#include "internal.h"
+struct follow_page_context {
+ struct dev_pagemap *pgmap;
+ unsigned int page_mask;
+};
+
static struct page *no_page_table(struct vm_area_struct *vma,
unsigned int flags)
{
}
static struct page *follow_page_pte(struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd, unsigned int flags)
+ unsigned long address, pmd_t *pmd, unsigned int flags,
+ struct dev_pagemap **pgmap)
{
struct mm_struct *mm = vma->vm_mm;
- struct dev_pagemap *pgmap = NULL;
struct page *page;
spinlock_t *ptl;
pte_t *ptep, pte;
* Only return device mapping pages in the FOLL_GET case since
* they are only valid while holding the pgmap reference.
*/
- pgmap = get_dev_pagemap(pte_pfn(pte), NULL);
- if (pgmap)
+ *pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap);
+ if (*pgmap)
page = pte_page(pte);
else
goto no_page;
goto retry;
}
- if (flags & FOLL_GET) {
+ if (flags & FOLL_GET)
get_page(page);
-
- /* drop the pgmap reference now that we hold the page */
- if (pgmap) {
- put_dev_pagemap(pgmap);
- pgmap = NULL;
- }
- }
if (flags & FOLL_TOUCH) {
if ((flags & FOLL_WRITE) &&
!pte_dirty(pte) && !PageDirty(page))
static struct page *follow_pmd_mask(struct vm_area_struct *vma,
unsigned long address, pud_t *pudp,
- unsigned int flags, unsigned int *page_mask)
+ unsigned int flags,
+ struct follow_page_context *ctx)
{
pmd_t *pmd, pmdval;
spinlock_t *ptl;
}
if (pmd_devmap(pmdval)) {
ptl = pmd_lock(mm, pmd);
- page = follow_devmap_pmd(vma, address, pmd, flags);
+ page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap);
spin_unlock(ptl);
if (page)
return page;
}
if (likely(!pmd_trans_huge(pmdval)))
- return follow_page_pte(vma, address, pmd, flags);
+ return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
if ((flags & FOLL_NUMA) && pmd_protnone(pmdval))
return no_page_table(vma, flags);
}
if (unlikely(!pmd_trans_huge(*pmd))) {
spin_unlock(ptl);
- return follow_page_pte(vma, address, pmd, flags);
+ return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
}
if (flags & FOLL_SPLIT) {
int ret;
}
return ret ? ERR_PTR(ret) :
- follow_page_pte(vma, address, pmd, flags);
+ follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
}
page = follow_trans_huge_pmd(vma, address, pmd, flags);
spin_unlock(ptl);
- *page_mask = HPAGE_PMD_NR - 1;
+ ctx->page_mask = HPAGE_PMD_NR - 1;
return page;
}
-
static struct page *follow_pud_mask(struct vm_area_struct *vma,
unsigned long address, p4d_t *p4dp,
- unsigned int flags, unsigned int *page_mask)
+ unsigned int flags,
+ struct follow_page_context *ctx)
{
pud_t *pud;
spinlock_t *ptl;
}
if (pud_devmap(*pud)) {
ptl = pud_lock(mm, pud);
- page = follow_devmap_pud(vma, address, pud, flags);
+ page = follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap);
spin_unlock(ptl);
if (page)
return page;
if (unlikely(pud_bad(*pud)))
return no_page_table(vma, flags);
- return follow_pmd_mask(vma, address, pud, flags, page_mask);
+ return follow_pmd_mask(vma, address, pud, flags, ctx);
}
-
static struct page *follow_p4d_mask(struct vm_area_struct *vma,
unsigned long address, pgd_t *pgdp,
- unsigned int flags, unsigned int *page_mask)
+ unsigned int flags,
+ struct follow_page_context *ctx)
{
p4d_t *p4d;
struct page *page;
return page;
return no_page_table(vma, flags);
}
- return follow_pud_mask(vma, address, p4d, flags, page_mask);
+ return follow_pud_mask(vma, address, p4d, flags, ctx);
}
/**
*/
struct page *follow_page_mask(struct vm_area_struct *vma,
unsigned long address, unsigned int flags,
- unsigned int *page_mask)
+ struct follow_page_context *ctx)
{
pgd_t *pgd;
struct page *page;
struct mm_struct *mm = vma->vm_mm;
- *page_mask = 0;
+ ctx->page_mask = 0;
/* make this handle hugepd */
page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
return no_page_table(vma, flags);
}
- return follow_p4d_mask(vma, address, pgd, flags, page_mask);
+ return follow_p4d_mask(vma, address, pgd, flags, ctx);
+}
+
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ unsigned int foll_flags)
+{
+ struct follow_page_context ctx = { NULL };
+ struct page *page;
+
+ page = follow_page_mask(vma, address, foll_flags, &ctx);
+ if (ctx.pgmap)
+ put_dev_pagemap(ctx.pgmap);
+ return page;
}
static int get_gate_page(struct mm_struct *mm, unsigned long address,
unsigned int gup_flags, struct page **pages,
struct vm_area_struct **vmas, int *nonblocking)
{
- long i = 0;
- unsigned int page_mask;
+ long ret = 0, i = 0;
struct vm_area_struct *vma = NULL;
+ struct follow_page_context ctx = { NULL };
if (!nr_pages)
return 0;
pages ? &pages[i] : NULL);
if (ret)
return i ? : ret;
- page_mask = 0;
+ ctx.page_mask = 0;
goto next_page;
}
- if (!vma || check_vma_flags(vma, gup_flags))
- return i ? : -EFAULT;
+ if (!vma || check_vma_flags(vma, gup_flags)) {
+ ret = -EFAULT;
+ goto out;
+ }
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
&start, &nr_pages, i,
* If we have a pending SIGKILL, don't keep faulting pages and
* potentially allocating memory.
*/
- if (unlikely(fatal_signal_pending(current)))
- return i ? i : -ERESTARTSYS;
+ if (unlikely(fatal_signal_pending(current))) {
+ ret = -ERESTARTSYS;
+ goto out;
+ }
cond_resched();
- page = follow_page_mask(vma, start, foll_flags, &page_mask);
+
+ page = follow_page_mask(vma, start, foll_flags, &ctx);
if (!page) {
- int ret;
ret = faultin_page(tsk, vma, start, &foll_flags,
nonblocking);
switch (ret) {
case 0:
goto retry;
+ case -EBUSY:
+ ret = 0;
+ /* FALLTHRU */
case -EFAULT:
case -ENOMEM:
case -EHWPOISON:
- return i ? i : ret;
- case -EBUSY:
- return i;
+ goto out;
case -ENOENT:
goto next_page;
}
*/
goto next_page;
} else if (IS_ERR(page)) {
- return i ? i : PTR_ERR(page);
+ ret = PTR_ERR(page);
+ goto out;
}
if (pages) {
pages[i] = page;
flush_anon_page(vma, page, start);
flush_dcache_page(page);
- page_mask = 0;
+ ctx.page_mask = 0;
}
next_page:
if (vmas) {
vmas[i] = vma;
- page_mask = 0;
+ ctx.page_mask = 0;
}
- page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
+ page_increm = 1 + (~(start >> PAGE_SHIFT) & ctx.page_mask);
if (page_increm > nr_pages)
page_increm = nr_pages;
i += page_increm;
start += page_increm * PAGE_SIZE;
nr_pages -= page_increm;
} while (nr_pages);
- return i;
+out:
+ if (ctx.pgmap)
+ put_dev_pagemap(ctx.pgmap);
+ return i ? i : ret;
}
static bool vma_permits_fault(struct vm_area_struct *vma,
int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
{
- unsigned long addr, len, end;
+ unsigned long len, end;
unsigned long flags;
int nr = 0;
start &= PAGE_MASK;
- addr = start;
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
* interrupts disabled by get_futex_key.
*
* With interrupts disabled, we block page table pages from being
- * freed from under us. See mmu_gather_tlb in asm-generic/tlb.h
- * for more details.
+ * freed from under us. See struct mmu_table_batch comments in
+ * include/asm-generic/tlb.h for more details.
*
* We do not adopt an rcu_read_lock(.) here as we also want to
* block IPIs that come from THPs splitting.
if (gup_fast_permitted(start, nr_pages, write)) {
local_irq_save(flags);
- gup_pgd_range(addr, end, write, pages, &nr);
+ gup_pgd_range(start, end, write, pages, &nr);
local_irq_restore(flags);
}
projects / linux-2.6-block.git / blobdiff