ACPI, APEI, Fix error path for memory allocation

In ERST debug/test support patch, a dynamic allocated buffer is
used. The may-failed memory allocation should be tried firstly before
free the previous buffer.

APEI resource management memory allocation related error path is fixed
too.

v2:

- Fix error messages for APEI resources management

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 26 insertions, 11 deletions

diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
index 73fd0c7487c1..4a904a4bf05f 100644
--- a/drivers/acpi/apei/apei-base.c
+++ b/drivers/acpi/apei/apei-base.c
@@ -445,11 +445,15 @@ EXPORT_SYMBOL_GPL(apei_resources_sub);
 int apei_resources_request(struct apei_resources *resources,
                            const char *desc)
 {
-        struct apei_res *res, *res_bak;
+        struct apei_res *res, *res_bak = NULL;
         struct resource *r;
+        int rc;
 
-        apei_resources_sub(resources, &apei_resources_all);
+        rc = apei_resources_sub(resources, &apei_resources_all);
+        if (rc)
+                return rc;
 
+        rc = -EINVAL;
         list_for_each_entry(res, &resources->iomem, list) {
                 r = request_mem_region(res->start, res->end - res->start,
                                        desc);
@@ -475,7 +479,11 @@ int apei_resources_request(struct apei_resources *resources,
                 }
         }
 
-        apei_resources_merge(&apei_resources_all, resources);
+        rc = apei_resources_merge(&apei_resources_all, resources);
+        if (rc) {
+                pr_err(APEI_PFX "Fail to merge resources!\n");
+                goto err_unmap_ioport;
+        }
 
         return 0;
 err_unmap_ioport:
@@ -491,12 +499,13 @@ err_unmap_iomem:
                         break;
                 release_mem_region(res->start, res->end - res->start);
         }
-        return -EINVAL;
+        return rc;
 }
 EXPORT_SYMBOL_GPL(apei_resources_request);
 
 void apei_resources_release(struct apei_resources *resources)
 {
+        int rc;
         struct apei_res *res;
 
         list_for_each_entry(res, &resources->iomem, list)
@@ -504,7 +513,9 @@ void apei_resources_release(struct apei_resources *resources)
         list_for_each_entry(res, &resources->ioport, list)
                 release_region(res->start, res->end - res->start);
 
-        apei_resources_sub(&apei_resources_all, resources);
+        rc = apei_resources_sub(&apei_resources_all, resources);
+        if (rc)
+                pr_err(APEI_PFX "Fail to sub resources!\n");
 }
 EXPORT_SYMBOL_GPL(apei_resources_release);
 
diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c
index 5281ddda2777..8561cfefa3dc 100644
--- a/drivers/acpi/apei/erst-dbg.c
+++ b/drivers/acpi/apei/erst-dbg.c
@@ -111,11 +111,13 @@ retry:
                 goto out;
         }
         if (len > erst_dbg_buf_len) {
-                kfree(erst_dbg_buf);
+                void *p;
                 rc = -ENOMEM;
-                erst_dbg_buf = kmalloc(len, GFP_KERNEL);
-                if (!erst_dbg_buf)
+                p = kmalloc(len, GFP_KERNEL);
+                if (!p)
                         goto out;
+                kfree(erst_dbg_buf);
+                erst_dbg_buf = p;
                 erst_dbg_buf_len = len;
                 goto retry;
         }
@@ -150,11 +152,13 @@ static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf,
         if (mutex_lock_interruptible(&erst_dbg_mutex))
                 return -EINTR;
         if (usize > erst_dbg_buf_len) {
-                kfree(erst_dbg_buf);
+                void *p;
                 rc = -ENOMEM;
-                erst_dbg_buf = kmalloc(usize, GFP_KERNEL);
-                if (!erst_dbg_buf)
+                p = kmalloc(usize, GFP_KERNEL);
+                if (!p)
                         goto out;
+                kfree(erst_dbg_buf);
+                erst_dbg_buf = p;
                 erst_dbg_buf_len = usize;
         }
         rc = copy_from_user(erst_dbg_buf, ubuf, usize);