Re: [PATCH 1/3] drivers/staging/cx25821: Use kstrdup

From: Julia Lawall
Date: Mon Oct 18 2010 - 13:44:59 EST

On Mon, 18 Oct 2010, Joe Perches wrote:

> Perhaps it's more readable code to recheck the
> field name flag and introduce a temporary
> char *fname so the slightly unusual reuse of
> field = kstrdup(field, GFP)
> becomes
> field = kstrdup(fname, GFP)

Before I had a local variable filename. I preferred that because I felt
uneasy about putting both statically and dynamically allocated memory in
the same field. But it does mean adding a new local variable.

I'm not sure to understand "recheck the field name flag", though.

julia


> ---
> drivers/staging/cx25821/cx25821-audio-upstream.c | 34 +++---------
> .../staging/cx25821/cx25821-video-upstream-ch2.c | 55 +++++++-------------
> drivers/staging/cx25821/cx25821-video-upstream.c | 53 +++++++------------
> 3 files changed, 47 insertions(+), 95 deletions(-)
>
> diff --git a/drivers/staging/cx25821/cx25821-audio-upstream.c b/drivers/staging/cx25821/cx25821-audio-upstream.c
> index 27087db..180840f 100644
> --- a/drivers/staging/cx25821/cx25821-audio-upstream.c
> +++ b/drivers/staging/cx25821/cx25821-audio-upstream.c
> @@ -723,8 +723,6 @@ int cx25821_audio_upstream_init(struct cx25821_dev *dev, int channel_select)
> {
> struct sram_channel *sram_ch;
> int retval = 0;
> - int err = 0;
> - int str_length = 0;
>
> if (dev->_audio_is_running) {
> printk(KERN_WARNING "Audio Channel is still running so return!\n");
> @@ -752,28 +750,14 @@ int cx25821_audio_upstream_init(struct cx25821_dev *dev, int channel_select)
> dev->_audio_lines_count = LINES_PER_AUDIO_BUFFER;
> _line_size = AUDIO_LINE_SIZE;
>
> - if (dev->input_audiofilename) {
> - str_length = strlen(dev->input_audiofilename);
> - dev->_audiofilename = kmalloc(str_length + 1, GFP_KERNEL);
> -
> - if (!dev->_audiofilename)
> - goto error;
> -
> - memcpy(dev->_audiofilename, dev->input_audiofilename,
> - str_length + 1);
> -
> - /* Default if filename is empty string */
> - if (strcmp(dev->input_audiofilename, "") == 0)
> - dev->_audiofilename = "/root/audioGOOD.wav";
> -
> - } else {
> - str_length = strlen(_defaultAudioName);
> - dev->_audiofilename = kmalloc(str_length + 1, GFP_KERNEL);
> -
> - if (!dev->_audiofilename)
> - goto error;
> -
> - memcpy(dev->_audiofilename, _defaultAudioName, str_length + 1);
> + if (!dev->input_audiofilename || *dev->input_audiofilename == 0)
> + dev->_audiofilename = _defaultAudioName;
> + else
> + dev->_audiofilename = dev->input_audiofilename;
> + dev->_audiofilename = kstrdup(dev->_audiofilename, GFP_KERNEL);
> + if (!dev->_audiofilename) {
> + retval = -ENOMEM;
> + goto error;
> }
>
> retval =
> @@ -802,5 +786,5 @@ int cx25821_audio_upstream_init(struct cx25821_dev *dev, int channel_select)
> error:
> cx25821_dev_unregister(dev);
>
> - return err;
> + return retval;
> }
> diff --git a/drivers/staging/cx25821/cx25821-video-upstream-ch2.c b/drivers/staging/cx25821/cx25821-video-upstream-ch2.c
> index d12dbb5..fa7cd70 100644
> --- a/drivers/staging/cx25821/cx25821-video-upstream-ch2.c
> +++ b/drivers/staging/cx25821/cx25821-video-upstream-ch2.c
> @@ -747,10 +747,9 @@ int cx25821_vidupstream_init_ch2(struct cx25821_dev *dev, int channel_select,
> struct sram_channel *sram_ch;
> u32 tmp;
> int retval = 0;
> - int err = 0;
> int data_frame_size = 0;
> int risc_buffer_size = 0;
> - int str_length = 0;
> + char *fname;
>
> if (dev->_is_running_ch2) {
> printk("Video Channel is still running so return!\n");
> @@ -788,39 +787,23 @@ int cx25821_vidupstream_init_ch2(struct cx25821_dev *dev, int channel_select,
> risc_buffer_size =
> dev->_isNTSC_ch2 ? NTSC_RISC_BUF_SIZE : PAL_RISC_BUF_SIZE;
>
> - if (dev->input_filename_ch2) {
> - str_length = strlen(dev->input_filename_ch2);
> - dev->_filename_ch2 = kmalloc(str_length + 1, GFP_KERNEL);
> -
> - if (!dev->_filename_ch2)
> - goto error;
> -
> - memcpy(dev->_filename_ch2, dev->input_filename_ch2,
> - str_length + 1);
> - } else {
> - str_length = strlen(dev->_defaultname_ch2);
> - dev->_filename_ch2 = kmalloc(str_length + 1, GFP_KERNEL);
> -
> - if (!dev->_filename_ch2)
> - goto error;
> -
> - memcpy(dev->_filename_ch2, dev->_defaultname_ch2,
> - str_length + 1);
> - }
> -
> - /* Default if filename is empty string */
> - if (strcmp(dev->input_filename_ch2, "") == 0) {
> - if (dev->_isNTSC_ch2) {
> - dev->_filename_ch2 =
> - (dev->_pixel_format_ch2 ==
> - PIXEL_FRMT_411) ? "/root/vid411.yuv" :
> - "/root/vidtest.yuv";
> - } else {
> - dev->_filename_ch2 =
> - (dev->_pixel_format_ch2 ==
> - PIXEL_FRMT_411) ? "/root/pal411.yuv" :
> - "/root/pal422.yuv";
> - }
> + if (dev->input_filename_ch2 && *dev->input_filename_ch2)
> + fname = dev->input_filename_ch2;
> + else if (dev->input_filename_ch2) {
> + /* Default if filename is empty string */
> + if (dev->_isNTSC_ch2)
> + fname = (dev->_pixel_format_ch2 == PIXEL_FRMT_411) ?
> + "/root/vid411.yuv" : "/root/vidtest.yuv";
> + else
> + fname = (dev->_pixel_format_ch2 == PIXEL_FRMT_411) ?
> + "/root/pal411.yuv" : "/root/pal422.yuv";
> + } else
> + fname = dev->_defaultname_ch2;
> +
> + dev->_filename_ch2 = kstrdup(fname, GFP_KERNEL);
> + if (!dev->_filename_ch2) {
> + retval = -ENOMEM;
> + goto error;
> }
>
> retval =
> @@ -851,5 +834,5 @@ int cx25821_vidupstream_init_ch2(struct cx25821_dev *dev, int channel_select,
> error:
> cx25821_dev_unregister(dev);
>
> - return err;
> + return retval;
> }
> diff --git a/drivers/staging/cx25821/cx25821-video-upstream.c b/drivers/staging/cx25821/cx25821-video-upstream.c
> index 756a820..d51c6c1 100644
> --- a/drivers/staging/cx25821/cx25821-video-upstream.c
> +++ b/drivers/staging/cx25821/cx25821-video-upstream.c
> @@ -800,10 +800,9 @@ int cx25821_vidupstream_init_ch1(struct cx25821_dev *dev, int channel_select,
> struct sram_channel *sram_ch;
> u32 tmp;
> int retval = 0;
> - int err = 0;
> int data_frame_size = 0;
> int risc_buffer_size = 0;
> - int str_length = 0;
> + char *fname;
>
> if (dev->_is_running) {
> printk(KERN_INFO "Video Channel is still running so return!\n");
> @@ -840,37 +839,23 @@ int cx25821_vidupstream_init_ch1(struct cx25821_dev *dev, int channel_select,
> risc_buffer_size =
> dev->_isNTSC ? NTSC_RISC_BUF_SIZE : PAL_RISC_BUF_SIZE;
>
> - if (dev->input_filename) {
> - str_length = strlen(dev->input_filename);
> - dev->_filename = kmalloc(str_length + 1, GFP_KERNEL);
> -
> - if (!dev->_filename)
> - goto error;
> -
> - memcpy(dev->_filename, dev->input_filename, str_length + 1);
> - } else {
> - str_length = strlen(dev->_defaultname);
> - dev->_filename = kmalloc(str_length + 1, GFP_KERNEL);
> -
> - if (!dev->_filename)
> - goto error;
> -
> - memcpy(dev->_filename, dev->_defaultname, str_length + 1);
> - }
> -
> - /* Default if filename is empty string */
> - if (strcmp(dev->input_filename, "") == 0) {
> - if (dev->_isNTSC) {
> - dev->_filename =
> - (dev->_pixel_format ==
> - PIXEL_FRMT_411) ? "/root/vid411.yuv" :
> - "/root/vidtest.yuv";
> - } else {
> - dev->_filename =
> - (dev->_pixel_format ==
> - PIXEL_FRMT_411) ? "/root/pal411.yuv" :
> - "/root/pal422.yuv";
> - }
> + if (dev->input_filename && *dev->input_filename)
> + fname = dev->input_filename;
> + else if (dev->input_filename) {
> + /* Default if filename is empty string */
> + if (dev->_isNTSC)
> + fname = (dev->_pixel_format == PIXEL_FRMT_411) ?
> + "/root/vid411.yuv" : "/root/vidtest.yuv";
> + else
> + fname = (dev->_pixel_format == PIXEL_FRMT_411) ?
> + "/root/pal411.yuv" : "/root/pal422.yuv";
> + } else
> + fname = dev->_defaultname;
> +
> + dev->_filename = kstrdup(fname, GFP_KERNEL);
> + if (!dev->_filename) {
> + retval = -ENOMEM;
> + goto error;
> }
>
> dev->_is_running = 0;
> @@ -908,5 +893,5 @@ int cx25821_vidupstream_init_ch1(struct cx25821_dev *dev, int channel_select,
> error:
> cx25821_dev_unregister(dev);
>
> - return err;
> + return retval;
> }
>
>
>
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