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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 <thirtythreeforty@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
George Hilliard 2019-03-20 16:42:05 -06:00 committed by Greg Kroah-Hartman
parent f2778bb3cb
commit d4223e06b6
1 changed files with 7 additions and 2 deletions
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9
drivers/staging/mt7621-mmc/sd.c
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@ -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);