> 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));
> }
Ahha - ok.
Thanks for clarifying this.
>
> Also, echo 0 > fua is forbidden regardless of permissions.
> Do you have any better suggestions?
No - I see what you mean now.
Looks good to me.
Thanks,
Avri
>
> > > +
> > > /* Host Software Queue support */
> > > bool hsq_enabled;
> > >
> > > --
> > > 2.17.1
> >
