCSI defines discard granularity as a hint of a optimal
discard size.  That is much better expressed by the MMC
"preferred erase size" (pref_erase) field.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Adrian Hunter 2011-06-23 13:40:29 +03:00 committed by Chris Ball
parent d09408ade0
commit c31b55cd4e

View file

@ -135,12 +135,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
mq->queue->limits.max_discard_sectors = UINT_MAX;
if (card->erased_byte == 0)
mq->queue->limits.discard_zeroes_data = 1;
if (!mmc_can_trim(card) && is_power_of_2(card->erase_size)) {
mq->queue->limits.discard_granularity =
card->erase_size << 9;
mq->queue->limits.discard_alignment =
card->erase_size << 9;
}
mq->queue->limits.discard_granularity = card->pref_erase << 9;
if (mmc_can_secure_erase_trim(card))
queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD,
mq->queue);