On Thu, 11 Feb 2021 14:24:40 +0200 Alexandru Ardelean <[email protected]> wrote:
> If we want to merge the attributes of the buffer/ and scan_elements/ > directories, we'll need to count all attributes first, then (depending on > the attribute group) either allocate 2 attribute groups, or a single one. > Historically an IIO buffer was described by 2 subdirectories under > /sys/bus/iio/iio:devicesX (i.e. buffer/ and scan_elements/); these subdirs > were actually 2 separate attribute groups on the iio_buffer object. > > Moving forward, if we want to allow more than one buffer per IIO device, > keeping 2 subdirectories for each IIO buffer is a bit cumbersome > (especially for userpace ABI). So, we will merge the attributes of these 2 > subdirs under a /sys/bus/iio/iio:devicesX/bufferY subdirectory. To do this, > we need to count all attributes first, and then distribute them based on > which buffer this is. For the first buffer, we'll need to also allocate the > legacy 2 attribute groups (for buffer/ and scan_elements/), and also a > /sys/bus/iio/iio:devicesX/buffer0 attribute group. > > For buffer1 and above, just a single attribute group will be allocated (the > merged one). > > Signed-off-by: Alexandru Ardelean <[email protected]> One totally trivial thing noticed in here. If we happen to respin please tidy it up, if I take these as is I 'might' tweak it, or I might not bother depending on what mood I'm in later today. Jonathan > --- > drivers/iio/industrialio-buffer.c | 71 ++++++++++++++++--------------- > 1 file changed, 37 insertions(+), 34 deletions(-) > > diff --git a/drivers/iio/industrialio-buffer.c > b/drivers/iio/industrialio-buffer.c > index cc846988fdb9..23f22be62cc7 100644 > --- a/drivers/iio/industrialio-buffer.c > +++ b/drivers/iio/industrialio-buffer.c > @@ -1257,41 +1257,16 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct > iio_buffer *buffer, > { > struct iio_dev_attr *p; > struct attribute **attr; > - int ret, i, attrn, attrcount; > + int ret, i, attrn, scan_el_attrcount, buffer_attrcount; > const struct iio_chan_spec *channels; > > - attrcount = 0; > + buffer_attrcount = 0; > if (buffer->attrs) { > - while (buffer->attrs[attrcount] != NULL) > - attrcount++; > + while (buffer->attrs[buffer_attrcount] != NULL) > + buffer_attrcount++; > } > > - attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1, > - sizeof(struct attribute *), GFP_KERNEL); > - if (!attr) > - return -ENOMEM; > - > - memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs)); > - if (!buffer->access->set_length) > - attr[0] = &dev_attr_length_ro.attr; > - > - if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK) > - attr[2] = &dev_attr_watermark_ro.attr; > - > - if (buffer->attrs) > - memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs, > - sizeof(struct attribute *) * attrcount); > - > - attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL; > - > - buffer->buffer_group.name = "buffer"; > - buffer->buffer_group.attrs = attr; > - > - ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group); > - if (ret) > - goto error_free_buffer_attrs; > - > - attrcount = 0; > + scan_el_attrcount = 0; > INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list); > channels = indio_dev->channels; > if (channels) { > @@ -1304,7 +1279,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct > iio_buffer *buffer, > &channels[i]); > if (ret < 0) > goto error_cleanup_dynamic; > - attrcount += ret; > + scan_el_attrcount += ret; > if (channels[i].type == IIO_TIMESTAMP) > indio_dev->scan_index_timestamp = > channels[i].scan_index; > @@ -1319,9 +1294,37 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct > iio_buffer *buffer, > } > } > > + attr = kcalloc(buffer_attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1, > + sizeof(struct attribute *), GFP_KERNEL); nitpick, I'd have made that sizeof(*attr) > + if (!attr) { > + ret = -ENOMEM; > + goto error_free_scan_mask; > + } > + > + memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs)); > + if (!buffer->access->set_length) > + attr[0] = &dev_attr_length_ro.attr; > + > + if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK) > + attr[2] = &dev_attr_watermark_ro.attr; > + > + if (buffer->attrs) > + memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs, > + sizeof(struct attribute *) * buffer_attrcount); > + > + buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs); > + attr[buffer_attrcount] = NULL; > + > + buffer->buffer_group.name = "buffer"; > + buffer->buffer_group.attrs = attr; > + > + ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group); > + if (ret) > + goto error_free_buffer_attrs; > + > buffer->scan_el_group.name = iio_scan_elements_group_name; > > - buffer->scan_el_group.attrs = kcalloc(attrcount + 1, > + buffer->scan_el_group.attrs = kcalloc(scan_el_attrcount + 1, > > sizeof(buffer->scan_el_group.attrs[0]), > GFP_KERNEL); > if (buffer->scan_el_group.attrs == NULL) { > @@ -1341,12 +1344,12 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct > iio_buffer *buffer, > > error_free_scan_el_attrs: > kfree(buffer->scan_el_group.attrs); > +error_free_buffer_attrs: > + kfree(buffer->buffer_group.attrs); > error_free_scan_mask: > bitmap_free(buffer->scan_mask); > error_cleanup_dynamic: > iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list); > -error_free_buffer_attrs: > - kfree(buffer->buffer_group.attrs); > > return ret; > }
