From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleksandr Andrushchenko Subject: Re: [PATCH v2 2/5] ALSA: xen-front: Read sound driver configuration from Xen store Date: Tue, 17 Apr 2018 11:42:37 +0300 Message-ID: <2c37fff3-9dfe-f904-d06f-7751d5e9e002@gmail.com> References: <20180416062453.24743-1-andr2000@gmail.com> <20180416062453.24743-3-andr2000@gmail.com> <451f4f4b-646e-0058-e24f-d9ae918f583f@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <451f4f4b-646e-0058-e24f-d9ae918f583f@suse.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Juergen Gross , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, perex@perex.cz, tiwai@suse.com Cc: Oleksandr Andrushchenko List-Id: alsa-devel@alsa-project.org On 04/16/2018 03:55 PM, Juergen Gross wrote: > On 16/04/18 08:24, Oleksandr Andrushchenko wrote: >> From: Oleksandr Andrushchenko >> >> 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 >> --- >> 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 >> + */ >> + >> +#include >> + >> +#include >> + >> +#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. will fix >> +#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? will return PTR_ERR(str) >> + 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. will return PTR_ERR(str) > >> + 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? Not really, because cfg_get_stream_type uses kasprintf for strings and this one devm_kasprintf. Trying to make a common sub-func doesn't make sense to me > >> + >> + /* 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? The memory is allocated with devm_xxx functions, so it will be freed on device destructions automatically > > And I think when removing the device freeing the memory is missing, too. Same as above, the kernel will take care of it while destroying the device > > Juergen