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Subject[PATCH 075/115] ion: remove IS_ERR_OR_NULL
Date
From: Colin Cross <ccross@android.com>

IS_ERR_OR_NULL is often part of a bad pattern that can accidentally
return 0 on error:
if (IS_ERR_OR_NULL(ptr))
return PTR_ERR(ptr);

It also usually means that the errors of a function are not well
defined. Replace all uses in ion.c by ensure that the return
type of any function in ion is an ERR_PTR.

Specify that the expected return value from map_kernel or map_dma
heap ops is ERR_PTR, and warn if a heap returns NULL.

Signed-off-by: Colin Cross <ccross@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/staging/android/ion/ion.c | 28 +++++++++++++++-------------
drivers/staging/android/ion/ion_priv.h | 3 +++
2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 93b84a9..54a00fe 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -197,7 +197,9 @@ static struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
buffer->size = len;

table = heap->ops->map_dma(heap, buffer);
- if (IS_ERR_OR_NULL(table)) {
+ if (WARN_ONCE(table == NULL, "heap->ops->map_dma should return ERR_PTR on error"))
+ table = ERR_PTR(-EINVAL);
+ if (IS_ERR(table)) {
heap->ops->free(buffer);
kfree(buffer);
return ERR_PTR(PTR_ERR(table));
@@ -389,7 +391,7 @@ static struct ion_handle *ion_handle_lookup(struct ion_client *client,
if (handle->buffer == buffer)
return handle;
}
- return NULL;
+ return ERR_PTR(-EINVAL);
}

static bool ion_handle_validate(struct ion_client *client, struct ion_handle *handle)
@@ -459,7 +461,7 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
if (!((1 << heap->id) & heap_id_mask))
continue;
buffer = ion_buffer_create(heap, dev, len, align, flags);
- if (!IS_ERR_OR_NULL(buffer))
+ if (!IS_ERR(buffer))
break;
}
up_read(&dev->lock);
@@ -543,7 +545,9 @@ static void *ion_buffer_kmap_get(struct ion_buffer *buffer)
return buffer->vaddr;
}
vaddr = buffer->heap->ops->map_kernel(buffer->heap, buffer);
- if (IS_ERR_OR_NULL(vaddr))
+ if (WARN_ONCE(vaddr == NULL, "heap->ops->map_kernel should return ERR_PTR on error"))
+ return ERR_PTR(-EINVAL);
+ if (IS_ERR(vaddr))
return vaddr;
buffer->vaddr = vaddr;
buffer->kmap_cnt++;
@@ -560,7 +564,7 @@ static void *ion_handle_kmap_get(struct ion_handle *handle)
return buffer->vaddr;
}
vaddr = ion_buffer_kmap_get(buffer);
- if (IS_ERR_OR_NULL(vaddr))
+ if (IS_ERR(vaddr))
return vaddr;
handle->kmap_cnt++;
return vaddr;
@@ -954,8 +958,6 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start,
mutex_unlock(&buffer->lock);
if (IS_ERR(vaddr))
return PTR_ERR(vaddr);
- if (!vaddr)
- return -ENOMEM;
return 0;
}

@@ -1034,7 +1036,7 @@ struct ion_handle *ion_import_dma_buf(struct ion_client *client, int fd)
struct ion_handle *handle;

dmabuf = dma_buf_get(fd);
- if (IS_ERR_OR_NULL(dmabuf))
+ if (IS_ERR(dmabuf))
return ERR_PTR(PTR_ERR(dmabuf));
/* if this memory came from ion */

@@ -1049,12 +1051,12 @@ struct ion_handle *ion_import_dma_buf(struct ion_client *client, int fd)
mutex_lock(&client->lock);
/* if a handle exists for this buffer just take a reference to it */
handle = ion_handle_lookup(client, buffer);
- if (!IS_ERR_OR_NULL(handle)) {
+ if (!IS_ERR(handle)) {
ion_handle_get(handle);
goto end;
}
handle = ion_handle_create(client, buffer);
- if (IS_ERR_OR_NULL(handle))
+ if (IS_ERR(handle))
goto end;
ion_handle_add(client, handle);
end:
@@ -1070,7 +1072,7 @@ static int ion_sync_for_device(struct ion_client *client, int fd)
struct ion_buffer *buffer;

dmabuf = dma_buf_get(fd);
- if (IS_ERR_OR_NULL(dmabuf))
+ if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);

/* if this memory came from ion */
@@ -1204,7 +1206,7 @@ static int ion_open(struct inode *inode, struct file *file)

pr_debug("%s: %d\n", __func__, __LINE__);
client = ion_client_create(dev, "user");
- if (IS_ERR_OR_NULL(client))
+ if (IS_ERR(client))
return PTR_ERR(client);
file->private_data = client;

@@ -1400,7 +1402,7 @@ struct ion_device *ion_device_create(long (*custom_ioctl)
}

idev->debug_root = debugfs_create_dir("ion", NULL);
- if (IS_ERR_OR_NULL(idev->debug_root))
+ if (!idev->debug_root)
pr_err("ion: failed to create debug files.\n");

idev->custom_ioctl = custom_ioctl;
diff --git a/drivers/staging/android/ion/ion_priv.h b/drivers/staging/android/ion/ion_priv.h
index 965471a..f263563 100644
--- a/drivers/staging/android/ion/ion_priv.h
+++ b/drivers/staging/android/ion/ion_priv.h
@@ -94,6 +94,9 @@ void ion_buffer_destroy(struct ion_buffer *buffer);
* @map_kernel map memory to the kernel
* @unmap_kernel unmap memory to the kernel
* @map_user map memory to userspace
+ *
+ * allocate, phys, and map_user return 0 on success, -errno on error.
+ * map_dma and map_kernel return pointer on success, ERR_PTR on error.
*/
struct ion_heap_ops {
int (*allocate) (struct ion_heap *heap,
--
1.8.3.2


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