Messages in this thread Patch in this message | | | Date | Mon, 5 Feb 2024 14:08:00 +0200 | From | Andy Shevchenko <> | Subject | Re: [PATCH v2] dma-coherent: add support for multi coherent rmems per dev |
| |
On Mon, Feb 05, 2024 at 07:23:00AM +0000, Howard Yen wrote: > Add support for multiple coherent rmems per device. This patch replaces > original dma_mem with dma_mems list in device structure to store multiple > rmems. > > These multiple rmems can be assigned to the device one by one by > of_reserved_mem_device_init_by_idx() with the memory-region > declaration in device tree as below and store the rmem to the dma_mems > list. > > device1@0 { > ... > memory-region = <&reserved_mem0>, <&reserved_mem1>; > ... > }; > > When driver tries to allocate memory from the rmems, looks for the first > available rmem and allocates the memory from this rmem. > > Then if driver removed, of_reserved_mem_device_release() needs to be > invoked to release all the rmems assigned to the device.
..
> --- a/kernel/dma/coherent.c > +++ b/kernel/dma/coherent.c > @@ -18,15 +18,9 @@ struct dma_coherent_mem { > unsigned long *bitmap; > spinlock_t spinlock; > bool use_dev_dma_pfn_offset; > + struct list_head node;
Have you run `pahole`? Here I see wasted bytes for nothing.
> };
..
> void dma_release_coherent_memory(struct device *dev) > { > + struct dma_coherent_mem *mem_tmp, *q; > + > if (dev) {
While at it, perhaps
if (!dev) return;
?
> - _dma_release_coherent_memory(dev->dma_mem); > - dev->dma_mem = NULL; > + list_for_each_entry_safe(mem_tmp, q, &dev->dma_mems, node) { > + list_del_init(&mem_tmp->node); > + _dma_release_coherent_memory(mem_tmp); > + } > } > }
..
> int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr) > { > - struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); > + struct dma_coherent_mem *mem_tmp; > + int ret = 0;
'ret' (1)
> - return __dma_release_from_coherent(mem, order, vaddr); > + list_for_each_entry(mem_tmp, &dev->dma_mems, node) { > + ret = __dma_release_from_coherent(mem_tmp, order, vaddr); > + if (ret == 1) > + break; > + } > + > + return ret; > }
..
> int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma, > void *vaddr, size_t size, int *ret) > { > - struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); > + struct dma_coherent_mem *mem_tmp; > + int retval = 0;
'retval' (2) Can we be consistent, please? (See (1) and (2) above.)
> + list_for_each_entry(mem_tmp, &dev->dma_mems, node) { > + retval = __dma_mmap_from_coherent(mem_tmp, vma, vaddr, size, ret); > + if (retval == 1) > + break; > + } > > - return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret); > + return retval; > }
..
> static void rmem_dma_device_release(struct reserved_mem *rmem, > struct device *dev) > { > - if (dev) > - dev->dma_mem = NULL; > + struct dma_coherent_mem *mem_tmp, *q;
> + if (dev) {
As per above, esp. taking into account that you touch this line. With proposed modification you won't need to.
> + list_for_each_entry_safe(mem_tmp, q, &dev->dma_mems, node) { > + if (mem_tmp == rmem->priv) { > + list_del_init(&mem_tmp->node); > + break; > + } > + } > + } > }
Better question, do we really need the dev check (at least in static functions) or it can be ommitted?
-- With Best Regards, Andy Shevchenko
| |