dmaengine: increment privatecnt when using dma_get_any_slave_channel

christopherpfreeman · Vinod Koul · commit 63f89caad0e3 · 2015-04-29T16:47:57.000+05:30
Channels allocated via dma_get_any_slave_channel were not increasing
the counter tracking private allocations.  When these channels were
released, privatecnt may erroneously fall to zero.  The DMA device
would then lose its DMA_PRIVATE cap and fail to allocate future private
channels (via private_candidate) as any allocations still outstanding
would incorrectly be seen as public allocations.

Signed-off-by: Christopher Freeman &lt;cfreeman@nvidia.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
@@ -571,11 +571,15 @@ struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
 
 	chan = private_candidate(&mask, device, NULL, NULL);
 	if (chan) {
+		dma_cap_set(DMA_PRIVATE, device->cap_mask);
+		device->privatecnt++;
 		err = dma_chan_get(chan);
 		if (err) {
 			pr_debug("%s: failed to get %s: (%d)\n",
 				__func__, dma_chan_name(chan), err);
 			chan = NULL;
+			if (--device->privatecnt == 0)
+				dma_cap_clear(DMA_PRIVATE, device->cap_mask);
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -571,11 +571,15 @@ struct dma_chan dma_get_any_slave_channel(struct dma_device device)`
`571`	`571`
`572`	`572`	`chan = private_candidate(&mask, device, NULL, NULL);`
`573`	`573`	`if (chan) {`
	`574`	`+ dma_cap_set(DMA_PRIVATE, device->cap_mask);`
	`575`	`+ device->privatecnt++;`
`574`	`576`	`err = dma_chan_get(chan);`
`575`	`577`	`if (err) {`
`576`	`578`	`pr_debug("%s: failed to get %s: (%d)\n",`
`577`	`579`	`__func__, dma_chan_name(chan), err);`
`578`	`580`	`chan = NULL;`
	`581`	`+ if (--device->privatecnt == 0)`
	`582`	`+ dma_cap_clear(DMA_PRIVATE, device->cap_mask);`
`579`	`583`	`}`
`580`	`584`	`}`
`581`	`585`