diff options
author | Stephen Hemminger <stephen@networkplumber.org> | 2018-02-05 10:40:27 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-06 09:57:17 -0800 |
commit | 37b96a4931dba07cebbf07092e55d1562155412b (patch) | |
tree | 865b31a14739197399ccc79d62d9e5ad555dbca6 /drivers/uio | |
parent | cf21be919c5960da2eb7bc91f8056adb27b56712 (diff) |
uio_hv_generic: support sub-channels
Use sysfs to allow supporting sub-channels. The userspace application
makes request to host to create sub-channels and the UIO kernel
driver populates the sysfs per-channel directory with a binary
attribute file that can be used to read/write ring.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/uio')
-rw-r--r-- | drivers/uio/uio_hv_generic.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c index 8ca549032c27..f695a7e8c314 100644 --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -121,6 +121,94 @@ static void hv_uio_rescind(struct vmbus_channel *channel) uio_event_notify(&pdata->info); } +/* + * Handle fault when looking for sub channel ring buffer + * Subchannel ring buffer is same as resource 0 which is main ring buffer + * This is derived from uio_vma_fault + */ +static int hv_uio_vma_fault(struct vm_fault *vmf) +{ + struct vm_area_struct *vma = vmf->vma; + void *ring_buffer = vma->vm_private_data; + struct page *page; + void *addr; + + addr = ring_buffer + (vmf->pgoff << PAGE_SHIFT); + page = virt_to_page(addr); + get_page(page); + vmf->page = page; + return 0; +} + +static const struct vm_operations_struct hv_uio_vm_ops = { + .fault = hv_uio_vma_fault, +}; + +/* Sysfs API to allow mmap of the ring buffers */ +static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, + struct vm_area_struct *vma) +{ + struct vmbus_channel *channel + = container_of(kobj, struct vmbus_channel, kobj); + unsigned long requested_pages, actual_pages; + + if (vma->vm_end < vma->vm_start) + return -EINVAL; + + /* only allow 0 for now */ + if (vma->vm_pgoff > 0) + return -EINVAL; + + requested_pages = vma_pages(vma); + actual_pages = 2 * HV_RING_SIZE; + if (requested_pages > actual_pages) + return -EINVAL; + + vma->vm_private_data = channel->ringbuffer_pages; + vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_ops = &hv_uio_vm_ops; + return 0; +} + +static struct bin_attribute ring_buffer_bin_attr __ro_after_init = { + .attr = { + .name = "ring", + .mode = 0600, + /* size is set at init time */ + }, + .mmap = hv_uio_ring_mmap, +}; + +/* Callback from VMBUS subystem when new channel created. */ +static void +hv_uio_new_channel(struct vmbus_channel *new_sc) +{ + struct hv_device *hv_dev = new_sc->primary_channel->device_obj; + struct device *device = &hv_dev->device; + struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); + const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE; + int ret; + + /* Create host communication ring */ + ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0, + hv_uio_channel_cb, pdata); + if (ret) { + dev_err(device, "vmbus_open subchannel failed: %d\n", ret); + return; + } + + /* Disable interrupts on sub channel */ + new_sc->inbound.ring_buffer->interrupt_mask = 1; + set_channel_read_mode(new_sc, HV_CALL_ISR); + + ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr); + if (ret) { + dev_err(device, "sysfs create ring bin file failed; %d\n", ret); + vmbus_close(new_sc); + } +} + static void hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata) { @@ -236,6 +324,7 @@ hv_uio_probe(struct hv_device *dev, } vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind); + vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel); hv_set_drvdata(dev, pdata); |