Looks correct (fixing the return value from the function
wdata_fill_from_iovec())
Reviewed-by: Shirish Pargaonkar <spargaonkar@xxxxxxxx>
On Mon, Jul 21, 2014 at 10:45 AM, Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
> ---
> fs/cifs/file.c | 84 ++++++++++++++++++++++++++++++++++------------------------
> 1 file changed, 50 insertions(+), 34 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index ff4a9c3..f96f61c 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2423,11 +2423,53 @@ cifs_uncached_retry_writev(struct cifs_writedata *wdata)
> return rc;
> }
>
> +static int
> +wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
> + size_t *len, unsigned long *num_pages)
> +{
> + size_t save_len, copied, bytes, cur_len = *len;
> + unsigned long i, nr_pages = *num_pages;
> +
> + save_len = cur_len;
> + for (i = 0; i < nr_pages; i++) {
> + bytes = min_t(const size_t, cur_len, PAGE_SIZE);
> + copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from);
> + cur_len -= 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;
> + *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. Return -EFAULT and let
> + * the caller free anything we allocated and bail out.
> + */
> + if (!cur_len)
> + return -EFAULT;
> +
> + /*
> + * i + 1 now represents the number of pages we actually used in
> + * the copy phase above.
> + */
> + *num_pages = i + 1;
> + return 0;
> +}
> +
> static ssize_t
> cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
> {
> - unsigned long nr_pages, i;
> - size_t bytes, copied, len, cur_len;
> + unsigned long nr_pages, num_pages, i;
> + size_t len, cur_len;
> ssize_t total_written = 0;
> loff_t offset;
> struct cifsFileInfo *open_file;
> @@ -2464,8 +2506,6 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
> pid = current->tgid;
>
> do {
> - size_t save_len;
> -
> nr_pages = get_numpages(cifs_sb->wsize, len, &cur_len);
> wdata = cifs_writedata_alloc(nr_pages,
> cifs_uncached_writev_complete);
> @@ -2480,44 +2520,20 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
> break;
> }
>
> - save_len = cur_len;
> - for (i = 0; i < nr_pages; i++) {
> - bytes = min_t(size_t, cur_len, PAGE_SIZE);
> - copied = copy_page_from_iter(wdata->pages[i], 0, bytes,
> - from);
> - cur_len -= 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) {
> + num_pages = nr_pages;
> + rc = wdata_fill_from_iovec(wdata, from, &cur_len, &num_pages);
> + if (rc) {
> 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.
> + * Bring nr_pages down to the number of pages we actually used,
> + * and free any pages that we didn't use.
> */
> - for ( ; nr_pages > i + 1; nr_pages--)
> + for ( ; nr_pages > num_pages; nr_pages--)
> put_page(wdata->pages[nr_pages - 1]);
>
> wdata->sync_mode = WB_SYNC_ALL;
> --
> 1.8.1.2
>
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