#include <linux/dma-buf.h>
#include <linux/anon_inodes.h>
#include <linux/export.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
static inline int is_dma_buf_file(struct file *);
dmabuf = file->private_data;
dmabuf->ops->release(dmabuf);
+ kds_callback_term(&dmabuf->kds_cb);
kds_resource_term(&dmabuf->kds);
kfree(dmabuf);
return 0;
return dmabuf->ops->mmap(dmabuf, vma);
}
+
+static void dma_buf_kds_cb_fn(void *param1, void *param2)
+{
+ struct kds_resource_set **rset_ptr = param1;
+ struct kds_resource_set *rset = *rset_ptr;
+ wait_queue_head_t *wait_queue = param2;
+
+ kfree(rset_ptr);
+ kds_resource_set_release(&rset);
+ wake_up(wait_queue);
+}
+
+static int dma_buf_kds_check(struct kds_resource *kds,
+ unsigned long exclusive, int *poll_ret)
+{
+ /* Synchronous wait with 0 timeout - poll availability */
+ struct kds_resource_set *rset = kds_waitall(1, &exclusive, &kds, 0);
+
+ if (IS_ERR(rset))
+ return POLLERR;
+
+ if (rset) {
+ kds_resource_set_release(&rset);
+ *poll_ret = POLLIN | POLLRDNORM;
+ if (exclusive)
+ *poll_ret |= POLLOUT | POLLWRNORM;
+ return 1;
+ } else {
+ return 0;
+ }
+}
+
+static unsigned int dma_buf_poll(struct file *file,
+ struct poll_table_struct *wait)
+{
+ struct dma_buf *dmabuf;
+ struct kds_resource *kds;
+ unsigned int ret = 0;
+
+ if (!is_dma_buf_file(file))
+ return POLLERR;
+
+ dmabuf = file->private_data;
+ kds = &dmabuf->kds;
+
+ if (poll_does_not_wait(wait)) {
+ /* Check for exclusive access (superset of shared) first */
+ if (!dma_buf_kds_check(kds, 1ul, &ret))
+ dma_buf_kds_check(kds, 0ul, &ret);
+ } else {
+ int events = poll_requested_events(wait);
+ unsigned long exclusive;
+ wait_queue_head_t *wq;
+ struct kds_resource_set **rset_ptr =
+ kmalloc(sizeof(*rset_ptr), GFP_KERNEL);
+
+ if (!rset_ptr)
+ return POLL_ERR;
+
+ if (events & POLLOUT) {
+ wq = &dmabuf->wq_exclusive;
+ exclusive = 1;
+ } else {
+ wq = &dmabuf->wq_shared;
+ exclusive = 0;
+ }
+ poll_wait(file, wq, wait);
+ ret = kds_async_waitall(rset_ptr, KDS_FLAG_LOCKED_WAIT,
+ &dmabuf->kds_cb, rset_ptr, wq, 1, &exclusive,
+ &kds);
+
+ if (IS_ERR_VALUE(ret)) {
+ ret = POLL_ERR;
+ kfree(rset_ptr);
+ } else {
+ /* Can't allow access until callback */
+ ret = 0;
+ }
+ }
+ return ret;
+}
+
static const struct file_operations dma_buf_fops = {
.release = dma_buf_release,
.mmap = dma_buf_mmap_internal,
+ .poll = dma_buf_poll,
};
/*
mutex_init(&dmabuf->lock);
INIT_LIST_HEAD(&dmabuf->attachments);
+ init_waitqueue_head(&dmabuf->wq_exclusive);
+ init_waitqueue_head(&dmabuf->wq_shared);
kds_resource_init(&dmabuf->kds);
+ kds_callback_init(&dmabuf->kds_cb, 1, dma_buf_kds_cb_fn);
return dmabuf;
}