From 3770d92bd5237d686e49da7b2fb86f53ee6ed259 Mon Sep 17 00:00:00 2001
From: Michael Walle <michael@walle.cc>
Date: Thu, 26 May 2022 15:51:11 +0200
Subject: [PATCH] dmaengine: at_xdma: handle errors of at_xdmac_alloc_desc() correctly
Git-commit: 3770d92bd5237d686e49da7b2fb86f53ee6ed259
Patch-mainline: v5.19-rc6
References: git-fixes

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/dma/at_xdmac.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1846,6 +1846,11 @@ static int at_xdmac_alloc_chan_resources
 	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;