Messages in this thread | | | Date | Tue, 12 Oct 2021 16:10:46 +0200 | Subject | Re: [RFC PATCH 1/1] s390/cio: make ccw_device_dma_* more robust | From | Pierre Morel <> |
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On 10/11/21 16:33, Cornelia Huck wrote: > On Mon, Oct 11 2021, Pierre Morel <pmorel@linux.ibm.com> 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
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