On 3/19/19 7:08 AM, Brian Starkey wrote: > Hi John, > > On Tue, Mar 05, 2019 at 12:54:29PM -0800, John Stultz wrote: >> From: "Andrew F. Davis" <a...@ti.com> > > [snip] > >> + >> +#define NUM_HEAP_MINORS 128 >> +static DEFINE_IDR(dma_heap_idr); >> +static DEFINE_MUTEX(minor_lock); /* Protect idr accesses */ > > I saw that Matthew Wilcox is trying to nuke idr: > https://patchwork.freedesktop.org/series/57073/ > > Perhaps a different data structure could be considered? (I don't have > an informed opinion on which). >
Looks like XArray is the suggested replacement. Should be easy enough, the minor number would just index to our heap struct directly, I'll give it a shot and see. >> + >> +dev_t dma_heap_devt; >> +struct class *dma_heap_class; >> +struct list_head dma_heap_list; >> +struct dentry *dma_heap_debug_root; >> + >> +static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, >> + unsigned int flags) >> +{ >> + len = PAGE_ALIGN(len); >> + if (!len) >> + return -EINVAL; > > I think aligning len to pages only makes sense if heaps are going to > allocate aligned to pages too. Perhaps that's an implicit assumption? > If so, lets document it. > > Why not let the heaps take care of aligning len however they want > though? > This is how I originally had it, but I think we couldn't find any case where you would want an the start or end of a buffer to not fall on a page boundary here. It would only lead to problems. As you say though, nothing keeping us from moving that into the heaps themselves. > ... > >> + >> +int dma_heap_add(struct dma_heap *heap) >> +{ >> + struct device *dev_ret; >> + int ret; >> + >> + if (!heap->name || !strcmp(heap->name, "")) { >> + pr_err("dma_heap: Cannot add heap without a name\n"); >> + return -EINVAL; >> + } >> + >> + if (!heap->ops || !heap->ops->allocate) { >> + pr_err("dma_heap: Cannot add heap with invalid ops struct\n"); >> + return -EINVAL; >> + } >> + >> + /* Find unused minor number */ >> + mutex_lock(&minor_lock); >> + ret = idr_alloc(&dma_heap_idr, heap, 0, NUM_HEAP_MINORS, GFP_KERNEL); >> + mutex_unlock(&minor_lock); >> + if (ret < 0) { >> + pr_err("dma_heap: Unable to get minor number for heap\n"); >> + return ret; >> + } >> + heap->minor = ret; >> + >> + /* Create device */ >> + heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor); >> + dev_ret = device_create(dma_heap_class, >> + NULL, >> + heap->heap_devt, >> + NULL, >> + heap->name); >> + if (IS_ERR(dev_ret)) { >> + pr_err("dma_heap: Unable to create char device\n"); >> + return PTR_ERR(dev_ret); >> + } >> + >> + /* Add device */ >> + cdev_init(&heap->heap_cdev, &dma_heap_fops); >> + ret = cdev_add(&heap->heap_cdev, dma_heap_devt, NUM_HEAP_MINORS); > > Shouldn't this be s/dma_heap_devt/heap->heap_devt/ and a count of 1? > Hmm, strange this ever worked before.. > Also would it be better to have cdev_add/device_create the other way > around? First create the char device, then once it's all set up > register it with sysfs. > Yes that does seem to be more common, lets flip it. >> + if (ret < 0) { >> + device_destroy(dma_heap_class, heap->heap_devt); >> + pr_err("dma_heap: Unable to add char device\n"); >> + return ret; >> + } >> + >> + return 0; >> +} >> +EXPORT_SYMBOL(dma_heap_add); > > Until we've figured out how modules are going to work, I still think > it would be a good idea to not export this. > Agree. Andrew > Cheers, > -Brian > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel