On 11/07/2020 14:38, Christophe JAILLET wrote:
Le 11/07/2020 à 14:35, Suraj Upadhyay a écrit :
The legacy API wrappers in include/linux/pci-dma-compat.h
should go away as it creates unnecessary midlayering
for include/linux/dma-mapping.h APIs, instead use dma-mapping.h
APIs directly.
The patch has been generated with the coccinelle script below
and compile-tested.
[...]
@@ expression E1, E2, E3; @@
- pci_alloc_consistent(E1, E2, E3)
+ dma_alloc_coherent(&E1->dev, E2, E3, GFP_ATOMIC)
@@ expression E1, E2, E3; @@
- pci_zalloc_consistent(E1, E2, E3)
+ dma_alloc_coherent(&E1->dev, E2, E3, GFP_ATOMIC)
This is the tricky part of this kind of cleanup, see below.
GFP_ATOMIC can't be wrong because it is was exactly what was done with
the pci_ function.
However, most of the time, it can safely be replaced by GFP_KERNEL which
gives more opportunities to the memory allocator.
[...]
diff --git a/drivers/staging/comedi/drivers/s626.c
b/drivers/staging/comedi/drivers/s626.c
index 084a8e7b9fc2..c159416662fd 100644
--- a/drivers/staging/comedi/drivers/s626.c
+++ b/drivers/staging/comedi/drivers/s626.c
@@ -2130,13 +2130,15 @@ static int s626_allocate_dma_buffers(struct
comedi_device *dev)
void *addr;
dma_addr_t appdma;
- addr = pci_alloc_consistent(pcidev, S626_DMABUF_SIZE, &appdma);
+ addr = dma_alloc_coherent(&pcidev->dev, S626_DMABUF_SIZE, &appdma,
+ GFP_ATOMIC);
if (!addr)
return -ENOMEM;
devpriv->ana_buf.logical_base = addr;
devpriv->ana_buf.physical_base = appdma;
- addr = pci_alloc_consistent(pcidev, S626_DMABUF_SIZE, &appdma);
+ addr = dma_alloc_coherent(&pcidev->dev, S626_DMABUF_SIZE, &appdma,
+ GFP_ATOMIC);
if (!addr)
return -ENOMEM;
devpriv->rps_buf.logical_base = addr;
's626_allocate_dma_buffers()' is only called from 's626_auto_attach()'.
In this function, around the call to 's626_allocate_dma_buffers()', you
can see:
- a few lines before, a call to 'comedi_alloc_devpriv()'
- a few lines after, a call to 'comedi_alloc_subdevices()'
These 2 functions make some memory allocation using GFP_KERNEL.
So it is likely that using GFP_KERNEL in your proposal is also valid.
Indeed, GFP_KERNEL is perfectly fine here. It could be done as a
follow-up patch, or done in a v2 of this patch with a mention in the
patch description.
--
-=( Ian Abbott <abbotti@xxxxxxxxx> || Web: www.mev.co.uk )=-
-=( MEV Ltd. is a company registered in England & Wales. )=-
-=( Registered number: 02862268. Registered address: )=-
-=( 15 West Park Road, Bramhall, STOCKPORT, SK7 3JZ, UK. )=-
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
