Revert "Add implementation of poll() to dma_buf using KDS"

This reverts commit 5d1bb28fa72400006b3956ab7d869dffd091af23.

There are no users of dma-buf poll(), this isn't upstream, and we aren't
carrying it forward to 3.8.

Revert from 3.4 to keep 3.8 & 3.4 more consistent.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
BUG=none
TEST=none

Change-Id: Ia6628aef06f5ee228f3ac479bfa0e75b45573f04
Reviewed-on: https://gerrit.chromium.org/gerrit/50187
Tested-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Commit-Queue: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>

diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 4defa66..477d73e 100644 (file)
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -27,10 +27,6 @@
 #include <linux/dma-buf.h>
 #include <linux/anon_inodes.h>
 #include <linux/export.h>
-#ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
-#include <linux/poll.h>
-#include <linux/sched.h>
-#endif
 
 static inline int is_dma_buf_file(struct file *);
 
@@ -45,7 +41,6 @@ static int dma_buf_release(struct inode *inode, struct file *file)
 
        dmabuf->ops->release(dmabuf);
 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
-       kds_callback_term(&dmabuf->kds_cb);
        kds_resource_term(&dmabuf->kds);
 #endif
        kfree(dmabuf);
@@ -69,95 +64,9 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
        return dmabuf->ops->mmap(dmabuf, vma);
 }
 
-#ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
-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;
-}
-#endif
-
 static const struct file_operations dma_buf_fops = {
        .release        = dma_buf_release,
        .mmap           = dma_buf_mmap_internal,
-#ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
-       .poll           = dma_buf_poll,
-#endif
 };
 
 /*
@@ -215,10 +124,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
        INIT_LIST_HEAD(&dmabuf->attachments);
 
 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
-       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);
 #endif
 
        return dmabuf;

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 5eb40e7..34073f6 100644 (file)
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -32,7 +32,6 @@
 #include <linux/fs.h>
 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
 #include <linux/kds.h>
-#include <linux/wait.h>
 #endif
 
 struct device;
@@ -127,9 +126,6 @@ struct dma_buf {
        struct mutex lock;
 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
        struct kds_resource kds;
-       wait_queue_head_t wq_exclusive;
-       wait_queue_head_t wq_shared;
-       struct kds_callback kds_cb;
 #endif
        void *priv;
 };