From d4223e06b6aed581625f574ad8faa71b6c0fc903 Mon Sep 17 00:00:00 2001 From: George Hilliard Date: Wed, 20 Mar 2019 16:42:05 -0600 Subject: [PATCH] staging: mt7621-mmc: Check for nonzero number of scatterlist entries The buffer descriptor setup loop is correct only if it is setting up at least one bd struct. Besides, there is an error if dma_map_sg() returns 0, which is possible and must be handled. Additionally, remove the BUG_ON() checking sglen, which is unnecessary because we configure DMA with that constraint during init. Signed-off-by: George Hilliard Signed-off-by: Greg Kroah-Hartman --- drivers/staging/mt7621-mmc/sd.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c index ff01872ab972..e346167754bd 100644 --- a/drivers/staging/mt7621-mmc/sd.c +++ b/drivers/staging/mt7621-mmc/sd.c @@ -591,8 +591,6 @@ static void msdc_dma_setup(struct msdc_host *host, struct msdc_dma *dma, struct bd *bd; u32 j; - BUG_ON(sglen > MAX_BD_NUM); /* not support currently */ - gpd = dma->gpd; bd = dma->bd; @@ -681,6 +679,13 @@ static int msdc_do_request(struct mmc_host *mmc, struct mmc_request *mrq) data->sg_count = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len, mmc_get_dma_dir(data)); + + if (data->sg_count == 0) { + dev_err(mmc_dev(host->mmc), "failed to map DMA for transfer\n"); + data->error = -ENOMEM; + goto done; + } + msdc_dma_setup(host, &host->dma, data->sg, data->sg_count);