From e7b42769ee291c7993bff392e37a768df46dabac Mon Sep 17 00:00:00 2001 From: Shawn Lin Date: Wed, 23 Aug 2017 15:38:31 +0800 Subject: [PATCH] mmc: block: cast a informative log for no devidx available The intention for this patch is to help folks debug the failure like this: dwmmc_rockchip fe320000.dwmmc: IDMAC supports 32-bit address mode. dwmmc_rockchip fe320000.dwmmc: Using internal DMA controller. dwmmc_rockchip fe320000.dwmmc: Version ID is 270a dwmmc_rockchip fe320000.dwmmc: DW MMC controller at irq 28,32 bit host data width,256 deep fifo dwmmc_rockchip fe320000.dwmmc: Got CD GPIO mmc_host mmc0: Bus speed (slot 0) = 400000Hz (slot req 400000Hz, actual 400000HZ div = 0) mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 50000000Hz, actual 50000000HZ div = 0) mmc0: new high speed SDHC card at address 0007 mmcblk: probe of mmc0:0007 failed with error -28 The reason may be some buggy userspace daemon miss the disk remove uevent sometimes so it would finally make the SD card not work. So from the dmesg it only shows a errno of -28 but still don't understand what happened. For quick reproduce this, we could set max_devices to 8 and run for i in $(seq 1 9); do echo "========================" $i echo fe320000.dwmmc > /sys/bus/platform/drivers/dwmmc_rockchip/unbind sleep .5 echo fe320000.dwmmc > /sys/bus/platform/drivers/dwmmc_rockchip/bind sleep .5 mount -t vfat /dev/mmcblk0 /mnt sleep .5 done Another possible reason would be the device has more partitions than what we support, so that they have to increase their max_devices. Signed-off-by: Shawn Lin Signed-off-by: Ulf Hansson --- drivers/mmc/core/block.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 0eebc2f726c3..b95c3b0094fd 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -2034,8 +2034,20 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, int devidx, ret; devidx = ida_simple_get(&mmc_blk_ida, 0, max_devices, GFP_KERNEL); - if (devidx < 0) + if (devidx < 0) { + /* + * We get -ENOSPC because there are no more any available + * devidx. The reason may be that, either userspace haven't yet + * unmounted the partitions, which postpones mmc_blk_release() + * from being called, or the device has more partitions than + * what we support. + */ + if (devidx == -ENOSPC) + dev_err(mmc_dev(card->host), + "no more device IDs available\n"); + return ERR_PTR(devidx); + } md = kzalloc(sizeof(struct mmc_blk_data), GFP_KERNEL); if (!md) { -- 2.20.1