[Intel-gfx] [PATCH 3/9] [v3] drm/i915/bdw: Split ppgtt initialization up
Ben Widawsky
ben at bwidawsk.net
Wed Feb 19 23:40:02 CET 2014
On Wed, Feb 19, 2014 at 11:50:51PM +0200, Imre Deak wrote:
> On Wed, 2014-02-19 at 12:09 -0800, Ben Widawsky wrote:
> > Like cleanup in an earlier patch, the code becomes much more readable,
> > and easier to extend if we extract out helper functions for the various
> > stages of init.
> >
> > Note that with this patch it becomes really simple, and tempting to begin
> > using the 'goto out' idiom with explicit free/fini semantics. I've
> > kept the error path as similar as possible to the cleanup() function to
> > make sure cleanup is as robust as possible
> >
> > v2: Remove comment "NB:From here on, ppgtt->base.cleanup() should
> > function properly"
> > Update commit message to reflect above
> >
> > v3: Rebased on top of bugfixes found in the previous patch by Imre
> > Moved number of pd pages assertion to the proper place (Imre)
> >
> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> > ---
> > drivers/gpu/drm/i915/i915_gem_gtt.c | 172 ++++++++++++++++++++++++++----------
> > 1 file changed, 124 insertions(+), 48 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 03f586aa..03ef760 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -366,6 +366,118 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
> > gen8_ppgtt_free(ppgtt);
> > }
> >
> > +static int gen8_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt,
> > + const int max_pdp)
> > +{
> > + struct page *pt_pages;
> > + const int num_pt_pages = GEN8_PDES_PER_PAGE * max_pdp;
> > +
> > + pt_pages = alloc_pages(GFP_KERNEL, get_order(num_pt_pages << PAGE_SHIFT));
> > + if (!pt_pages)
> > + return -ENOMEM;
> > +
> > + ppgtt->gen8_pt_pages = pt_pages;
> > + ppgtt->num_pt_pages = 1 << get_order(num_pt_pages << PAGE_SHIFT);
> > +
> > + return 0;
> > +}
> > +
> > +static int gen8_ppgtt_allocate_dma(struct i915_hw_ppgtt *ppgtt)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < ppgtt->num_pd_entries; i++) {
> > + ppgtt->gen8_pt_dma_addr[i] = kcalloc(GEN8_PDES_PER_PAGE,
> > + sizeof(dma_addr_t),
> > + GFP_KERNEL);
> > + if (!ppgtt->gen8_pt_dma_addr[i]) {
> > + kfree(ppgtt->gen8_pt_dma_addr);
> > + while(i--)
> > + kfree(ppgtt->gen8_pt_dma_addr[i]);
>
> Sorry for missing this in my review, but ppgtt->gen8_pt_dma_addr is used
> after being freed. Also after returning -ENOMEM, we'll call
> gen8_ppgtt_free() which will try to kfree these for a second time. I
> think doing here just if (!ppgtt->gen8_pt_dma_addr[i]) return -ENOMEM;
> would work. The kfree() in gen8_ppgtt_free() would also dtrt if
> ppgtt->gen8_pt_dma_addr[i] is NULL, b/c it wasn't yet kcalloc()'d. With
> that fixed this patch looks ok to me, so:
>
> Reviewed-by: Imre Deak <imre.deak at intel.com>
>
i < ppgtt->num_pd_entries should be 1 < num_pd_pages. Otherwise, I think
you're right.
> > +
> > + return -ENOMEM;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int gen8_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt,
> > + const int max_pdp)
> > +{
> > + ppgtt->pd_pages = alloc_pages(GFP_KERNEL, get_order(max_pdp << PAGE_SHIFT));
> > + if (!ppgtt->pd_pages)
> > + return -ENOMEM;
> > +
> > + ppgtt->num_pd_pages = 1 << get_order(max_pdp << PAGE_SHIFT);
> > + BUG_ON(ppgtt->num_pd_pages > GEN8_LEGACY_PDPS);
> > +
> > + return 0;
> > +}
> > +
> > +static int gen8_ppgtt_alloc(struct i915_hw_ppgtt *ppgtt,
> > + const int max_pdp)
> > +{
> > + int ret;
> > +
> > + ret = gen8_ppgtt_allocate_page_directories(ppgtt, max_pdp);
> > + if (ret)
> > + return ret;
> > +
> > + ret = gen8_ppgtt_allocate_page_tables(ppgtt, max_pdp);
> > + if (ret) {
> > + __free_pages(ppgtt->pd_pages, get_order(max_pdp << PAGE_SHIFT));
> > + return ret;
> > + }
> > +
> > + ppgtt->num_pd_entries = max_pdp * GEN8_PDES_PER_PAGE;
> > +
> > + ret = gen8_ppgtt_allocate_dma(ppgtt);
> > + if (ret)
> > + gen8_ppgtt_free(ppgtt);
> > +
> > + return ret;
> > +}
> > +
> > +static int gen8_ppgtt_setup_page_directories(struct i915_hw_ppgtt *ppgtt,
> > + const int pd)
> > +{
> > + dma_addr_t pd_addr;
> > + int ret;
> > +
> > + pd_addr = pci_map_page(ppgtt->base.dev->pdev,
> > + &ppgtt->pd_pages[pd], 0,
> > + PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
> > +
> > + ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pd_addr);
> > + if (ret)
> > + return ret;
> > +
> > + ppgtt->pd_dma_addr[pd] = pd_addr;
> > +
> > + return 0;
> > +}
> > +
> > +static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
> > + const int pd,
> > + const int pt)
> > +{
> > + dma_addr_t pt_addr;
> > + struct page *p;
> > + int ret;
> > +
> > + p = &ppgtt->gen8_pt_pages[pd * GEN8_PDES_PER_PAGE + pt];
> > + pt_addr = pci_map_page(ppgtt->base.dev->pdev,
> > + p, 0, PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
> > + ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pt_addr);
> > + if (ret)
> > + return ret;
> > +
> > + ppgtt->gen8_pt_dma_addr[pd][pt] = pt_addr;
> > +
> > + return 0;
> > +}
> > +
> > /**
> > * GEN8 legacy ppgtt programming is accomplished through a max 4 PDP registers
> > * with a net effect resembling a 2-level page table in normal x86 terms. Each
> > @@ -378,73 +490,37 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
> > */
> > static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
> > {
> > - struct page *pt_pages;
> > const int max_pdp = DIV_ROUND_UP(size, 1 << 30);
> > - const int num_pt_pages = GEN8_PDES_PER_PAGE * max_pdp;
> > + const int min_pt_pages = GEN8_PDES_PER_PAGE * max_pdp;
> > struct pci_dev *hwdev = ppgtt->base.dev->pdev;
> > int i, j, ret;
> >
> > if (size % (1<<30))
> > DRM_INFO("Pages will be wasted unless GTT size (%llu) is divisible by 1GB\n", size);
> >
> > - /* 1. Do all our allocations for page directories and page tables */
> > - ppgtt->pd_pages = alloc_pages(GFP_KERNEL, get_order(max_pdp << PAGE_SHIFT));
> > - if (!ppgtt->pd_pages)
> > - return -ENOMEM;
> > -
> > - pt_pages = alloc_pages(GFP_KERNEL, get_order(num_pt_pages << PAGE_SHIFT));
> > - if (!pt_pages) {
> > - __free_pages(ppgtt->pd_pages, get_order(max_pdp << PAGE_SHIFT));
> > - return -ENOMEM;
> > - }
> > -
> > - ppgtt->gen8_pt_pages = pt_pages;
> > - ppgtt->num_pd_pages = 1 << get_order(max_pdp << PAGE_SHIFT);
> > - ppgtt->num_pt_pages = 1 << get_order(num_pt_pages << PAGE_SHIFT);
> > - ppgtt->num_pd_entries = max_pdp * GEN8_PDES_PER_PAGE;
> > - BUG_ON(ppgtt->num_pd_pages > GEN8_LEGACY_PDPS);
> > -
> > - for (i = 0; i < max_pdp; i++) {
> > - ppgtt->gen8_pt_dma_addr[i] = kcalloc(GEN8_PDES_PER_PAGE,
> > - sizeof(dma_addr_t),
> > - GFP_KERNEL);
> > - if (!ppgtt->gen8_pt_dma_addr[i]) {
> > - ret = -ENOMEM;
> > - goto bail;
> > - }
> > - }
> > + /* 1. Do all our allocations for page directories and page tables. */
> > + ret = gen8_ppgtt_alloc(ppgtt, max_pdp);
> > + if (ret)
> > + return ret;
> >
> > /*
> > - * 2. Create all the DMA mappings for the page directories and page
> > - * tables
> > + * 2. Create DMA mappings for the page directories and page tables.
> > */
> > for (i = 0; i < max_pdp; i++) {
> > - dma_addr_t pd_addr, pt_addr;
> > -
> > - /* And the page directory mappings */
> > - pd_addr = pci_map_page(hwdev, &ppgtt->pd_pages[i], 0,
> > - PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
> > - ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pd_addr);
> > + ret = gen8_ppgtt_setup_page_directories(ppgtt, i);
> > if (ret)
> > goto bail;
> >
> > - ppgtt->pd_dma_addr[i] = pd_addr;
> > -
> > - /* Get the page table mappings per page directory */
> > for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
> > - struct page *p = &pt_pages[i * GEN8_PDES_PER_PAGE + j];
> > -
> > - pt_addr = pci_map_page(hwdev, p, 0, PAGE_SIZE,
> > - PCI_DMA_BIDIRECTIONAL);
> > - ret = pci_dma_mapping_error(hwdev, pt_addr);
> > + ret = gen8_ppgtt_setup_page_tables(ppgtt, i, j);
> > if (ret) {
> > ppgtt->pd_dma_addr[i] = 0;
> > - pci_unmap_page(hwdev, pd_addr, PAGE_SIZE,
> > + pci_unmap_page(hwdev,
> > + ppgtt->pd_dma_addr[i],
> > + PAGE_SIZE,
> > PCI_DMA_BIDIRECTIONAL);
> > goto bail;
> > }
> > -
> > - ppgtt->gen8_pt_dma_addr[i][j] = pt_addr;
> > }
> > }
> >
> > @@ -483,7 +559,7 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
> > ppgtt->num_pd_pages, ppgtt->num_pd_pages - max_pdp);
> > DRM_DEBUG_DRIVER("Allocated %d pages for page tables (%lld wasted)\n",
> > ppgtt->num_pt_pages,
> > - (ppgtt->num_pt_pages - num_pt_pages) +
> > + (ppgtt->num_pt_pages - min_pt_pages) +
> > size % (1<<30));
> > return 0;
> >
>
>
--
Ben Widawsky, Intel Open Source Technology Center
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