| Message ID | 20200924135853.875294-9-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [01/11] mm: update the documentation for vfree | expand |
On Thu, 24 Sep 2020 at 14:59, Christoph Hellwig <hch@lst.de> wrote: > > i915_gem_object_map implements fairly low-level vmap functionality in > a driver. Split it into two helpers, one for remapping kernel memory > which can use vmap, and one for I/O memory that uses vmap_pfn. > > The only practical difference is that alloc_vm_area prefeaults the > vmalloc area PTEs, which doesn't seem to be required here for the > kernel memory case (and could be added to vmap using a flag if actually > required). > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/gpu/drm/i915/Kconfig | 1 + > drivers/gpu/drm/i915/gem/i915_gem_pages.c | 126 ++++++++++------------ > 2 files changed, 59 insertions(+), 68 deletions(-) > > diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig > index 9afa5c4a6bf006..1e1cb245fca778 100644 > --- a/drivers/gpu/drm/i915/Kconfig > +++ b/drivers/gpu/drm/i915/Kconfig > @@ -25,6 +25,7 @@ config DRM_I915 > select CRC32 > select SND_HDA_I915 if SND_HDA_CORE > select CEC_CORE if CEC_NOTIFIER > + select VMAP_PFN > help > Choose this option if you have a system that has "Intel Graphics > Media Accelerator" or "HD Graphics" integrated graphics, > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c > index 6550c0bc824ea2..b519417667eb4b 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c > @@ -232,34 +232,21 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj) > return err; > } > > -static inline pte_t iomap_pte(resource_size_t base, > - dma_addr_t offset, > - pgprot_t prot) > -{ > - return pte_mkspecial(pfn_pte((base + offset) >> PAGE_SHIFT, prot)); > -} > - > /* The 'mapping' part of i915_gem_object_pin_map() below */ > -static void *i915_gem_object_map(struct drm_i915_gem_object *obj, > - enum i915_map_type type) > +static void *i915_gem_object_map_page(struct drm_i915_gem_object *obj, > + enum i915_map_type type) > { > - unsigned long n_pte = obj->base.size >> PAGE_SHIFT; > - struct sg_table *sgt = obj->mm.pages; > - pte_t *stack[32], **mem; > - struct vm_struct *area; > + unsigned long n_pages = obj->base.size >> PAGE_SHIFT, i; > + struct page *stack[32], **pages = stack, *page; > + struct sgt_iter iter; > pgprot_t pgprot; > + void *vaddr; > > - if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC) > - return NULL; > - > - if (GEM_WARN_ON(type == I915_MAP_WC && > - !static_cpu_has(X86_FEATURE_PAT))) > - return NULL; > - > - /* A single page can always be kmapped */ > - if (n_pte == 1 && type == I915_MAP_WB) { > - struct page *page = sg_page(sgt->sgl); > - > + switch (type) { > + default: > + MISSING_CASE(type); > + fallthrough; /* to use PAGE_KERNEL anyway */ > + case I915_MAP_WB: > /* > * On 32b, highmem using a finite set of indirect PTE (i.e. > * vmap) to provide virtual mappings of the high pages. > @@ -277,30 +264,8 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, > * So if the page is beyond the 32b boundary, make an explicit > * vmap. > */ > - if (!PageHighMem(page)) > - return page_address(page); > - } > - > - mem = stack; > - if (n_pte > ARRAY_SIZE(stack)) { > - /* Too big for stack -- allocate temporary array instead */ > - mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL); > - if (!mem) > - return NULL; > - } > - > - area = alloc_vm_area(obj->base.size, mem); > - if (!area) { > - if (mem != stack) > - kvfree(mem); > - return NULL; > - } > - > - switch (type) { > - default: > - MISSING_CASE(type); > - fallthrough; /* to use PAGE_KERNEL anyway */ > - case I915_MAP_WB: > + if (n_pages == 1 && !PageHighMem(sg_page(obj->mm.pages->sgl))) > + return page_address(sg_page(obj->mm.pages->sgl)); > pgprot = PAGE_KERNEL; > break; > case I915_MAP_WC: > @@ -308,30 +273,49 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, > break; > } > > - if (i915_gem_object_has_struct_page(obj)) { > - struct sgt_iter iter; > - struct page *page; > - pte_t **ptes = mem; > + if (n_pages > ARRAY_SIZE(stack)) { > + /* Too big for stack -- allocate temporary array instead */ > + pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL); > + if (!pages) > + return NULL; > + } > > - for_each_sgt_page(page, iter, sgt) > - **ptes++ = mk_pte(page, pgprot); > - } else { > - resource_size_t iomap; > - struct sgt_iter iter; > - pte_t **ptes = mem; > - dma_addr_t addr; > + i = 0; > + for_each_sgt_page(page, iter, obj->mm.pages) > + pages[i++] = page; > + vaddr = vmap(pages, n_pages, 0, pgprot); > + if (pages != stack) > + kvfree(pages); > + return vaddr; > +} > > - iomap = obj->mm.region->iomap.base; > - iomap -= obj->mm.region->region.start; > +static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj, > + enum i915_map_type type) > +{ > + resource_size_t iomap = obj->mm.region->iomap.base - > + obj->mm.region->region.start; > + unsigned long n_pfn = obj->base.size >> PAGE_SHIFT; > + unsigned long stack[32], *pfns = stack, i; > + struct sgt_iter iter; > + dma_addr_t addr; > + void *vaddr; > + > + if (type != I915_MAP_WC) > + return NULL; > > - for_each_sgt_daddr(addr, iter, sgt) > - **ptes++ = iomap_pte(iomap, addr, pgprot); > + if (n_pfn > ARRAY_SIZE(stack)) { > + /* Too big for stack -- allocate temporary array instead */ > + pfns = kvmalloc_array(n_pfn, sizeof(*pfns), GFP_KERNEL); > + if (!pfns) > + return NULL; > } > > - if (mem != stack) > - kvfree(mem); > - > - return area->addr; > + for_each_sgt_daddr(addr, iter, obj->mm.pages) > + pfns[i++] = (iomap + addr) >> PAGE_SHIFT; Missing the i = 0 fix from Dan? > + vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL_IO)); > + if (pfns != stack) > + kvfree(pfns); > + return vaddr; > } > > /* get, pin, and map the pages of the object into kernel space */ > @@ -383,7 +367,13 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj, > } > > if (!ptr) { > - ptr = i915_gem_object_map(obj, type); > + if (GEM_WARN_ON(type == I915_MAP_WC && > + !static_cpu_has(X86_FEATURE_PAT))) > + ptr = NULL; > + else if (i915_gem_object_has_struct_page(obj)) > + ptr = i915_gem_object_map_page(obj, type); > + else > + ptr = i915_gem_object_map_pfn(obj, type); > if (!ptr) { > err = -ENOMEM; > goto err_unpin; > -- > 2.28.0 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
On Fri, Sep 25, 2020 at 03:08:59PM +0100, Matthew Auld wrote: > > + i = 0; > > + for_each_sgt_page(page, iter, obj->mm.pages) > > + pages[i++] = page; > > + vaddr = vmap(pages, n_pages, 0, pgprot); > > + if (pages != stack) > > + kvfree(pages); > > + return vaddr; > > +} > > - return area->addr; > > + for_each_sgt_daddr(addr, iter, obj->mm.pages) > > + pfns[i++] = (iomap + addr) >> PAGE_SHIFT; > > Missing the i = 0 fix from Dan? Yeah, looks like I only managed to apply the one in the page based version above.
diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig index 9afa5c4a6bf006..1e1cb245fca778 100644 --- a/drivers/gpu/drm/i915/Kconfig +++ b/drivers/gpu/drm/i915/Kconfig @@ -25,6 +25,7 @@ config DRM_I915 select CRC32 select SND_HDA_I915 if SND_HDA_CORE select CEC_CORE if CEC_NOTIFIER + select VMAP_PFN help Choose this option if you have a system that has "Intel Graphics Media Accelerator" or "HD Graphics" integrated graphics, diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c index 6550c0bc824ea2..b519417667eb4b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c @@ -232,34 +232,21 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj) return err; } -static inline pte_t iomap_pte(resource_size_t base, - dma_addr_t offset, - pgprot_t prot) -{ - return pte_mkspecial(pfn_pte((base + offset) >> PAGE_SHIFT, prot)); -} - /* The 'mapping' part of i915_gem_object_pin_map() below */ -static void *i915_gem_object_map(struct drm_i915_gem_object *obj, - enum i915_map_type type) +static void *i915_gem_object_map_page(struct drm_i915_gem_object *obj, + enum i915_map_type type) { - unsigned long n_pte = obj->base.size >> PAGE_SHIFT; - struct sg_table *sgt = obj->mm.pages; - pte_t *stack[32], **mem; - struct vm_struct *area; + unsigned long n_pages = obj->base.size >> PAGE_SHIFT, i; + struct page *stack[32], **pages = stack, *page; + struct sgt_iter iter; pgprot_t pgprot; + void *vaddr; - if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC) - return NULL; - - if (GEM_WARN_ON(type == I915_MAP_WC && - !static_cpu_has(X86_FEATURE_PAT))) - return NULL; - - /* A single page can always be kmapped */ - if (n_pte == 1 && type == I915_MAP_WB) { - struct page *page = sg_page(sgt->sgl); - + switch (type) { + default: + MISSING_CASE(type); + fallthrough; /* to use PAGE_KERNEL anyway */ + case I915_MAP_WB: /* * On 32b, highmem using a finite set of indirect PTE (i.e. * vmap) to provide virtual mappings of the high pages. @@ -277,30 +264,8 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, * So if the page is beyond the 32b boundary, make an explicit * vmap. */ - if (!PageHighMem(page)) - return page_address(page); - } - - mem = stack; - if (n_pte > ARRAY_SIZE(stack)) { - /* Too big for stack -- allocate temporary array instead */ - mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL); - if (!mem) - return NULL; - } - - area = alloc_vm_area(obj->base.size, mem); - if (!area) { - if (mem != stack) - kvfree(mem); - return NULL; - } - - switch (type) { - default: - MISSING_CASE(type); - fallthrough; /* to use PAGE_KERNEL anyway */ - case I915_MAP_WB: + if (n_pages == 1 && !PageHighMem(sg_page(obj->mm.pages->sgl))) + return page_address(sg_page(obj->mm.pages->sgl)); pgprot = PAGE_KERNEL; break; case I915_MAP_WC: @@ -308,30 +273,49 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, break; } - if (i915_gem_object_has_struct_page(obj)) { - struct sgt_iter iter; - struct page *page; - pte_t **ptes = mem; + if (n_pages > ARRAY_SIZE(stack)) { + /* Too big for stack -- allocate temporary array instead */ + pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL); + if (!pages) + return NULL; + } - for_each_sgt_page(page, iter, sgt) - **ptes++ = mk_pte(page, pgprot); - } else { - resource_size_t iomap; - struct sgt_iter iter; - pte_t **ptes = mem; - dma_addr_t addr; + i = 0; + for_each_sgt_page(page, iter, obj->mm.pages) + pages[i++] = page; + vaddr = vmap(pages, n_pages, 0, pgprot); + if (pages != stack) + kvfree(pages); + return vaddr; +} - iomap = obj->mm.region->iomap.base; - iomap -= obj->mm.region->region.start; +static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj, + enum i915_map_type type) +{ + resource_size_t iomap = obj->mm.region->iomap.base - + obj->mm.region->region.start; + unsigned long n_pfn = obj->base.size >> PAGE_SHIFT; + unsigned long stack[32], *pfns = stack, i; + struct sgt_iter iter; + dma_addr_t addr; + void *vaddr; + + if (type != I915_MAP_WC) + return NULL; - for_each_sgt_daddr(addr, iter, sgt) - **ptes++ = iomap_pte(iomap, addr, pgprot); + if (n_pfn > ARRAY_SIZE(stack)) { + /* Too big for stack -- allocate temporary array instead */ + pfns = kvmalloc_array(n_pfn, sizeof(*pfns), GFP_KERNEL); + if (!pfns) + return NULL; } - if (mem != stack) - kvfree(mem); - - return area->addr; + for_each_sgt_daddr(addr, iter, obj->mm.pages) + pfns[i++] = (iomap + addr) >> PAGE_SHIFT; + vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL_IO)); + if (pfns != stack) + kvfree(pfns); + return vaddr; } /* get, pin, and map the pages of the object into kernel space */ @@ -383,7 +367,13 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj, } if (!ptr) { - ptr = i915_gem_object_map(obj, type); + if (GEM_WARN_ON(type == I915_MAP_WC && + !static_cpu_has(X86_FEATURE_PAT))) + ptr = NULL; + else if (i915_gem_object_has_struct_page(obj)) + ptr = i915_gem_object_map_page(obj, type); + else + ptr = i915_gem_object_map_pfn(obj, type); if (!ptr) { err = -ENOMEM; goto err_unpin;
i915_gem_object_map implements fairly low-level vmap functionality in a driver. Split it into two helpers, one for remapping kernel memory which can use vmap, and one for I/O memory that uses vmap_pfn. The only practical difference is that alloc_vm_area prefeaults the vmalloc area PTEs, which doesn't seem to be required here for the kernel memory case (and could be added to vmap using a flag if actually required). Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/gpu/drm/i915/Kconfig | 1 + drivers/gpu/drm/i915/gem/i915_gem_pages.c | 126 ++++++++++------------ 2 files changed, 59 insertions(+), 68 deletions(-)