From 427b00342c5a3ebcf31fac2ce3b21fb993952816 Mon Sep 17 00:00:00 2001 From: Yoshihiro Shimoda Date: Thu, 12 Sep 2019 13:13:55 +0900 Subject: [PATCH] mmc: queue: Fix bigger segments usage The commit 38c38cb73223 ("mmc: queue: use bigger segments if DMA MAP layer can merge the segments") always enables the bugger segments if DMA MAP layer can merge the segments, but some controllers (SDHCI) have strictly limitation about the segments size, and then the commit breaks on the controllers. To fix the issue, this patch adds a new flag MMC_CAP2_MERGE_CAPABLE into the struct mmc_host and the bigger segments usage is disabled as default. Reported-by: Thierry Reding Fixes: 38c38cb73223 ("mmc: queue: use bigger segments if DMA MAP layer can merge the segments") Signed-off-by: Yoshihiro Shimoda Acked-by: Ulf Hansson Signed-off-by: Christoph Hellwig --- drivers/mmc/core/queue.c | 8 +++++++- include/linux/mmc/host.h | 1 + 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index 1e29b305767e..9edc08685e86 100644 --- a/drivers/mmc/core/queue.c +++ b/drivers/mmc/core/queue.c @@ -399,6 +399,11 @@ static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card) init_waitqueue_head(&mq->wait); } +static inline bool mmc_merge_capable(struct mmc_host *host) +{ + return host->caps2 & MMC_CAP2_MERGE_CAPABLE; +} + /* Set queue depth to get a reasonable value for q->nr_requests */ #define MMC_QUEUE_DEPTH 64 @@ -441,7 +446,8 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card) * the host->can_dma_map_merge should be set before to get max_segs * from mmc_get_max_segments(). */ - if (host->max_segs < MMC_DMA_MAP_MERGE_SEGMENTS && + if (mmc_merge_capable(host) && + host->max_segs < MMC_DMA_MAP_MERGE_SEGMENTS && dma_get_merge_boundary(mmc_dev(host))) host->can_dma_map_merge = 1; else diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index c5662b3e64db..3becb28210f3 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -367,6 +367,7 @@ struct mmc_host { #define MMC_CAP2_CQE (1 << 23) /* Has eMMC command queue engine */ #define MMC_CAP2_CQE_DCMD (1 << 24) /* CQE can issue a direct command */ #define MMC_CAP2_AVOID_3_3V (1 << 25) /* Host must negotiate down from 3.3V */ +#define MMC_CAP2_MERGE_CAPABLE (1 << 26) /* Host can merge a segment over the segment size */ int fixed_drv_type; /* fixed driver type for non-removable media */