return page;
}
+static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
+{
+ return (vma->vm_flags & VM_GROWSDOWN) &&
+ (vma->vm_start == addr) &&
+ !vma_stack_continue(vma->vm_prev, addr);
+}
+
/**
* __get_user_pages() - pin user pages in memory
* @tsk: task_struct of target task
vma = find_extend_vma(mm, start);
if (!vma && in_gate_area(mm, start)) {
unsigned long pg = start & PAGE_MASK;
- struct vm_area_struct *gate_vma = get_gate_vma(mm);
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_unmap(pte);
return i ? : -EFAULT;
}
+ vma = get_gate_vma(mm);
if (pages) {
struct page *page;
- page = vm_normal_page(gate_vma, start, *pte);
+ page = vm_normal_page(vma, start, *pte);
if (!page) {
if (!(gup_flags & FOLL_DUMP) &&
is_zero_pfn(pte_pfn(*pte)))
get_page(page);
}
pte_unmap(pte);
- if (vmas)
- vmas[i] = gate_vma;
- i++;
- start += PAGE_SIZE;
- nr_pages--;
- continue;
+ goto next_page;
}
if (!vma ||
continue;
}
+ /*
+ * If we don't actually want the page itself,
+ * and it's the stack guard page, just skip it.
+ */
+ if (!pages && stack_guard_page(vma, start))
+ goto next_page;
+
do {
struct page *page;
unsigned int foll_flags = gup_flags;
fault_flags |= FAULT_FLAG_WRITE;
if (nonblocking)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
+ if (foll_flags & FOLL_NOWAIT)
+ fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT);
ret = handle_mm_fault(mm, vma, start,
fault_flags);
}
if (ret & VM_FAULT_RETRY) {
- *nonblocking = 0;
+ if (nonblocking)
+ *nonblocking = 0;
return i;
}
flush_anon_page(vma, page, start);
flush_dcache_page(page);
}
+next_page:
if (vmas)
vmas[i] = vma;
i++;
swp_entry_t entry;
pte_t pte;
int locked;
- struct mem_cgroup *ptr = NULL;
+ struct mem_cgroup *ptr;
int exclusive = 0;
int ret = 0;
#endif
/*
- * Access another process' address space.
- * Source/target buffer must be kernel space,
- * Do not walk the page table directly, use get_user_pages
+ * Access another process' address space as given in mm. If non-NULL, use the
+ * given task for page fault accounting.
*/
-int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long addr, void *buf, int len, int write)
{
- struct mm_struct *mm;
struct vm_area_struct *vma;
void *old_buf = buf;
- mm = get_task_mm(tsk);
- if (!mm)
- return 0;
-
down_read(&mm->mmap_sem);
/* ignore errors, just check how much was successfully transferred */
while (len) {
addr += bytes;
}
up_read(&mm->mmap_sem);
- mmput(mm);
return buf - old_buf;
}
+/**
+ * access_remote_vm - access another process' address space
+ * @mm: the mm_struct of the target address space
+ * @addr: start address to access
+ * @buf: source or destination buffer
+ * @len: number of bytes to transfer
+ * @write: whether the access is a write
+ *
+ * The caller must hold a reference on @mm.
+ */
+int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+ void *buf, int len, int write)
+{
+ return __access_remote_vm(NULL, mm, addr, buf, len, write);
+}
+
+/*
+ * Access another process' address space.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr,
+ void *buf, int len, int write)
+{
+ struct mm_struct *mm;
+ int ret;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
+ mmput(mm);
+
+ return ret;
+}
+
/*
* Print the name of a VMA.
*/