From b2de3643c5024fc4fd128ba7767c7fb8b714bea7 Mon Sep 17 00:00:00 2001
From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Date: Sat, 16 Jan 2021 22:21:46 +0100
Subject: [PATCH] media: cx25821: Fix a bug when reallocating some dma memory
Git-commit: b2de3643c5024fc4fd128ba7767c7fb8b714bea7
Patch-mainline: v5.12-rc1
References: git-fixes

This function looks like a realloc.

However, if 'risc->cpu != NULL', the memory will be freed, but never
reallocated with the bigger 'size'.
Explicitly set 'risc->cpu' to NULL, so that the reallocation is
correctly performed a few lines below.

[hverkuil: NULL != risc->cpu -> risc->cpu]

Fixes: 5ede94c70553 ("[media] cx25821: remove bogus btcx_risc dependency)
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/pci/cx25821/cx25821-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/pci/cx25821/cx25821-core.c b/drivers/media/pci/cx25821/cx25821-core.c
index 6f8ffab8840f..07b6d0c49bbf 100644
--- a/drivers/media/pci/cx25821/cx25821-core.c
+++ b/drivers/media/pci/cx25821/cx25821-core.c
@@ -976,8 +976,10 @@ int cx25821_riscmem_alloc(struct pci_dev *pci,
 	__le32 *cpu;
 	dma_addr_t dma = 0;
 
-	if (NULL != risc->cpu && risc->size < size)
+	if (risc->cpu && risc->size < size) {
 		pci_free_consistent(pci, risc->size, risc->cpu, risc->dma);
+		risc->cpu = NULL;
+	}
 	if (NULL == risc->cpu) {
 		cpu = pci_zalloc_consistent(pci, size, &dma);
 		if (NULL == cpu)
-- 
2.26.2