[Public]
To simply code lines, I guess we can drop variable 'r'. And use 'return svm_ioctl(p, args->op.... ' directly.
Regards,
Guchun
-----Original Message-----
From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Philip Yang
Sent: Wednesday, January 26, 2022 2:04 AM
To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Yang, Philip <Philip.Yang@xxxxxxx>; Kuehling, Felix <Felix.Kuehling@xxxxxxx>
Subject: [PATCH 1/1] drm/amdkfd: Don't take process mutex for svm ioctls
SVM ioctls take proper svms->lock to handle race conditions, don't need take process mutex to serialize ioctls. This also fixes circular locking
warning:
WARNING: possible circular locking dependency detected
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((work_completion)(&svms->deferred_list_work));
lock(&process->mutex);
lock((work_completion)(&svms->deferred_list_work));
lock(&process->mutex);
*** DEADLOCK ***
Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
---
drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 337953af7c2f..70122978bdd0 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1846,13 +1846,9 @@ static int kfd_ioctl_svm(struct file *filep, struct kfd_process *p, void *data)
if (!args->start_addr || !args->size)
return -EINVAL;
- mutex_lock(&p->mutex);
-
r = svm_ioctl(p, args->op, args->start_addr, args->size, args->nattr,
args->attrs);
- mutex_unlock(&p->mutex);
-
return r;
}
#else
--
2.17.1
