On 2026-06-11 16:07, Yongqiang Sun wrote:
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 <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_events.c | 59 +++++--------------------
drivers/gpu/drm/amd/amdkfd/kfd_events.h | 3 --
2 files changed, 10 insertions(+), 52 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
index e44f1d1bc516..85e4ad10d619 100644
--- 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;
};
This patch looks good to me. But I think you could even go one step
further, maybe in a third patch. struct kfd_signal_page now has just a
single member. There is really no reason why this structure needs to be
allocated dynamically any more. You could just replace p->signal_page
with a uint64_t * that holds the kernel_address of kmapped the signal BO
directly.
That said, patches 1 and 2 are
Reviewed-by: Felix Kuehling <[email protected]>
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(sizeof(*page), GFP_KERNEL);
- 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 1dc21c13833b..88e3797bfc42 100644
--- 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;
