drm/amdkfd: remove dead kernel-allocated signal page code

With the KFD_MMAP_TYPE_EVENTS mmap path gone, a kernel-allocated signal
page can no longer be exposed to user space, so allocate_signal_page()
and the related bookkeeping are dead code. The only remaining way to set
up a signal page is kfd_kmap_event_page()/kfd_event_page_set(), where
user space allocates the events page as a BO and passes it via the
event_page_offset of the create event IOCTL.

Remove allocate_signal_page() and require the signal page to be provided
by user space. Drop the now unused kfd_signal_page user mapping
bookkeeping (user_address/need_to_free_pages) and
kfd_event::user_signal_address.

Signed-off-by: Yongqiang Sun <Yongqiang.Sun@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
index 6088870b8c3017998b90dd2d1230cce14834e071..cf10e0902f18ab2f4af5796286018148b6fb5ffd 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
@@ -55,8 +55,6 @@ struct kfd_event_waiter {
  */
 struct kfd_signal_page {
        uint64_t *kernel_address;
-       uint64_t __user *user_address;
-       bool need_to_free_pages;
 };
 
 static uint64_t *page_slots(struct kfd_signal_page *page)
@@ -64,49 +62,19 @@ static uint64_t *page_slots(struct kfd_signal_page *page)
        return page->kernel_address;
 }
 
-static struct kfd_signal_page *allocate_signal_page(struct kfd_process *p)
-{
-       void *backing_store;
-       struct kfd_signal_page *page;
-
-       page = kzalloc_obj(*page);
-       if (!page)
-               return NULL;
-
-       backing_store = (void *) __get_free_pages(GFP_KERNEL,
-                                       get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
-       if (!backing_store)
-               goto fail_alloc_signal_store;
-
-       /* Initialize all events to unsignaled */
-       memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
-              KFD_SIGNAL_EVENT_LIMIT * 8);
-
-       page->kernel_address = backing_store;
-       page->need_to_free_pages = true;
-       pr_debug("Allocated new event signal page at %p, for process %p\n",
-                       page, p);
-
-       return page;
-
-fail_alloc_signal_store:
-       kfree(page);
-       return NULL;
-}
-
 static int allocate_event_notification_slot(struct kfd_process *p,
                                            struct kfd_event *ev,
                                            const int *restore_id)
 {
        int id;
 
-       if (!p->signal_page) {
-               p->signal_page = allocate_signal_page(p);
-               if (!p->signal_page)
-                       return -ENOMEM;
-               /* Oldest user mode expects 256 event slots */
-               p->signal_mapped_size = 256*8;
-       }
+       /*
+        * The signal page is allocated in user mode and mapped to the kernel
+        * via the event_page_offset of the create event IOCTL. Without it no
+        * signal events can be created.
+        */
+       if (!p->signal_page)
+               return -ENOMEM;
 
        if (restore_id) {
                id = idr_alloc(&p->event_idr, ev, *restore_id, *restore_id + 1,
@@ -212,10 +180,8 @@ static int create_signal_event(struct file *devkfd, struct kfd_process *p,
 
        p->signal_event_count++;
 
-       ev->user_signal_address = &p->signal_page->user_address[ev->event_id];
-       pr_debug("Signal event number %zu created with id %d, address %p\n",
-                       p->signal_event_count, ev->event_id,
-                       ev->user_signal_address);
+       pr_debug("Signal event number %zu created with id %d\n",
+                       p->signal_event_count, ev->event_id);
 
        return 0;
 }
@@ -303,12 +269,7 @@ static void shutdown_signal_page(struct kfd_process *p)
 {
        struct kfd_signal_page *page = p->signal_page;
 
-       if (page) {
-               if (page->need_to_free_pages)
-                       free_pages((unsigned long)page->kernel_address,
-                                  get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
-               kfree(page);
-       }
+       kfree(page);
 }
 
 void kfd_event_free_process(struct kfd_process *p)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.h b/drivers/gpu/drm/amd/amdkfd/kfd_events.h
index 1dc21c13833b73f094760d3f8812fa1d530cde7a..88e3797bfc4297dcd2f477393c1c33b6c0084a1b 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.h
@@ -63,9 +63,6 @@ struct kfd_event {
        spinlock_t lock;
        wait_queue_head_t wq; /* List of event waiters. */
 
-       /* Only for signal events. */
-       uint64_t __user *user_signal_address;
-
        /* type specific data */
        union {
                struct kfd_hsa_memory_exception_data memory_exception_data;