From 70eca12d80a8b51800b4ebfbc629e0ee34166779 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 5 Feb 2014 12:44:24 -0500 Subject: process_vm_access: take get_user_pages/put_pages one level up ... and trim the fuck out of process_vm_rw_pages() argument list. Signed-off-by: Al Viro --- mm/process_vm_access.c | 97 ++++++++++++++++++++------------------------------ 1 file changed, 39 insertions(+), 58 deletions(-) (limited to 'mm/process_vm_access.c') diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 70ec3156f45a..c2a1916bacbf 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -39,69 +39,39 @@ * @bytes_copied: returns number of bytes successfully copied * Returns 0 on success, error code otherwise */ -static int process_vm_rw_pages(struct task_struct *task, - struct mm_struct *mm, - struct page **process_pages, - unsigned long pa, - unsigned long start_offset, +static int process_vm_rw_pages(struct page **pages, + unsigned offset, unsigned long len, struct iov_iter *iter, int vm_write, unsigned int nr_pages_to_copy, ssize_t *bytes_copied) { - int pages_pinned; - int pgs_copied = 0; - int j; - int ret; - ssize_t bytes_to_copy; - ssize_t rc = 0; - *bytes_copied = 0; - /* Get the pages we're interested in */ - down_read(&mm->mmap_sem); - pages_pinned = get_user_pages(task, mm, pa, - nr_pages_to_copy, - vm_write, 0, process_pages, NULL); - up_read(&mm->mmap_sem); - - if (pages_pinned != nr_pages_to_copy) { - rc = -EFAULT; - goto end; - } - /* Do the copy for each page */ - for (pgs_copied = 0; - (pgs_copied < nr_pages_to_copy) && iov_iter_count(iter); - pgs_copied++) { - struct page *page = process_pages[pgs_copied]; - bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset, len); + while (iov_iter_count(iter) && nr_pages_to_copy--) { + struct page *page = *pages++; + size_t copy = min_t(ssize_t, PAGE_SIZE - offset, len); + size_t copied; if (vm_write) { - if (bytes_to_copy > iov_iter_count(iter)) - bytes_to_copy = iov_iter_count(iter); - ret = iov_iter_copy_from_user(page, - iter, start_offset, bytes_to_copy); - iov_iter_advance(iter, ret); + if (copy > iov_iter_count(iter)) + copy = iov_iter_count(iter); + copied = iov_iter_copy_from_user(page, iter, + offset, copy); + iov_iter_advance(iter, copied); set_page_dirty_lock(page); } else { - ret = copy_page_to_iter(page, start_offset, - bytes_to_copy, iter); - } - *bytes_copied += ret; - len -= ret; - if (ret < bytes_to_copy && iov_iter_count(iter)) { - rc = -EFAULT; - break; + copied = copy_page_to_iter(page, offset, copy, iter); } - start_offset = 0; + *bytes_copied += copied; + len -= copied; + if (copied < copy && iov_iter_count(iter)) + return -EFAULT; + offset = 0; } - -end: - for (j = 0; j < pages_pinned; j++) - put_page(process_pages[j]); - return rc; + return 0; } /* Maximum number of pages kmalloc'd to hold struct page's during copy */ @@ -138,7 +108,6 @@ static int process_vm_rw_single_vec(unsigned long addr, ssize_t bytes_copied_loop; ssize_t rc = 0; unsigned long nr_pages_copied = 0; - unsigned long nr_pages_to_copy; unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES / sizeof(struct pages *); @@ -150,23 +119,35 @@ static int process_vm_rw_single_vec(unsigned long addr, nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1; while ((nr_pages_copied < nr_pages) && iov_iter_count(iter)) { + int nr_pages_to_copy; + int pages_pinned; nr_pages_to_copy = min(nr_pages - nr_pages_copied, max_pages_per_loop); - rc = process_vm_rw_pages(task, mm, process_pages, pa, + /* Get the pages we're interested in */ + down_read(&mm->mmap_sem); + pages_pinned = get_user_pages(task, mm, pa, + nr_pages_to_copy, + vm_write, 0, process_pages, NULL); + up_read(&mm->mmap_sem); + + if (pages_pinned <= 0) + return -EFAULT; + + rc = process_vm_rw_pages(process_pages, start_offset, len, iter, - vm_write, nr_pages_to_copy, + vm_write, pages_pinned, &bytes_copied_loop); start_offset = 0; *bytes_copied += bytes_copied_loop; + len -= bytes_copied_loop; + nr_pages_copied += pages_pinned; + pa += pages_pinned * PAGE_SIZE; + while (pages_pinned) + put_page(process_pages[--pages_pinned]); - if (rc < 0) { - return rc; - } else { - len -= bytes_copied_loop; - nr_pages_copied += nr_pages_to_copy; - pa += nr_pages_to_copy * PAGE_SIZE; - } + if (rc < 0) + break; } return rc; -- cgit v1.2.3-59-g8ed1b