[patch] iommu/amd: fix a small leak in irq_remapping_alloc()

[Dan Carpenter]

There is a memory leak here that was detected by Smatch:

        drivers/iommu/amd_iommu.c:4261 irq_remapping_alloc()
        warn: possible memory leak of 'data'

It happens if you hit the "if (!irq_data || !cfg) {" on the first
iteration through the loop.  The original code was a bit weird.  For
example, it treated the first allocation as a special case for some
reason. Anyway I cleaned it up a bit.

Fixes: ecf87b38d902 ('iommu/amd: Enhance AMD IR driver to suppport hierarchy 
irqdomain')
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
---
Please review this carefully.  I haven't tested it.

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 35a38db..3bb69e4 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -4208,11 +4208,6 @@ static int irq_remapping_alloc(struct irq_domain 
*domain, unsigned int virq,
        if (ret < 0)
                return ret;
 
-       ret = -ENOMEM;
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               goto out_free_parent;
-
        if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC) {
                if (get_irq_table(devid, true))
                        index = info->ioapic_pin;
@@ -4223,7 +4218,6 @@ static int irq_remapping_alloc(struct irq_domain *domain, 
unsigned int virq,
        }
        if (index < 0) {
                pr_warn("Failed to allocate IRTE\n");
-               kfree(data);
                goto out_free_parent;
        }
 
@@ -4232,14 +4226,16 @@ static int irq_remapping_alloc(struct irq_domain 
*domain, unsigned int virq,
                cfg = irqd_cfg(irq_data);
                if (!irq_data || !cfg) {
                        ret = -EINVAL;
-                       goto out_free_data;
+                       goto out_unwind_loop;
                }
 
-               if (i > 0) {
-                       data = kzalloc(sizeof(*data), GFP_KERNEL);
-                       if (!data)
-                               goto out_free_data;
+
+               data = kzalloc(sizeof(*data), GFP_KERNEL);
+               if (!data) {
+                       ret = -ENOMEM;
+                       goto out_unwind_loop;
                }
+
                irq_data->hwirq = (devid << 16) + i;
                irq_data->chip_data = data;
                irq_data->chip = &amd_ir_chip;
@@ -4248,8 +4244,8 @@ static int irq_remapping_alloc(struct irq_domain *domain, 
unsigned int virq,
        }
        return 0;
 
-out_free_data:
-       for (i--; i >= 0; i--) {
+out_unwind_loop:
+       while (--i >= 0) {
                irq_data = irq_domain_get_irq_data(domain, virq + i);
                if (irq_data)
                        kfree(irq_data->chip_data);
--
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