2014-07-21 7:59 GMT+04:00 Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>:
> Like put_page() for rc = 0 unused pages was moved to wdata_fill_from_iovec(),
> probably move put_page in case of -EFAULT also to wdata_fill_from_iovec()?
> So just kfree and break if(rc)?
> Also, wdata_fill_from_iovec() does not need rc, it can just return 0
> in case of no error?
Yes, or may be move the last loop from wdata_fill_from_iovec() to the caller.
>
>
> On Fri, Jun 27, 2014 at 4:57 AM, Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
>> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
>> ---
>> fs/cifs/file.c | 85 +++++++++++++++++++++++++++++++++-------------------------
>> 1 file changed, 48 insertions(+), 37 deletions(-)
>>
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index 21f9be0..e2a735a 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -2423,11 +2423,56 @@ 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 nr_pages)
>> +{
>> + int rc = 0;
>> + size_t save_len, copied, bytes, cur_len = *len;
>> + unsigned long i;
>> +
>> + 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. 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]);
>> + return rc;
>> +}
Ah, nr_pages is updated here but we don't return it to the caller!
That should be fixed at first.
>> +
>> 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;
>> + size_t len, cur_len;
>> ssize_t total_written = 0;
>> loff_t offset;
>> struct cifsFileInfo *open_file;
>> @@ -2464,8 +2509,6 @@ 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);
>> @@ -2480,46 +2523,14 @@ 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) {
>> + rc = wdata_fill_from_iovec(wdata, from, &cur_len, nr_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.
>> - */
>> - 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;
>> --
>> 1.8.1.2
>>
>> --
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--
Best regards,
Pavel Shilovsky.
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