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authorJiong Wu <lohengrin1024@gmail.com>2019-03-01 00:18:33 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-03-23 20:09:57 +0100
commit6bd9959aa110af7c10e698ab7720026c6b178921 (patch)
treead968449928bf3f7606e55e2332ffd4487eb30eb /drivers/mmc
parent2946910ed8377100a3f23a558a8bc8fd83d0302a (diff)
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mmc:fix a bug when max_discard is 0
commit d4721339dcca7def04909a8e60da43c19a24d8bf upstream. The original purpose of the code I fix is to replace max_discard with max_trim if max_trim is less than max_discard. When max_discard is 0 we should replace max_discard with max_trim as well, because max_discard equals 0 happens only when the max_do_calc_max_discard process is overflowed, so if mmc_can_trim(card) is true, max_discard should be replaced by an available max_trim. However, in the original code, there are two lines of code interfere the right process. 1) if (max_discard && mmc_can_trim(card)) when max_discard is 0, it skips the process checking if max_discard needs to be replaced with max_trim. 2) if (max_trim < max_discard) the condition is false when max_discard is 0. it also skips the process that replaces max_discard with max_trim, in fact, we should replace the 0-valued max_discard with max_trim. Signed-off-by: Jiong Wu <Lohengrin1024@gmail.com> Fixes: b305882fbc87 (mmc: core: optimize mmc_calc_max_discard) Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/core/core.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index d4f9bfbaf023..6600b3466dfb 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2378,9 +2378,9 @@ 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 (max_discard && mmc_can_trim(card)) {
+ if (mmc_can_trim(card)) {
max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG);
- if (max_trim < max_discard)
+ if (max_trim < max_discard || max_discard == 0)
max_discard = max_trim;
} else if (max_discard < card->erase_size) {
max_discard = 0;