[PATCH v3] iommu/io-pgtable-arm-v7s: Add error handle for page table allocation failure

[<yf.wang@mediatek.com>]

From: Yunfei Wang <yf.wang@mediatek.com>

In __arm_v7s_alloc_table function:
iommu call kmem_cache_alloc to allocate page table, this function
allocate memory may fail, when kmem_cache_alloc fails to allocate
table, call virt_to_phys will be abnomal and return unexpected phys
and goto out_free, then call kmem_cache_free to release table will
trigger KE, __get_free_pages and free_pages have similar problem,
so add error handle for page table allocation failure.

Fixes: 29859aeb8a6ea ("iommu/io-pgtable-arm-v7s: Abort allocation when table address overflows the PTE")
Signed-off-by: Yunfei Wang <yf.wang@mediatek.com>
Cc: <stable@vger.kernel.org> # 5.10.*
---
v3: Update patch
    1. Remove unnecessary log print as suggested by Will.
    2. Remove unnecessary condition check.
v2: Cc stable@vger.kernel.org
    1. This patch needs to be merged stable branch, add stable@vger.kernel.org
       in mail list.
    2. There is No new code change in v2.

---
 drivers/iommu/io-pgtable-arm-v7s.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index bfb6acb651e5..be066c1503d3 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -246,13 +246,17 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp,
 			__GFP_ZERO | ARM_V7S_TABLE_GFP_DMA, get_order(size));
 	else if (lvl == 2)
 		table = kmem_cache_zalloc(data->l2_tables, gfp);
+
+	if (!table)
+		return NULL;
+
 	phys = virt_to_phys(table);
 	if (phys != (arm_v7s_iopte)phys) {
 		/* Doesn't fit in PTE */
 		dev_err(dev, "Page table does not fit in PTE: %pa", &phys);
 		goto out_free;
 	}
-	if (table && !cfg->coherent_walk) {
+	if (!cfg->coherent_walk) {
 		dma = dma_map_single(dev, table, size, DMA_TO_DEVICE);
 		if (dma_mapping_error(dev, dma))
 			goto out_free;
-- 
2.18.0