Merge remote-tracking branch 'lsk/v3.10/topic/gator' into linux-linaro-lsk

[firefly-linux-kernel-4.4.55.git] / fs / cifs / file.c

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c2934f8701daca59e8b9f04c5f8d7869d176e396..8b0c656f2ab26d79c10648fa38129bb38fc52265 100644 (file)
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2353,7 +2353,7 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
                 unsigned long nr_segs, loff_t *poffset)
 {
        unsigned long nr_pages, i;
-       size_t copied, len, cur_len;
+       size_t bytes, copied, len, cur_len;
        ssize_t total_written = 0;
        loff_t offset;
        struct iov_iter it;
@@ -2408,14 +2408,45 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
 
                save_len = cur_len;
                for (i = 0; i < nr_pages; i++) {
-                       copied = min_t(const size_t, cur_len, PAGE_SIZE);
+                       bytes = min_t(const size_t, cur_len, PAGE_SIZE);
                        copied = iov_iter_copy_from_user(wdata->pages[i], &it,
-                                                        0, copied);
+                                                        0, bytes);
                        cur_len -= copied;
                        iov_iter_advance(&it, copied);
+                       /*
+                        * If we didn't copy as much as we expected, then that
+                        * may mean we trod into an unmapped area. Stop copying
+                        * at that point. On the next pass through the big
+                        * loop, we'll likely end up getting a zero-length
+                        * write and bailing out of it.
+                        */
+                       if (copied < bytes)
+                               break;
                }
                cur_len = save_len - cur_len;
 
+               /*
+                * If we have no data to send, then that probably means that
+                * the copy above failed altogether. That's most likely because
+                * the address in the iovec was bogus. Set the rc to -EFAULT,
+                * free anything we allocated and bail out.
+                */
+               if (!cur_len) {
+                       for (i = 0; i < nr_pages; i++)
+                               put_page(wdata->pages[i]);
+                       kfree(wdata);
+                       rc = -EFAULT;
+                       break;
+               }
+
+               /*
+                * i + 1 now represents the number of pages we actually used in
+                * the copy phase above. Bring nr_pages down to that, and free
+                * any pages that we didn't use.
+                */
+               for ( ; nr_pages > i + 1; nr_pages--)
+                       put_page(wdata->pages[nr_pages - 1]);
+
                wdata->sync_mode = WB_SYNC_ALL;
                wdata->nr_pages = nr_pages;
                wdata->offset = (__u64)offset;