@@ -526,7 +526,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
coherent_pool=nn[KMG] [ARM,KNL]
Sets the size of memory pool for coherent, atomic dma
- allocations if Contiguous Memory Allocator (CMA) is used.
+ allocations, by default set to 256K.
code_bytes [X86] How many bytes of object code to print
in an oops report.
@@ -226,7 +226,7 @@ static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struc
* DMA region above it's default value of 2MB. It must be called before the
* memory allocator is initialised, i.e. before any core_initcall.
*/
-extern void __init init_consistent_dma_size(unsigned long size);
+static inline void init_consistent_dma_size(unsigned long size) { }
/*
* For SA-1111, IXP425, and ADI systems the dma-mapping functions are "magic"
@@ -22,6 +22,7 @@
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/iommu.h>
+#include <linux/io.h>
#include <linux/vmalloc.h>
#include <asm/memory.h>
@@ -217,115 +218,70 @@ static void __dma_free_buffer(struct page *page, size_t size)
}
#ifdef CONFIG_MMU
+#ifdef CONFIG_HUGETLB_PAGE
+#error ARM Coherent DMA allocator does not (yet) support huge TLB
+#endif
-#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - consistent_base) >> PAGE_SHIFT)
-#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - consistent_base) >> PMD_SHIFT)
-
-/*
- * These are the page tables (2MB each) covering uncached, DMA consistent allocations
- */
-static pte_t **consistent_pte;
-
-#define DEFAULT_CONSISTENT_DMA_SIZE SZ_2M
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+ pgprot_t prot, struct page **ret_page);
-static unsigned long consistent_base = CONSISTENT_END - DEFAULT_CONSISTENT_DMA_SIZE;
+static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
+ pgprot_t prot, struct page **ret_page,
+ const void *caller);
-void __init init_consistent_dma_size(unsigned long size)
+static void *
+__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
+ const void *caller)
{
- unsigned long base = CONSISTENT_END - ALIGN(size, SZ_2M);
+ struct vm_struct *area;
+ unsigned long addr;
- BUG_ON(consistent_pte); /* Check we're called before DMA region init */
- BUG_ON(base < VMALLOC_END);
+ /*
+ * DMA allocation can be mapped to user space, so lets
+ * set VM_USERMAP flags too.
+ */
+ area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
+ caller);
+ if (!area)
+ return NULL;
+ addr = (unsigned long)area->addr;
+ area->phys_addr = __pfn_to_phys(page_to_pfn(page));
- /* Grow region to accommodate specified size */
- if (base < consistent_base)
- consistent_base = base;
+ if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) {
+ vunmap((void *)addr);
+ return NULL;
+ }
+ return (void *)addr;
}
-#include "vmregion.h"
-
-static struct arm_vmregion_head consistent_head = {
- .vm_lock = __SPIN_LOCK_UNLOCKED(&consistent_head.vm_lock),
- .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
- .vm_end = CONSISTENT_END,
-};
-
-#ifdef CONFIG_HUGETLB_PAGE
-#error ARM Coherent DMA allocator does not (yet) support huge TLB
-#endif
-
-/*
- * Initialise the consistent memory allocation.
- */
-static int __init consistent_init(void)
+static void __dma_free_remap(void *cpu_addr, size_t size)
{
- int ret = 0;
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int i = 0;
- unsigned long base = consistent_base;
- unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT;
-
- if (IS_ENABLED(CONFIG_CMA) && !IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
- return 0;
-
- consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL);
- if (!consistent_pte) {
- pr_err("%s: no memory\n", __func__);
- return -ENOMEM;
+ unsigned int flags = VM_ARM_DMA_CONSISTENT | VM_USERMAP;
+ struct vm_struct *area = find_vm_area(cpu_addr);
+ if (!area || (area->flags & flags) != flags) {
+ WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+ return;
}
-
- pr_debug("DMA memory: 0x%08lx - 0x%08lx:\n", base, CONSISTENT_END);
- consistent_head.vm_start = base;
-
- do {
- pgd = pgd_offset(&init_mm, base);
-
- pud = pud_alloc(&init_mm, pgd, base);
- if (!pud) {
- pr_err("%s: no pud tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
-
- pmd = pmd_alloc(&init_mm, pud, base);
- if (!pmd) {
- pr_err("%s: no pmd tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
- WARN_ON(!pmd_none(*pmd));
-
- pte = pte_alloc_kernel(pmd, base);
- if (!pte) {
- pr_err("%s: no pte tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
-
- consistent_pte[i++] = pte;
- base += PMD_SIZE;
- } while (base < CONSISTENT_END);
-
- return ret;
+ unmap_kernel_range((unsigned long)cpu_addr, size);
+ vunmap(cpu_addr);
}
-core_initcall(consistent_init);
-
-static void *__alloc_from_contiguous(struct device *dev, size_t size,
- pgprot_t prot, struct page **ret_page);
-static struct arm_vmregion_head coherent_head = {
- .vm_lock = __SPIN_LOCK_UNLOCKED(&coherent_head.vm_lock),
- .vm_list = LIST_HEAD_INIT(coherent_head.vm_list),
+struct dma_pool {
+ size_t size;
+ spinlock_t lock;
+ unsigned long *bitmap;
+ unsigned long nr_pages;
+ void *vaddr;
+ struct page *page;
};
-static size_t coherent_pool_size = DEFAULT_CONSISTENT_DMA_SIZE / 8;
+static struct dma_pool atomic_pool = {
+ .size = SZ_256K,
+};
static int __init early_coherent_pool(char *p)
{
- coherent_pool_size = memparse(p, &p);
+ atomic_pool.size = memparse(p, &p);
return 0;
}
early_param("coherent_pool", early_coherent_pool);
@@ -333,32 +289,45 @@ early_param("coherent_pool", early_coherent_pool);
/*
* Initialise the coherent pool for atomic allocations.
*/
-static int __init coherent_init(void)
+static int __init atomic_pool_init(void)
{
+ struct dma_pool *pool = &atomic_pool;
pgprot_t prot = pgprot_dmacoherent(pgprot_kernel);
- size_t size = coherent_pool_size;
+ unsigned long nr_pages = pool->size >> PAGE_SHIFT;
+ unsigned long *bitmap;
struct page *page;
void *ptr;
+ int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long);
- if (!IS_ENABLED(CONFIG_CMA))
- return 0;
+ bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+ if (!bitmap)
+ goto no_bitmap;
- ptr = __alloc_from_contiguous(NULL, size, prot, &page);
+ if (IS_ENABLED(CONFIG_CMA))
+ ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page);
+ else
+ ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot,
+ &page, NULL);
if (ptr) {
- coherent_head.vm_start = (unsigned long) ptr;
- coherent_head.vm_end = (unsigned long) ptr + size;
- printk(KERN_INFO "DMA: preallocated %u KiB pool for atomic coherent allocations\n",
- (unsigned)size / 1024);
+ spin_lock_init(&pool->lock);
+ pool->vaddr = ptr;
+ pool->page = page;
+ pool->bitmap = bitmap;
+ pool->nr_pages = nr_pages;
+ pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n",
+ (unsigned)pool->size / 1024);
return 0;
}
- printk(KERN_ERR "DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
- (unsigned)size / 1024);
+ kfree(bitmap);
+no_bitmap:
+ pr_err("DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
+ (unsigned)pool->size / 1024);
return -ENOMEM;
}
/*
* CMA is activated by core_initcall, so we must be called after it.
*/
-postcore_initcall(coherent_init);
+postcore_initcall(atomic_pool_init);
struct dma_contig_early_reserve {
phys_addr_t base;
@@ -406,112 +375,6 @@ void __init dma_contiguous_remap(void)
}
}
-static void *
-__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
- const void *caller)
-{
- struct arm_vmregion *c;
- size_t align;
- int bit;
-
- if (!consistent_pte) {
- pr_err("%s: not initialised\n", __func__);
- dump_stack();
- return NULL;
- }
-
- /*
- * Align the virtual region allocation - maximum alignment is
- * a section size, minimum is a page size. This helps reduce
- * fragmentation of the DMA space, and also prevents allocations
- * smaller than a section from crossing a section boundary.
- */
- bit = fls(size - 1);
- if (bit > SECTION_SHIFT)
- bit = SECTION_SHIFT;
- align = 1 << bit;
-
- /*
- * Allocate a virtual address in the consistent mapping region.
- */
- c = arm_vmregion_alloc(&consistent_head, align, size,
- gfp & ~(__GFP_DMA | __GFP_HIGHMEM), caller);
- if (c) {
- pte_t *pte;
- int idx = CONSISTENT_PTE_INDEX(c->vm_start);
- u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
-
- pte = consistent_pte[idx] + off;
- c->priv = page;
-
- do {
- BUG_ON(!pte_none(*pte));
-
- set_pte_ext(pte, mk_pte(page, prot), 0);
- page++;
- pte++;
- off++;
- if (off >= PTRS_PER_PTE) {
- off = 0;
- pte = consistent_pte[++idx];
- }
- } while (size -= PAGE_SIZE);
-
- dsb();
-
- return (void *)c->vm_start;
- }
- return NULL;
-}
-
-static void __dma_free_remap(void *cpu_addr, size_t size)
-{
- struct arm_vmregion *c;
- unsigned long addr;
- pte_t *ptep;
- int idx;
- u32 off;
-
- c = arm_vmregion_find_remove(&consistent_head, (unsigned long)cpu_addr);
- if (!c) {
- pr_err("%s: trying to free invalid coherent area: %p\n",
- __func__, cpu_addr);
- dump_stack();
- return;
- }
-
- if ((c->vm_end - c->vm_start) != size) {
- pr_err("%s: freeing wrong coherent size (%ld != %d)\n",
- __func__, c->vm_end - c->vm_start, size);
- dump_stack();
- size = c->vm_end - c->vm_start;
- }
-
- idx = CONSISTENT_PTE_INDEX(c->vm_start);
- off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
- ptep = consistent_pte[idx] + off;
- addr = c->vm_start;
- do {
- pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
-
- ptep++;
- addr += PAGE_SIZE;
- off++;
- if (off >= PTRS_PER_PTE) {
- off = 0;
- ptep = consistent_pte[++idx];
- }
-
- if (pte_none(pte) || !pte_present(pte))
- pr_crit("%s: bad page in kernel page table\n",
- __func__);
- } while (size -= PAGE_SIZE);
-
- flush_tlb_kernel_range(c->vm_start, c->vm_end);
-
- arm_vmregion_free(&consistent_head, c);
-}
-
static int __dma_update_pte(pte_t *pte, pgtable_t token, unsigned long addr,
void *data)
{
@@ -552,16 +415,17 @@ static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
return ptr;
}
-static void *__alloc_from_pool(struct device *dev, size_t size,
- struct page **ret_page, const void *caller)
+static void *__alloc_from_pool(size_t size, struct page **ret_page)
{
- struct arm_vmregion *c;
+ struct dma_pool *pool = &atomic_pool;
+ unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ unsigned int pageno;
+ unsigned long flags;
+ void *ptr = NULL;
size_t align;
- if (!coherent_head.vm_start) {
- printk(KERN_ERR "%s: coherent pool not initialised!\n",
- __func__);
- dump_stack();
+ if (!pool->vaddr) {
+ WARN(1, "coherent pool not initialised!\n");
return NULL;
}
@@ -571,35 +435,41 @@ static void *__alloc_from_pool(struct device *dev, size_t size,
* size. This helps reduce fragmentation of the DMA space.
*/
align = PAGE_SIZE << get_order(size);
- c = arm_vmregion_alloc(&coherent_head, align, size, 0, caller);
- if (c) {
- void *ptr = (void *)c->vm_start;
- struct page *page = virt_to_page(ptr);
- *ret_page = page;
- return ptr;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pageno = bitmap_find_next_zero_area(pool->bitmap, pool->nr_pages,
+ 0, count, (1 << align) - 1);
+ if (pageno < pool->nr_pages) {
+ bitmap_set(pool->bitmap, pageno, count);
+ ptr = pool->vaddr + PAGE_SIZE * pageno;
+ *ret_page = pool->page + pageno;
}
- return NULL;
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ return ptr;
}
-static int __free_from_pool(void *cpu_addr, size_t size)
+static int __free_from_pool(void *start, size_t size)
{
- unsigned long start = (unsigned long)cpu_addr;
- unsigned long end = start + size;
- struct arm_vmregion *c;
+ struct dma_pool *pool = &atomic_pool;
+ unsigned long pageno, count;
+ unsigned long flags;
- if (start < coherent_head.vm_start || end > coherent_head.vm_end)
+ if (start < pool->vaddr || start > pool->vaddr + pool->size)
return 0;
- c = arm_vmregion_find_remove(&coherent_head, (unsigned long)start);
-
- if ((c->vm_end - c->vm_start) != size) {
- printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
- __func__, c->vm_end - c->vm_start, size);
- dump_stack();
- size = c->vm_end - c->vm_start;
+ if (start + size > pool->vaddr + pool->size) {
+ WARN(1, "freeing wrong coherent size from pool\n");
+ return 0;
}
- arm_vmregion_free(&coherent_head, c);
+ pageno = (start - pool->vaddr) >> PAGE_SHIFT;
+ count = size >> PAGE_SHIFT;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ bitmap_clear(pool->bitmap, pageno, count);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
return 1;
}
@@ -644,7 +514,7 @@ static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot)
#define __get_dma_pgprot(attrs, prot) __pgprot(0)
#define __alloc_remap_buffer(dev, size, gfp, prot, ret, c) NULL
-#define __alloc_from_pool(dev, size, ret_page, c) NULL
+#define __alloc_from_pool(size, ret_page) NULL
#define __alloc_from_contiguous(dev, size, prot, ret) NULL
#define __free_from_pool(cpu_addr, size) 0
#define __free_from_contiguous(dev, page, size) do { } while (0)
@@ -702,10 +572,10 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (arch_is_coherent() || nommu())
addr = __alloc_simple_buffer(dev, size, gfp, &page);
+ else if (gfp & GFP_ATOMIC)
+ addr = __alloc_from_pool(size, &page);
else if (!IS_ENABLED(CONFIG_CMA))
addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
- else if (gfp & GFP_ATOMIC)
- addr = __alloc_from_pool(dev, size, &page, caller);
else
addr = __alloc_from_contiguous(dev, size, prot, &page);
@@ -998,9 +868,6 @@ static int arm_dma_set_mask(struct device *dev, u64 dma_mask)
static int __init dma_debug_do_init(void)
{
-#ifdef CONFIG_MMU
- arm_vmregion_create_proc("dma-mappings", &consistent_head);
-#endif
dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
return 0;
}
@@ -1117,61 +984,32 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t s
* Create a CPU mapping for a specified pages
*/
static void *
-__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot)
+__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot,
+ const void *caller)
{
- struct arm_vmregion *c;
- size_t align;
- size_t count = size >> PAGE_SHIFT;
- int bit;
+ unsigned int i, nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ struct vm_struct *area;
+ unsigned long p;
- if (!consistent_pte[0]) {
- pr_err("%s: not initialised\n", __func__);
- dump_stack();
+ area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
+ caller);
+ if (!area)
return NULL;
- }
- /*
- * Align the virtual region allocation - maximum alignment is
- * a section size, minimum is a page size. This helps reduce
- * fragmentation of the DMA space, and also prevents allocations
- * smaller than a section from crossing a section boundary.
- */
- bit = fls(size - 1);
- if (bit > SECTION_SHIFT)
- bit = SECTION_SHIFT;
- align = 1 << bit;
-
- /*
- * Allocate a virtual address in the consistent mapping region.
- */
- c = arm_vmregion_alloc(&consistent_head, align, size,
- gfp & ~(__GFP_DMA | __GFP_HIGHMEM), NULL);
- if (c) {
- pte_t *pte;
- int idx = CONSISTENT_PTE_INDEX(c->vm_start);
- int i = 0;
- u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
-
- pte = consistent_pte[idx] + off;
- c->priv = pages;
-
- do {
- BUG_ON(!pte_none(*pte));
-
- set_pte_ext(pte, mk_pte(pages[i], prot), 0);
- pte++;
- off++;
- i++;
- if (off >= PTRS_PER_PTE) {
- off = 0;
- pte = consistent_pte[++idx];
- }
- } while (i < count);
-
- dsb();
+ area->pages = pages;
+ area->nr_pages = nr_pages;
+ p = (unsigned long)area->addr;
- return (void *)c->vm_start;
+ for (i = 0; i < nr_pages; i++) {
+ phys_addr_t phys = __pfn_to_phys(page_to_pfn(pages[i]));
+ if (ioremap_page_range(p, p + PAGE_SIZE, phys, prot))
+ goto err;
+ p += PAGE_SIZE;
}
+ return area->addr;
+err:
+ unmap_kernel_range((unsigned long)area->addr, size);
+ vunmap(area->addr);
return NULL;
}
@@ -1230,6 +1068,16 @@ static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t si
return 0;
}
+static struct page **__iommu_get_pages(void *cpu_addr)
+{
+ struct vm_struct *area;
+
+ area = find_vm_area(cpu_addr);
+ if (area && (area->flags & VM_ARM_DMA_CONSISTENT))
+ return area->pages;
+ return NULL;
+}
+
static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
{
@@ -1248,7 +1096,8 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
if (*handle == DMA_ERROR_CODE)
goto err_buffer;
- addr = __iommu_alloc_remap(pages, size, gfp, prot);
+ addr = __iommu_alloc_remap(pages, size, gfp, prot,
+ __builtin_return_address(0));
if (!addr)
goto err_mapping;
@@ -1265,31 +1114,25 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
struct dma_attrs *attrs)
{
- struct arm_vmregion *c;
+ unsigned long uaddr = vma->vm_start;
+ unsigned long usize = vma->vm_end - vma->vm_start;
+ struct page **pages = __iommu_get_pages(cpu_addr);
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
- c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
- if (c) {
- struct page **pages = c->priv;
-
- unsigned long uaddr = vma->vm_start;
- unsigned long usize = vma->vm_end - vma->vm_start;
- int i = 0;
-
- do {
- int ret;
+ if (!pages)
+ return -ENXIO;
- ret = vm_insert_page(vma, uaddr, pages[i++]);
- if (ret) {
- pr_err("Remapping memory, error: %d\n", ret);
- return ret;
- }
+ do {
+ int ret = vm_insert_page(vma, uaddr, *pages++);
+ if (ret) {
+ pr_err("Remapping memory failed: %d\n", ret);
+ return ret;
+ }
+ uaddr += PAGE_SIZE;
+ usize -= PAGE_SIZE;
+ } while (usize > 0);
- uaddr += PAGE_SIZE;
- usize -= PAGE_SIZE;
- } while (usize > 0);
- }
return 0;
}
@@ -1300,16 +1143,19 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs)
{
- struct arm_vmregion *c;
+ struct page **pages = __iommu_get_pages(cpu_addr);
size = PAGE_ALIGN(size);
- c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
- if (c) {
- struct page **pages = c->priv;
- __dma_free_remap(cpu_addr, size);
- __iommu_remove_mapping(dev, handle, size);
- __iommu_free_buffer(dev, pages, size);
+ if (!pages) {
+ WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+ return;
}
+
+ unmap_kernel_range((unsigned long)cpu_addr, size);
+ vunmap(cpu_addr);
+
+ __iommu_remove_mapping(dev, handle, size);
+ __iommu_free_buffer(dev, pages, size);
}
/*
@@ -59,6 +59,9 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page
#define VM_ARM_MTYPE(mt) ((mt) << 20)
#define VM_ARM_MTYPE_MASK (0x1f << 20)
+/* consistent regions used by dma_alloc_attrs() */
+#define VM_ARM_DMA_CONSISTENT 0x20000000
+
#endif
#ifdef CONFIG_ZONE_DMA
@@ -93,6 +93,7 @@ extern struct vm_struct *__get_vm_area_caller(unsigned long size,
unsigned long start, unsigned long end,
const void *caller);
extern struct vm_struct *remove_vm_area(const void *addr);
+extern struct vm_struct *find_vm_area(const void *addr);
extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
struct page ***pages);
@@ -1403,7 +1403,15 @@ struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
-1, GFP_KERNEL, caller);
}
-static struct vm_struct *find_vm_area(const void *addr)
+/**
+ * find_vm_area - find a continuous kernel virtual area
+ * @addr: base address
+ *
+ * Search for the kernel VM area starting at @addr, and return it.
+ * It is up to the caller to do all required locking to keep the returned
+ * pointer valid.
+ */
+struct vm_struct *find_vm_area(const void *addr)
{
struct vmap_area *va;