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From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	dri-devel@lists.freedesktop.org, linux-mm@kvack.org,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	x86@kernel.org, Chris Wilson <chris@chris-wilson.co.uk>,
	Minchan Kim <minchan@kernel.org>,
	Matthew Auld <matthew.auld@intel.com>,
	xen-devel@lists.xenproject.org,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Nitin Gupta <ngupta@vflare.org>
Subject: [Intel-gfx] [PATCH 06/11] drm/i915: use vmap in shmem_pin_map
Date: Thu, 24 Sep 2020 15:58:48 +0200
Message-ID: <20200924135853.875294-7-hch@lst.de> (raw)
In-Reply-To: <20200924135853.875294-1-hch@lst.de>

shmem_pin_map somewhat awkwardly reimplements vmap using
alloc_vm_area and manual pte setup.  The only practical difference
is that alloc_vm_area prefeaults the vmalloc area PTEs, which doesn't
seem to be required here (and could be added to vmap using a flag if
actually required).  Switch to use vmap, and use vfree to free both the
vmalloc mapping and the page array, as well as dropping the references
to each page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/i915/gt/shmem_utils.c | 76 +++++++--------------------
 1 file changed, 18 insertions(+), 58 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c b/drivers/gpu/drm/i915/gt/shmem_utils.c
index 43c7acbdc79dea..f011ea42487e11 100644
--- a/drivers/gpu/drm/i915/gt/shmem_utils.c
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -49,80 +49,40 @@ struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
 	return file;
 }
 
-static size_t shmem_npte(struct file *file)
-{
-	return file->f_mapping->host->i_size >> PAGE_SHIFT;
-}
-
-static void __shmem_unpin_map(struct file *file, void *ptr, size_t n_pte)
-{
-	unsigned long pfn;
-
-	vunmap(ptr);
-
-	for (pfn = 0; pfn < n_pte; pfn++) {
-		struct page *page;
-
-		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
-						   GFP_KERNEL);
-		if (!WARN_ON(IS_ERR(page))) {
-			put_page(page);
-			put_page(page);
-		}
-	}
-}
-
 void *shmem_pin_map(struct file *file)
 {
-	const size_t n_pte = shmem_npte(file);
-	pte_t *stack[32], **ptes, **mem;
-	struct vm_struct *area;
-	unsigned long pfn;
-
-	mem = stack;
-	if (n_pte > ARRAY_SIZE(stack)) {
-		mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
-		if (!mem)
-			return NULL;
-	}
+	struct page **pages;
+	size_t n_pages, i;
+	void *vaddr;
 
-	area = alloc_vm_area(n_pte << PAGE_SHIFT, mem);
-	if (!area) {
-		if (mem != stack)
-			kvfree(mem);
+	n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
+	pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
+	if (!pages)
 		return NULL;
-	}
 
-	ptes = mem;
-	for (pfn = 0; pfn < n_pte; pfn++) {
-		struct page *page;
-
-		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
-						   GFP_KERNEL);
-		if (IS_ERR(page))
+	for (i = 0; i < n_pages; i++) {
+		pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
+						       GFP_KERNEL);
+		if (IS_ERR(pages[i]))
 			goto err_page;
-
-		**ptes++ = mk_pte(page,  PAGE_KERNEL);
 	}
 
-	if (mem != stack)
-		kvfree(mem);
-
+	vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
+	if (!vaddr)
+		goto err_page;
 	mapping_set_unevictable(file->f_mapping);
-	return area->addr;
-
+	return vaddr;
 err_page:
-	if (mem != stack)
-		kvfree(mem);
-
-	__shmem_unpin_map(file, area->addr, pfn);
+	while (--i >= 0)
+		put_page(pages[i]);
+	kvfree(pages);
 	return NULL;
 }
 
 void shmem_unpin_map(struct file *file, void *ptr)
 {
 	mapping_clear_unevictable(file->f_mapping);
-	__shmem_unpin_map(file, ptr, shmem_npte(file));
+	vfree(ptr);
 }
 
 static int __shmem_rw(struct file *file, loff_t off,
-- 
2.28.0

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  parent reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-24 13:58 [Intel-gfx] remove alloc_vm_area v2 Christoph Hellwig
2020-09-24 13:58 ` [Intel-gfx] [PATCH 01/11] mm: update the documentation for vfree Christoph Hellwig
2020-09-24 13:58 ` [Intel-gfx] [PATCH 02/11] mm: add a VM_MAP_PUT_PAGES flag for vmap Christoph Hellwig
2020-09-24 13:58 ` [Intel-gfx] [PATCH 03/11] mm: add a vmap_pfn function Christoph Hellwig
2020-09-24 13:58 ` [Intel-gfx] [PATCH 04/11] mm: allow a NULL fn callback in apply_to_page_range Christoph Hellwig
2020-09-24 13:58 ` [Intel-gfx] [PATCH 05/11] zsmalloc: switch from alloc_vm_area to get_vm_area Christoph Hellwig
2020-09-24 13:58 ` Christoph Hellwig [this message]
2020-09-25 13:05   ` [Intel-gfx] [PATCH 06/11] drm/i915: use vmap in shmem_pin_map Tvrtko Ursulin
2020-09-24 13:58 ` [Intel-gfx] [PATCH 07/11] drm/i915: stop using kmap in i915_gem_object_map Christoph Hellwig
2020-09-25 13:01   ` Tvrtko Ursulin
2020-09-24 13:58 ` [Intel-gfx] [PATCH 08/11] drm/i915: use vmap " Christoph Hellwig
2020-09-25 13:11   ` Tvrtko Ursulin
2020-09-25 14:08   ` Matthew Auld
2020-09-25 16:02     ` Christoph Hellwig
2020-09-25 16:09   ` [Intel-gfx] [PATCH 08/11, fixed] " Christoph Hellwig
2020-09-24 13:58 ` [Intel-gfx] [PATCH 09/11] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv Christoph Hellwig
2020-09-24 23:42   ` boris.ostrovsky
2020-09-24 13:58 ` [Intel-gfx] [PATCH 10/11] x86/xen: open code alloc_vm_area in arch_gnttab_valloc Christoph Hellwig
2020-09-24 23:43   ` boris.ostrovsky
2020-09-24 13:58 ` [Intel-gfx] [PATCH 11/11] mm: remove alloc_vm_area Christoph Hellwig
2020-09-24 15:09 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/11] mm: update the documentation for vfree Patchwork
2020-09-24 15:34 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-09-24 20:44 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2020-09-25 16:50 ` [Intel-gfx] ✓ Fi.CI.BAT: success for series starting with [01/11] mm: update the documentation for vfree (rev2) Patchwork
2020-09-26  0:08 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2020-09-26  2:43 ` [Intel-gfx] remove alloc_vm_area v2 Andrew Morton
2020-09-26  6:29   ` Christoph Hellwig
2020-09-28 10:13     ` Joonas Lahtinen
2020-09-28 12:37       ` Christoph Hellwig
2020-09-29 12:43         ` Joonas Lahtinen
2020-09-30 14:48           ` Christoph Hellwig
2020-09-30 18:37             ` Daniel Vetter
2020-10-02 12:21 [Intel-gfx] remove alloc_vm_area v4 Christoph Hellwig
2020-10-02 12:21 ` [Intel-gfx] [PATCH 06/11] drm/i915: use vmap in shmem_pin_map Christoph Hellwig

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