diff options
| -rw-r--r-- | fs/proc/task_mmu.c | 72 |
1 files changed, 38 insertions, 34 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 05053d701ac..c492449f3b4 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -602,11 +602,6 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, return err; } -static struct mm_walk pagemap_walk = { - .pmd_entry = pagemap_pte_range, - .pte_hole = pagemap_pte_hole -}; - /* * /proc/pid/pagemap - an array mapping virtual pages to pfns * @@ -641,6 +636,11 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, struct pagemapread pm; int pagecount; int ret = -ESRCH; + struct mm_walk pagemap_walk; + unsigned long src; + unsigned long svpfn; + unsigned long start_vaddr; + unsigned long end_vaddr; if (!task) goto out; @@ -659,11 +659,15 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, if (!mm) goto out_task; - ret = -ENOMEM; + uaddr = (unsigned long)buf & PAGE_MASK; uend = (unsigned long)(buf + count); pagecount = (PAGE_ALIGN(uend) - uaddr) / PAGE_SIZE; - pages = kmalloc(pagecount * sizeof(struct page *), GFP_KERNEL); + ret = 0; + if (pagecount == 0) + goto out_mm; + pages = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL); + ret = -ENOMEM; if (!pages) goto out_mm; @@ -684,33 +688,33 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, pm.out = (u64 *)buf; pm.end = (u64 *)(buf + count); - if (!ptrace_may_attach(task)) { - ret = -EIO; - } else { - unsigned long src = *ppos; - unsigned long svpfn = src / PM_ENTRY_BYTES; - unsigned long start_vaddr = svpfn << PAGE_SHIFT; - unsigned long end_vaddr = TASK_SIZE_OF(task); - - /* watch out for wraparound */ - if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT) - start_vaddr = end_vaddr; - - /* - * The odds are that this will stop walking way - * before end_vaddr, because the length of the - * user buffer is tracked in "pm", and the walk - * will stop when we hit the end of the buffer. - */ - ret = walk_page_range(start_vaddr, end_vaddr, - &pagemap_walk); - if (ret == PM_END_OF_BUFFER) - ret = 0; - /* don't need mmap_sem for these, but this looks cleaner */ - *ppos += (char *)pm.out - buf; - if (!ret) - ret = (char *)pm.out - buf; - } + pagemap_walk.pmd_entry = pagemap_pte_range; + pagemap_walk.pte_hole = pagemap_pte_hole; + pagemap_walk.mm = mm; + pagemap_walk.private = ± + + src = *ppos; + svpfn = src / PM_ENTRY_BYTES; + start_vaddr = svpfn << PAGE_SHIFT; + end_vaddr = TASK_SIZE_OF(task); + + /* watch out for wraparound */ + if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT) + start_vaddr = end_vaddr; + + /* + * The odds are that this will stop walking way + * before end_vaddr, because the length of the + * user buffer is tracked in "pm", and the walk + * will stop when we hit the end of the buffer. + */ + ret = walk_page_range(start_vaddr, end_vaddr, &pagemap_walk); + if (ret == PM_END_OF_BUFFER) + ret = 0; + /* don't need mmap_sem for these, but this looks cleaner */ + *ppos += (char *)pm.out - buf; + if (!ret) + ret = (char *)pm.out - buf; out_pages: for (; pagecount; pagecount--) { |