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dmaengine: ti-dma-crossbar: Fix possible race condition with dma_inuse

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When looking for unused xbar_out lane we should also protect the set_bit()
call with the same mutex to protect against concurrent threads picking the
same ID.

Fixes: ec9bfa1e1a ("dmaengine: ti-dma-crossbar: dra7: Use bitops instead of idr")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: stable@vger.kernel.org
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Peter Ujfalusi 2017-09-21 14:35:32 +03:00 committed by Vinod Koul
parent 87a2f622cc
commit 2ccb4837c9
1 changed files with 2 additions and 1 deletions
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3
drivers/dma/ti-dma-crossbar.c
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@ -262,13 +262,14 @@ static void *ti_dra7_xbar_route_allocate(struct of_phandle_args *dma_spec,
mutex_lock(&xbar->mutex); mutex_lock(&xbar->mutex);
map->xbar_out = find_first_zero_bit(xbar->dma_inuse, map->xbar_out = find_first_zero_bit(xbar->dma_inuse,
xbar->dma_requests); xbar->dma_requests);
mutex_unlock(&xbar->mutex);
if (map->xbar_out == xbar->dma_requests) { if (map->xbar_out == xbar->dma_requests) {
mutex_unlock(&xbar->mutex);
dev_err(&pdev->dev, "Run out of free DMA requests\n"); dev_err(&pdev->dev, "Run out of free DMA requests\n");
kfree(map); kfree(map);
return ERR_PTR(-ENOMEM); return ERR_PTR(-ENOMEM);
} }
set_bit(map->xbar_out, xbar->dma_inuse); set_bit(map->xbar_out, xbar->dma_inuse);
mutex_unlock(&xbar->mutex);
map->xbar_in = (u16)dma_spec->args[0]; map->xbar_in = (u16)dma_spec->args[0];