On 2018/2/9 1:41, Sergio Valverde wrote:
If the max_discard value is zero, the conditional branch that checks the
trim capabilities will never update this value with max_trim.
Change the condition statement to also check the max_discard value in order
to avoid an unnecessary call to mmc_do_calc_max_discard.
Given it's not in the hot call patch and it's rare to return zero from
mmc_do_calc_max_discard if you read the code instead of doing sanity
check by tools. So I doubt there is no gain in practice. But FWIW,
Reviewed-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxx>
Signed-off-by: Sergio Valverde <vlvrdv@xxxxxxxxx>
---
Changes in v2:
- Evaluate max_discard to avoid unnecessary calls to mmc_can_trim.
drivers/mmc/core/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 1f0f44f..c32c0f4 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2567,7 +2567,7 @@ unsigned int mmc_calc_max_discard(struct mmc_card *card)
return card->pref_erase;
max_discard = mmc_do_calc_max_discard(card, MMC_ERASE_ARG);
- if (mmc_can_trim(card)) {
+ if (max_discard && mmc_can_trim(card)) {
max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG);
if (max_trim < max_discard)
max_discard = max_trim;
--
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