From: Michael Wu michael@allwinnertech.com
commit 08ebf903af57cda6d773f3dd1671b64f73b432b8 upstream.
During the card initialization process, the mmc core checks whether the eMMC/SD card supports an internal writeback-cache and then enables it inside the card.
Unfortunately, this isn't according to what the mmc core reports to the upper block layer. Instead, the writeback-cache support with REQ_FLUSH and REQ_FUA, are being enabled depending on whether the host supports the CMD23 (MMC_CAP_CMD23) and whether an eMMC supports the reliable-write command.
This is wrong and it may also sound awkward. In fact, it's a remnant from when both eMMC/SD cards didn't have dedicated commands/support to control the internal writeback-cache. In other words, it was the best we could do at that point in time.
To fix the problem, but also without breaking backwards compatibility, let's align the REQ_FLUSH support with whether the writeback-cache became successfully enabled - for both eMMC and SD cards.
Cc: stable@kernel.org Fixes: 881d1c25f765 ("mmc: core: Add cache control for eMMC4.5 device") Fixes: 130206a615a9 ("mmc: core: Add support for cache ctrl for SD cards") Depends-on: 97fce126e279 ("mmc: block: Issue a cache flush only when it's enabled") Reviewed-by: Avri Altman Avri.Altman@wdc.com Signed-off-by: Michael Wu michael@allwinnertech.com Link: https://lore.kernel.org/r/20220331073223.106415-1-michael@allwinnertech.com [Ulf: Re-wrote the commit message] Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mmc/core/block.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
--- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -2376,6 +2376,8 @@ static struct mmc_blk_data *mmc_blk_allo struct mmc_blk_data *md; int devidx, ret; char cap_str[10]; + bool cache_enabled = false; + bool fua_enabled = false;
devidx = ida_simple_get(&mmc_blk_ida, 0, max_devices, GFP_KERNEL); if (devidx < 0) { @@ -2457,13 +2459,17 @@ static struct mmc_blk_data *mmc_blk_allo md->flags |= MMC_BLK_CMD23; }
- if (mmc_card_mmc(card) && - md->flags & MMC_BLK_CMD23 && + 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; - blk_queue_write_cache(md->queue.queue, true, true); + 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);
string_get_size((u64)size, 512, STRING_UNITS_2, cap_str, sizeof(cap_str));