On 16/04/18 08:24, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
> 
> Read configuration values from Xen store according
> to xen/interface/io/sndif.h protocol:
>   - introduce configuration structures for different
>     components, e.g. sound card, device, stream
>   - read PCM HW parameters, e.g rate, format etc.
>   - detect stream type (capture/playback)
>   - read device and card parameters
> 
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
> ---
>  sound/xen/Makefile            |   3 +-
>  sound/xen/xen_snd_front.c     |   7 +
>  sound/xen/xen_snd_front.h     |   4 +
>  sound/xen/xen_snd_front_cfg.c | 517 
> ++++++++++++++++++++++++++++++++++++++++++
>  sound/xen/xen_snd_front_cfg.h |  46 ++++
>  5 files changed, 576 insertions(+), 1 deletion(-)
>  create mode 100644 sound/xen/xen_snd_front_cfg.c
>  create mode 100644 sound/xen/xen_snd_front_cfg.h
> 
> diff --git a/sound/xen/Makefile b/sound/xen/Makefile
> index 4507ef3c27fd..06705bef61fa 100644
> --- a/sound/xen/Makefile
> +++ b/sound/xen/Makefile
> @@ -1,5 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0 OR MIT
>  
> -snd_xen_front-objs := xen_snd_front.o
> +snd_xen_front-objs := xen_snd_front.o \
> +                   xen_snd_front_cfg.o
>  
>  obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o
> diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c
> index f406a8f52c51..65d2494a9d14 100644
> --- a/sound/xen/xen_snd_front.c
> +++ b/sound/xen/xen_snd_front.c
> @@ -25,6 +25,13 @@ static void xen_snd_drv_fini(struct xen_snd_front_info 
> *front_info)
>  
>  static int sndback_initwait(struct xen_snd_front_info *front_info)
>  {
> +     int num_streams;
> +     int ret;
> +
> +     ret = xen_snd_front_cfg_card(front_info, &num_streams);
> +     if (ret < 0)
> +             return ret;
> +
>       return 0;
>  }
>  
> diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h
> index 4ae204b23d32..b52226cb30bc 100644
> --- a/sound/xen/xen_snd_front.h
> +++ b/sound/xen/xen_snd_front.h
> @@ -11,8 +11,12 @@
>  #ifndef __XEN_SND_FRONT_H
>  #define __XEN_SND_FRONT_H
>  
> +#include "xen_snd_front_cfg.h"
> +
>  struct xen_snd_front_info {
>       struct xenbus_device *xb_dev;
> +
> +     struct xen_front_cfg_card cfg;
>  };
>  
>  #endif /* __XEN_SND_FRONT_H */
> diff --git a/sound/xen/xen_snd_front_cfg.c b/sound/xen/xen_snd_front_cfg.c
> new file mode 100644
> index 000000000000..d461985afffa
> --- /dev/null
> +++ b/sound/xen/xen_snd_front_cfg.c
> @@ -0,0 +1,517 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +
> +/*
> + * Xen para-virtual sound device
> + *
> + * Copyright (C) 2016-2018 EPAM Systems Inc.
> + *
> + * Author: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
> + */
> +
> +#include <xen/xenbus.h>
> +
> +#include <xen/interface/io/sndif.h>
> +
> +#include "xen_snd_front.h"
> +#include "xen_snd_front_cfg.h"
> +
> +/* maximum number of supported streams */

Comment style (multiple times below, too):
Start with a capital letter and end sentences with a full stop.

> +#define VSND_MAX_STREAM              8
> +
> +struct cfg_hw_sample_rate {
> +     const char *name;
> +     unsigned int mask;
> +     unsigned int value;
> +};
> +
> +static const struct cfg_hw_sample_rate CFG_HW_SUPPORTED_RATES[] = {
> +     { .name = "5512",   .mask = SNDRV_PCM_RATE_5512,   .value = 5512 },
> +     { .name = "8000",   .mask = SNDRV_PCM_RATE_8000,   .value = 8000 },
> +     { .name = "11025",  .mask = SNDRV_PCM_RATE_11025,  .value = 11025 },
> +     { .name = "16000",  .mask = SNDRV_PCM_RATE_16000,  .value = 16000 },
> +     { .name = "22050",  .mask = SNDRV_PCM_RATE_22050,  .value = 22050 },
> +     { .name = "32000",  .mask = SNDRV_PCM_RATE_32000,  .value = 32000 },
> +     { .name = "44100",  .mask = SNDRV_PCM_RATE_44100,  .value = 44100 },
> +     { .name = "48000",  .mask = SNDRV_PCM_RATE_48000,  .value = 48000 },
> +     { .name = "64000",  .mask = SNDRV_PCM_RATE_64000,  .value = 64000 },
> +     { .name = "96000",  .mask = SNDRV_PCM_RATE_96000,  .value = 96000 },
> +     { .name = "176400", .mask = SNDRV_PCM_RATE_176400, .value = 176400 },
> +     { .name = "192000", .mask = SNDRV_PCM_RATE_192000, .value = 192000 },
> +};
> +
> +struct cfg_hw_sample_format {
> +     const char *name;
> +     u64 mask;
> +};
> +
> +static const struct cfg_hw_sample_format CFG_HW_SUPPORTED_FORMATS[] = {
> +     {
> +             .name = XENSND_PCM_FORMAT_U8_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U8
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S8_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S8
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_U16_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U16_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_U16_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U16_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S16_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S16_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S16_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S16_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_U24_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U24_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_U24_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U24_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S24_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S24_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S24_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S24_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_U32_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U32_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_U32_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_U32_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S32_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S32_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_S32_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_S32_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_A_LAW_STR,
> +             .mask = SNDRV_PCM_FMTBIT_A_LAW
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_MU_LAW_STR,
> +             .mask = SNDRV_PCM_FMTBIT_MU_LAW
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_F32_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_FLOAT_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_F32_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_FLOAT_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_F64_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_FLOAT64_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_F64_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_FLOAT64_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE_STR,
> +             .mask = SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_IMA_ADPCM_STR,
> +             .mask = SNDRV_PCM_FMTBIT_IMA_ADPCM
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_MPEG_STR,
> +             .mask = SNDRV_PCM_FMTBIT_MPEG
> +     },
> +     {
> +             .name = XENSND_PCM_FORMAT_GSM_STR,
> +             .mask = SNDRV_PCM_FMTBIT_GSM
> +     },
> +};
> +
> +static void cfg_hw_rates(char *list, unsigned int len,
> +                      const char *path, struct snd_pcm_hardware *pcm_hw)
> +{
> +     char *cur_rate;
> +     unsigned int cur_mask;
> +     unsigned int cur_value;
> +     unsigned int rates;
> +     unsigned int rate_min;
> +     unsigned int rate_max;
> +     int i;
> +
> +     rates = 0;
> +     rate_min = -1;
> +     rate_max = 0;
> +     while ((cur_rate = strsep(&list, XENSND_LIST_SEPARATOR))) {
> +             for (i = 0; i < ARRAY_SIZE(CFG_HW_SUPPORTED_RATES); i++)
> +                     if (!strncasecmp(cur_rate,
> +                                      CFG_HW_SUPPORTED_RATES[i].name,
> +                                      XENSND_SAMPLE_RATE_MAX_LEN)) {
> +                             cur_mask = CFG_HW_SUPPORTED_RATES[i].mask;
> +                             cur_value = CFG_HW_SUPPORTED_RATES[i].value;
> +                             rates |= cur_mask;
> +                             if (rate_min > cur_value)
> +                                     rate_min = cur_value;
> +                             if (rate_max < cur_value)
> +                                     rate_max = cur_value;
> +                     }
> +     }
> +
> +     if (rates) {
> +             pcm_hw->rates = rates;
> +             pcm_hw->rate_min = rate_min;
> +             pcm_hw->rate_max = rate_max;
> +     }
> +}
> +
> +static void cfg_formats(char *list, unsigned int len,
> +                     const char *path, struct snd_pcm_hardware *pcm_hw)
> +{
> +     u64 formats;
> +     char *cur_format;
> +     int i;
> +
> +     formats = 0;
> +     while ((cur_format = strsep(&list, XENSND_LIST_SEPARATOR))) {
> +             for (i = 0; i < ARRAY_SIZE(CFG_HW_SUPPORTED_FORMATS); i++)
> +                     if (!strncasecmp(cur_format,
> +                                      CFG_HW_SUPPORTED_FORMATS[i].name,
> +                                      XENSND_SAMPLE_FORMAT_MAX_LEN))
> +                             formats |= CFG_HW_SUPPORTED_FORMATS[i].mask;
> +     }
> +
> +     if (formats)
> +             pcm_hw->formats = formats;
> +}
> +
> +#define MAX_BUFFER_SIZE              (64 * 1024)
> +#define MIN_PERIOD_SIZE              64
> +#define MAX_PERIOD_SIZE              MAX_BUFFER_SIZE
> +#define USE_FORMATS          (SNDRV_PCM_FMTBIT_U8 | \
> +                              SNDRV_PCM_FMTBIT_S16_LE)
> +#define USE_RATE             (SNDRV_PCM_RATE_CONTINUOUS | \
> +                              SNDRV_PCM_RATE_8000_48000)
> +#define USE_RATE_MIN         5512
> +#define USE_RATE_MAX         48000
> +#define USE_CHANNELS_MIN     1
> +#define USE_CHANNELS_MAX     2
> +#define USE_PERIODS_MIN              2
> +#define USE_PERIODS_MAX              (MAX_BUFFER_SIZE / MIN_PERIOD_SIZE)
> +
> +static const struct snd_pcm_hardware SND_DRV_PCM_HW_DEFAULT = {
> +     .info = (SNDRV_PCM_INFO_MMAP |
> +              SNDRV_PCM_INFO_INTERLEAVED |
> +              SNDRV_PCM_INFO_RESUME |
> +              SNDRV_PCM_INFO_MMAP_VALID),
> +     .formats = USE_FORMATS,
> +     .rates = USE_RATE,
> +     .rate_min = USE_RATE_MIN,
> +     .rate_max = USE_RATE_MAX,
> +     .channels_min = USE_CHANNELS_MIN,
> +     .channels_max = USE_CHANNELS_MAX,
> +     .buffer_bytes_max = MAX_BUFFER_SIZE,
> +     .period_bytes_min = MIN_PERIOD_SIZE,
> +     .period_bytes_max = MAX_PERIOD_SIZE,
> +     .periods_min = USE_PERIODS_MIN,
> +     .periods_max = USE_PERIODS_MAX,
> +     .fifo_size = 0,
> +};
> +
> +static void cfg_read_pcm_hw(const char *path,
> +                         struct snd_pcm_hardware *parent_pcm_hw,
> +                         struct snd_pcm_hardware *pcm_hw)
> +{
> +     char *list;
> +     int val;
> +     size_t buf_sz;
> +     unsigned int len;
> +
> +     /* inherit parent's PCM HW and read overrides from XenStore */
> +     if (parent_pcm_hw)
> +             *pcm_hw = *parent_pcm_hw;
> +     else
> +             *pcm_hw = SND_DRV_PCM_HW_DEFAULT;
> +
> +     val = xenbus_read_unsigned(path, XENSND_FIELD_CHANNELS_MIN, 0);
> +     if (val)
> +             pcm_hw->channels_min = val;
> +
> +     val = xenbus_read_unsigned(path, XENSND_FIELD_CHANNELS_MAX, 0);
> +     if (val)
> +             pcm_hw->channels_max = val;
> +
> +     list = xenbus_read(XBT_NIL, path, XENSND_FIELD_SAMPLE_RATES, &len);
> +     if (!IS_ERR(list)) {
> +             cfg_hw_rates(list, len, path, pcm_hw);
> +             kfree(list);
> +     }
> +
> +     list = xenbus_read(XBT_NIL, path, XENSND_FIELD_SAMPLE_FORMATS, &len);
> +     if (!IS_ERR(list)) {
> +             cfg_formats(list, len, path, pcm_hw);
> +             kfree(list);
> +     }
> +
> +     buf_sz = xenbus_read_unsigned(path, XENSND_FIELD_BUFFER_SIZE, 0);
> +     if (buf_sz)
> +             pcm_hw->buffer_bytes_max = buf_sz;
> +
> +     /* update configuration to match new values */
> +     if (pcm_hw->channels_min > pcm_hw->channels_max)
> +             pcm_hw->channels_min = pcm_hw->channels_max;
> +
> +     if (pcm_hw->rate_min > pcm_hw->rate_max)
> +             pcm_hw->rate_min = pcm_hw->rate_max;
> +
> +     pcm_hw->period_bytes_max = pcm_hw->buffer_bytes_max;
> +
> +     pcm_hw->periods_max = pcm_hw->period_bytes_max /
> +             pcm_hw->period_bytes_min;
> +}
> +
> +static int cfg_get_stream_type(const char *path, int index,
> +                            int *num_pb, int *num_cap)
> +{
> +     char *str = NULL;
> +     char *stream_path;
> +     int ret;
> +
> +     *num_pb = 0;
> +     *num_cap = 0;
> +     stream_path = kasprintf(GFP_KERNEL, "%s/%d", path, index);
> +     if (!stream_path) {
> +             ret = -ENOMEM;
> +             goto fail;
> +     }
> +
> +     str = xenbus_read(XBT_NIL, stream_path, XENSND_FIELD_TYPE, NULL);
> +     if (IS_ERR(str)) {
> +             ret = -EINVAL;

Is this correct? Do you want to return -EINVAL in case xenbus_read()
failed with e.g. -ENOMEM?

> +             goto fail;
> +     }
> +
> +     if (!strncasecmp(str, XENSND_STREAM_TYPE_PLAYBACK,
> +                      sizeof(XENSND_STREAM_TYPE_PLAYBACK))) {
> +             (*num_pb)++;
> +     } else if (!strncasecmp(str, XENSND_STREAM_TYPE_CAPTURE,
> +                           sizeof(XENSND_STREAM_TYPE_CAPTURE))) {
> +             (*num_cap)++;
> +     } else {
> +             ret = -EINVAL;
> +             goto fail;
> +     }
> +     ret = 0;
> +
> +fail:
> +     kfree(stream_path);
> +     kfree(str);
> +     return ret;
> +}
> +
> +static int cfg_stream(struct xen_snd_front_info *front_info,
> +                   struct xen_front_cfg_pcm_instance *pcm_instance,
> +                   const char *path, int index, int *cur_pb, int *cur_cap,
> +                   int *stream_cnt)
> +{
> +     char *str = NULL;
> +     char *stream_path;
> +     struct xen_front_cfg_stream *stream;
> +     int ret;
> +
> +     stream_path = devm_kasprintf(&front_info->xb_dev->dev,
> +                                  GFP_KERNEL, "%s/%d", path, index);
> +     if (!stream_path) {
> +             ret = -ENOMEM;
> +             goto fail;
> +     }
> +
> +     str = xenbus_read(XBT_NIL, stream_path, XENSND_FIELD_TYPE, NULL);
> +     if (IS_ERR(str)) {
> +             ret = -EINVAL;

Same as above.

> +             goto fail;
> +     }
> +
> +     if (!strncasecmp(str, XENSND_STREAM_TYPE_PLAYBACK,
> +                      sizeof(XENSND_STREAM_TYPE_PLAYBACK))) {
> +             stream = &pcm_instance->streams_pb[(*cur_pb)++];
> +     } else if (!strncasecmp(str, XENSND_STREAM_TYPE_CAPTURE,
> +                           sizeof(XENSND_STREAM_TYPE_CAPTURE))) {
> +             stream = &pcm_instance->streams_cap[(*cur_cap)++];
> +     } else {
> +             ret = -EINVAL;
> +             goto fail;
> +     }

Until here this function looks very much like cfg_get_stream_type().
Can't they use a common sub-function?

> +
> +     /* get next stream index */
> +     stream->index = (*stream_cnt)++;
> +     stream->xenstore_path = stream_path;
> +     /*
> +      * check in Xen store if PCM HW configuration exists for this stream
> +      * and update if so, e.g. we inherit all values from device's PCM HW,
> +      * but can still override some of the values for the stream
> +      */
> +     cfg_read_pcm_hw(stream->xenstore_path,
> +                     &pcm_instance->pcm_hw, &stream->pcm_hw);
> +     ret = 0;
> +
> +fail:
> +     kfree(str);
> +     return ret;
> +}
> +
> +static int cfg_device(struct xen_snd_front_info *front_info,
> +                   struct xen_front_cfg_pcm_instance *pcm_instance,
> +                   struct snd_pcm_hardware *parent_pcm_hw,
> +                   const char *path, int node_index, int *stream_cnt)
> +{
> +     char *str;
> +     char *device_path;
> +     int ret, i, num_streams;
> +     int num_pb, num_cap;
> +     int cur_pb, cur_cap;
> +     char node[3];
> +
> +     device_path = kasprintf(GFP_KERNEL, "%s/%d", path, node_index);
> +     if (!device_path)
> +             return -ENOMEM;
> +
> +     str = xenbus_read(XBT_NIL, device_path, XENSND_FIELD_DEVICE_NAME, NULL);
> +     if (!IS_ERR(str)) {
> +             strncpy(pcm_instance->name, str, sizeof(pcm_instance->name));
> +             kfree(str);
> +     }
> +
> +     pcm_instance->device_id = node_index;
> +
> +     /*
> +      * check in Xen store if PCM HW configuration exists for this device
> +      * and update if so, e.g. we inherit all values from card's PCM HW,
> +      * but can still override some of the values for the device
> +      */
> +     cfg_read_pcm_hw(device_path, parent_pcm_hw, &pcm_instance->pcm_hw);
> +
> +     /* find out how many streams were configured in Xen store */
> +     num_streams = 0;
> +     do {
> +             snprintf(node, sizeof(node), "%d", num_streams);
> +             if (!xenbus_exists(XBT_NIL, device_path, node))
> +                     break;
> +
> +             num_streams++;
> +     } while (num_streams < VSND_MAX_STREAM);
> +
> +     pcm_instance->num_streams_pb = 0;
> +     pcm_instance->num_streams_cap = 0;
> +     /* get number of playback and capture streams */
> +     for (i = 0; i < num_streams; i++) {
> +             ret = cfg_get_stream_type(device_path, i, &num_pb, &num_cap);
> +             if (ret < 0)
> +                     goto fail;
> +
> +             pcm_instance->num_streams_pb += num_pb;
> +             pcm_instance->num_streams_cap += num_cap;
> +     }
> +
> +     if (pcm_instance->num_streams_pb) {
> +             pcm_instance->streams_pb =
> +                             devm_kcalloc(&front_info->xb_dev->dev,
> +                                          pcm_instance->num_streams_pb,
> +                                          sizeof(struct 
> xen_front_cfg_stream),
> +                                          GFP_KERNEL);
> +             if (!pcm_instance->streams_pb) {
> +                     ret = -ENOMEM;
> +                     goto fail;
> +             }
> +     }
> +
> +     if (pcm_instance->num_streams_cap) {
> +             pcm_instance->streams_cap =
> +                             devm_kcalloc(&front_info->xb_dev->dev,
> +                                          pcm_instance->num_streams_cap,
> +                                          sizeof(struct 
> xen_front_cfg_stream),
> +                                          GFP_KERNEL);
> +             if (!pcm_instance->streams_cap) {
> +                     ret = -ENOMEM;
> +                     goto fail;
> +             }
> +     }
> +
> +     cur_pb = 0;
> +     cur_cap = 0;
> +     for (i = 0; i < num_streams; i++) {
> +             ret = cfg_stream(front_info, pcm_instance, device_path, i,
> +                              &cur_pb, &cur_cap, stream_cnt);
> +             if (ret < 0)
> +                     goto fail;
> +     }
> +     ret = 0;
> +
> +fail:
> +     kfree(device_path);
> +     return ret;
> +}
> +
> +int xen_snd_front_cfg_card(struct xen_snd_front_info *front_info,
> +                        int *stream_cnt)
> +{
> +     struct xenbus_device *xb_dev = front_info->xb_dev;
> +     struct xen_front_cfg_card *cfg = &front_info->cfg;
> +     int ret, num_devices, i;
> +     char node[3];
> +
> +     *stream_cnt = 0;
> +     num_devices = 0;
> +     do {
> +             snprintf(node, sizeof(node), "%d", num_devices);
> +             if (!xenbus_exists(XBT_NIL, xb_dev->nodename, node))
> +                     break;
> +
> +             num_devices++;
> +     } while (num_devices < SNDRV_PCM_DEVICES);
> +
> +     if (!num_devices) {
> +             dev_warn(&xb_dev->dev,
> +                      "No devices configured for sound card at %s\n",
> +                      xb_dev->nodename);
> +             return -ENODEV;
> +     }
> +
> +     /* start from default PCM HW configuration for the card */
> +     cfg_read_pcm_hw(xb_dev->nodename, NULL, &cfg->pcm_hw);
> +
> +     cfg->pcm_instances =
> +                     devm_kcalloc(&front_info->xb_dev->dev, num_devices,
> +                                  sizeof(struct xen_front_cfg_pcm_instance),
> +                                  GFP_KERNEL);
> +     if (!cfg->pcm_instances)
> +             return -ENOMEM;
> +
> +     for (i = 0; i < num_devices; i++) {
> +             ret = cfg_device(front_info, &cfg->pcm_instances[i],
> +                              &cfg->pcm_hw, xb_dev->nodename, i, stream_cnt);
> +             if (ret < 0)
> +                     return ret;

Who will free all the memory allocated until now in case of an error?

And I think when removing the device freeing the memory is missing, too.


Juergen

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