dmaengine: at_xdma: handle errors of at_xdmac_alloc_desc() correctly

commit 3770d92bd5237d686e49da7b2fb86f53ee6ed259 upstream.

It seems that it is valid to have less than the requested number of
descriptors. But what is not valid and leads to subsequent errors is to
have zero descriptors. In that case, abort the probing.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220526135111.1470926-1-michael@walle.cc
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 2af0e151b31b8dca1e11c23e49d4118febd94ca8..c8dd0eef0b67b8ac9cf3b3e6a5754ed7bf4a5d02 100644 (file)
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1804,6 +1804,11 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
        for (i = 0; i < init_nr_desc_per_channel; i++) {
                desc = at_xdmac_alloc_desc(chan, GFP_ATOMIC);
                if (!desc) {
+                       if (i == 0) {
+                               dev_warn(chan2dev(chan),
+                                        "can't allocate any descriptors\n");
+                               return -EIO;
+                       }
                        dev_warn(chan2dev(chan),
                                "only %d descriptors have been allocated\n", i);
                        break;