Avri Altman <Avri.Altman@xxxxxxx> 于2022年10月21日周五 15:53写道：
>
> > From: Wenchao Chen <wenchao.chen@xxxxxxxxxx>
> >
> > This patch introduces host->fua_disable for MMC host controller.
> > The host can turn off FUA to improve performance.
> >
> > Signed-off-by: Wenchao Chen <wenchao.chen@xxxxxxxxxx>
> > ---
> > V1 -> V2
> > Address Chaitanyak's suggestions
> > Address Avri's suggestions
> > ---
> > drivers/mmc/core/block.c | 3 ++-
> > include/linux/mmc/host.h | 3 +++
> > 2 files changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index
> > 54cd009aee50..333e819e077a 100644
> > --- a/drivers/mmc/core/block.c
> > +++ b/drivers/mmc/core/block.c
> > @@ -2490,7 +2490,8 @@ static struct mmc_blk_data
> > *mmc_blk_alloc_req(struct mmc_card *card,
> > ((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||
> > card->ext_csd.rel_sectors)) {
> > md->flags |= MMC_BLK_REL_WR;
> > - fua_enabled = true;
> > + if (!card->host->fua_disable)
> > + fua_enabled = true;
> > cache_enabled = true;
> > }
> > if (mmc_cache_enabled(card->host)) diff --git a/include/linux/mmc/host.h
> > b/include/linux/mmc/host.h index 8fdd3cf971a3..16a5bee3eeae 100644
> > --- a/include/linux/mmc/host.h
> > +++ b/include/linux/mmc/host.h
> > @@ -517,6 +517,9 @@ struct mmc_host {
> > struct blk_crypto_profile crypto_profile; #endif
> >
> > + /* Host FUA support */
> > + bool fua_disable;
> Why do you need to invent a LLD mechanism, when you already have a block api (QUEUE_FLAG_FUA) for that?
> Which is actually misleading, since /sys/block/mmcblk0/queue/fua will still reads 0.
>
> Thanks,
> Avri
>
Hi Avri
The code expands as follows:
static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
struct device *parent,
sector_t size,
bool default_ro,
const char *subname,
int area_type,
unsigned int part_type)
{
...
if (md->flags & MMC_BLK_CMD23 &&
((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||
card->ext_csd.rel_sectors)) {
md->flags |= MMC_BLK_REL_WR;
if (!card->host->fua_disable) <<<Allow chip manufacturers whether to use FUA.
fua_enabled = true;
cache_enabled = true;
}
if (mmc_cache_enabled(card->host))
cache_enabled = true;
blk_queue_write_cache(md->queue.queue, cache_enabled, fua_enabled); <<<
...
}
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
if (wc)
blk_queue_flag_set(QUEUE_FLAG_WC, q);
else
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
if (fua)
blk_queue_flag_set(QUEUE_FLAG_FUA, q); <<<
else
blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
}
Also, echo 0 > fua is forbidden regardless of permissions.
Do you have any better suggestions?
> > +
> > /* Host Software Queue support */
> > bool hsq_enabled;
> >
> > --
> > 2.17.1
>
