From: Andres Rodriguez <andres.rodriguez@xxxxxxx>
Replace our implementation of a lockless ring buffer with the standard
linux kernel kfifo.
We shouldn't maintain our own version of a standard data structure.
Signed-off-by: Andres Rodriguez <andres.rodriguez at amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 78 ++++++++++--------------------
drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 6 +--
2 files changed, 27 insertions(+), 57 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
index 70b3a99c..ffbb91a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
@@ -42,25 +42,24 @@
#include <linux/slab.h>
#include <linux/device.h>
+#include <linux/kfifo.h>
#include "kfd_priv.h"
-#define KFD_INTERRUPT_RING_SIZE 1024
+#define KFD_IH_NUM_ENTRIES 1024
static void interrupt_wq(struct work_struct *);
int kfd_interrupt_init(struct kfd_dev *kfd)
{
- void *interrupt_ring = kmalloc_array(KFD_INTERRUPT_RING_SIZE,
- kfd->device_info->ih_ring_entry_size,
- GFP_KERNEL);
- if (!interrupt_ring)
- return -ENOMEM;
-
- kfd->interrupt_ring = interrupt_ring;
- kfd->interrupt_ring_size =
- KFD_INTERRUPT_RING_SIZE * kfd->device_info->ih_ring_entry_size;
- atomic_set(&kfd->interrupt_ring_wptr, 0);
- atomic_set(&kfd->interrupt_ring_rptr, 0);
+ int r;
+
+ r = kfifo_alloc(&kfd->ih_fifo,
+ KFD_IH_NUM_ENTRIES * kfd->device_info->ih_ring_entry_size,
+ GFP_KERNEL);
+ if (r) {
+ dev_err(kfd_chardev(), "Failed to allocate IH fifo\n");
+ return r;
+ }
spin_lock_init(&kfd->interrupt_lock);
@@ -98,68 +97,41 @@ void kfd_interrupt_exit(struct kfd_dev *kfd)
*/
flush_scheduled_work();
- kfree(kfd->interrupt_ring);
+ kfifo_free(&kfd->ih_fifo);
}
/*
- * This assumes that it can't be called concurrently with itself
- * but only with dequeue_ih_ring_entry.
+ * Assumption: single reader/writer. This function is not re-entrant
*/
bool enqueue_ih_ring_entry(struct kfd_dev *kfd, const void *ih_ring_entry)
{
- unsigned int rptr = atomic_read(&kfd->interrupt_ring_rptr);
- unsigned int wptr = atomic_read(&kfd->interrupt_ring_wptr);
+ int count;
- if ((rptr - wptr) % kfd->interrupt_ring_size ==
- kfd->device_info->ih_ring_entry_size) {
- /* This is very bad, the system is likely to hang. */
+ count = kfifo_in(&kfd->ih_fifo, ih_ring_entry,
+ kfd->device_info->ih_ring_entry_size);
+ if (count != kfd->device_info->ih_ring_entry_size) {
dev_err_ratelimited(kfd_chardev(),
- "Interrupt ring overflow, dropping interrupt.\n");
+ "Interrupt ring overflow, dropping interrupt %d\n",
+ count);
return false;
}
- memcpy(kfd->interrupt_ring + wptr, ih_ring_entry,
- kfd->device_info->ih_ring_entry_size);
-
- wptr = (wptr + kfd->device_info->ih_ring_entry_size) %
- kfd->interrupt_ring_size;
- smp_wmb(); /* Ensure memcpy'd data is visible before wptr update. */
- atomic_set(&kfd->interrupt_ring_wptr, wptr);
-
return true;
}
/*
- * This assumes that it can't be called concurrently with itself
- * but only with enqueue_ih_ring_entry.
+ * Assumption: single reader/writer. This function is not re-entrant
*/
static bool dequeue_ih_ring_entry(struct kfd_dev *kfd, void *ih_ring_entry)
{
- /*
- * Assume that wait queues have an implicit barrier, i.e. anything that
- * happened in the ISR before it queued work is visible.
- */
-
- unsigned int wptr = atomic_read(&kfd->interrupt_ring_wptr);
- unsigned int rptr = atomic_read(&kfd->interrupt_ring_rptr);
+ int count;
- if (rptr == wptr)
- return false;
-
- memcpy(ih_ring_entry, kfd->interrupt_ring + rptr,
- kfd->device_info->ih_ring_entry_size);
-
- rptr = (rptr + kfd->device_info->ih_ring_entry_size) %
- kfd->interrupt_ring_size;
+ count = kfifo_out(&kfd->ih_fifo, ih_ring_entry,
+ kfd->device_info->ih_ring_entry_size);
- /*
- * Ensure the rptr write update is not visible until
- * memcpy has finished reading.
- */
- smp_mb();
- atomic_set(&kfd->interrupt_ring_rptr, rptr);
+ WARN_ON(count && count != kfd->device_info->ih_ring_entry_size);
- return true;
+ return count == kfd->device_info->ih_ring_entry_size;
}
static void interrupt_wq(struct work_struct *work)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index ebae8e1..e8d6c0e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -32,6 +32,7 @@
#include <linux/spinlock.h>
#include <linux/kfd_ioctl.h>
#include <linux/idr.h>
+#include <linux/kfifo.h>
#include <kgd_kfd_interface.h>
#include "amd_shared.h"
@@ -182,10 +183,7 @@ struct kfd_dev {
unsigned int gtt_sa_num_of_chunks;
/* Interrupts */
- void *interrupt_ring;
- size_t interrupt_ring_size;
- atomic_t interrupt_ring_rptr;
- atomic_t interrupt_ring_wptr;
+ struct kfifo ih_fifo;
struct work_struct interrupt_work;
spinlock_t interrupt_lock;
--
2.7.4
