On 21.05.2019 11:16, Greg KH wrote: > On Thu, May 16, 2019 at 02:47:19PM +0300, laurentiu.tudor@xxxxxxx wrote: >> From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> >> >> For HCs that have local memory, replace the current DMA API usage >> with a genalloc generic allocator to manage the mappings for these >> devices. >> This is in preparation for dropping the existing "coherent" dma >> mem declaration APIs. Current implementation was relying on a short >> circuit in the DMA API that in the end, was acting as an allocator >> for these type of devices. >> >> For context, see thread here: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.org%2Flkml%2F2019%2F4%2F22%2F357&data=02%7C01%7Claurentiu.tudor%40nxp.com%7Cf5242fb28d154ff9653208d6ddc4b41c%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636940234237524499&sdata=KEEUP1KH%2BaraWcVKogeYBzrauh%2FFTzGjSxjk%2BuNozjA%3D&reserved=0 >> >> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> >> --- >> drivers/usb/core/buffer.c | 15 +++++++++++---- >> drivers/usb/host/ohci-hcd.c | 23 ++++++++++++++++++----- >> include/linux/usb/hcd.h | 3 +++ >> 3 files changed, 32 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c >> index f641342cdec0..22a8f3f5679b 100644 >> --- a/drivers/usb/core/buffer.c >> +++ b/drivers/usb/core/buffer.c >> @@ -16,6 +16,7 @@ >> #include <linux/io.h> >> #include <linux/dma-mapping.h> >> #include <linux/dmapool.h> >> +#include <linux/genalloc.h> >> #include <linux/usb.h> >> #include <linux/usb/hcd.h> >> >> @@ -124,10 +125,12 @@ void *hcd_buffer_alloc( >> if (size == 0) >> return NULL; >> >> + if (hcd->driver->flags & HCD_LOCAL_MEM) >> + return gen_pool_dma_alloc(hcd->localmem_pool, size, dma); > > Does this patch now break things? hcd->localmem_pool at this point in > time is NULL, so this call will fail. There's no chance for any host > controller driver to actually set up this pool in this patch, so is > bisection broken? Unfortunately, yes. I could lump the patches together but I think Christoph suggestion is much better. > I think you fix this up in later patches, right? Correct. The last 2 patches update the driver. > And if so, why do we even need HCD_LOCAL_MEM anymore? Can't we just > test for the presence of hcd->localmem_pool in order to determine which > allocation method to use? Sure. There are a few more places that need updates but no big deal. --- Best Regards, Laurentiu
