Re: [RFC PATCH 1/1] s390/cio: make ccw_device_dma_* more robust

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 10/11/21 16:33, Cornelia Huck wrote:
On Mon, Oct 11 2021, Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:

On 10/11/21 1:59 PM, Halil Pasic wrote:
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index 0fe7b2f2e7f5..c533d1dadc6b 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -825,13 +825,23 @@ EXPORT_SYMBOL_GPL(ccw_device_get_chid);
    */
   void *ccw_device_dma_zalloc(struct ccw_device *cdev, size_t size)
   {
-	return cio_gp_dma_zalloc(cdev->private->dma_pool, &cdev->dev, size);
+	void *addr;
+
+	if (!get_device(&cdev->dev))
+		return NULL;
+	addr = cio_gp_dma_zalloc(cdev->private->dma_pool, &cdev->dev, size);
+	if (IS_ERR_OR_NULL(addr))

I can be wrong but it seems that only dma_alloc_coherent() used in
cio_gp_dma_zalloc() report an error but the error is ignored and used as
a valid pointer.

Hm, I thought dma_alloc_coherent() returned either NULL or a valid
address?

hum, my bad, checked the wrong function, should have use my glasses or connect my brain.



So shouldn't we modify this function and just test for a NULL address here?

If I read cio_gp_dma_zalloc() correctly, we either get NULL or a valid
address, so yes.


--
Pierre Morel
IBM Lab Boeblingen



[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux