[PATCH AUTOSEL 4.4 45/47] MIPS: WARN_ON invalid DMA cache maintenance, not BUG_ON

[Sasha Levin]

From: Paul Burton <paul.burton@xxxxxxxxxx>

[ Upstream commit d4da0e97baea8768b3d66ccef3967bebd50dfc3b ]

If a driver causes DMA cache maintenance with a zero length then we
currently BUG and kill the kernel. As this is a scenario that we may
well be able to recover from, WARN & return in the condition instead.

Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Patchwork: https://patchwork.linux-mips.org/patch/14623/
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 arch/mips/mm/c-r4k.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 5d3a25e1cfae..52e8c2026853 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -712,7 +712,8 @@ static void r4k_flush_icache_range(unsigned long start, unsigned long end)
 static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size)
 {
 	/* Catch bad driver code */
-	BUG_ON(size == 0);
+	if (WARN_ON(size == 0))
+		return;
 
 	preempt_disable();
 	if (cpu_has_inclusive_pcaches) {
@@ -745,7 +746,8 @@ static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size)
 static void r4k_dma_cache_inv(unsigned long addr, unsigned long size)
 {
 	/* Catch bad driver code */
-	BUG_ON(size == 0);
+	if (WARN_ON(size == 0))
+		return;
 
 	preempt_disable();
 	if (cpu_has_inclusive_pcaches) {
-- 
2.17.1