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Commit 3786bda9 authored by Peter Liu's avatar Peter Liu
Browse files

msm: camera: isp: avoid spin lock recursion on same CPU 



When CPU do spin lock irq save, it will disable irq/preemption.
If the same CPU do spin lock without disabling irq,
then irq context can trigger spin lock irq save
which will hang CPU since the irq/preemption is disabled.

Avoid the issue to use spin lock irq save consistantly.

Change-Id: I38bf80be58744dabf7c2554b50b686b1e304fc4c
Signed-off-by: default avatarPeter Liu <pingchie@codeaurora.org>
parent dfc594f4

drivers/media/platform/msm/camera_v2/isp/msm_buf_mgr.c

+6 −5
Original line number Diff line number Diff line
@@ -209,6 +209,7 @@ static void msm_isp_unprepare_v4l2_buf( 
	struct buffer_cmd *buf_pending = NULL;

	struct msm_isp_bufq *bufq = NULL;

	int iommu_hdl;

	unsigned long flags;



	if (!buf_mgr || !buf_info) {

		pr_err("%s: NULL ptr %p %p\n", __func__,
@@ -234,7 +235,7 @@ static void msm_isp_unprepare_v4l2_buf( 
		cam_smmu_put_phy_addr(iommu_hdl, mapped_info->buf_fd);



		/*protect buffer_q list access*/

		spin_lock(&bufq->bufq_lock);

		spin_lock_irqsave(&bufq->bufq_lock, flags);

		list_for_each_entry(buf_pending, &buf_mgr->buffer_q, list) {

			if (!buf_pending)

				break;
@@ -245,7 +246,7 @@ static void msm_isp_unprepare_v4l2_buf( 
				break;

			}

		}

		spin_unlock(&bufq->bufq_lock);

		spin_unlock_irqrestore(&bufq->bufq_lock, flags);

	}

	return;

}
@@ -806,6 +807,7 @@ static int msm_isp_flush_buf(struct msm_isp_buf_mgr *buf_mgr, 
	int rc = -1, i;

	struct msm_isp_bufq *bufq = NULL;

	struct msm_isp_buffer *buf_info = NULL;

	unsigned long flags;



	bufq = msm_isp_get_bufq(buf_mgr, bufq_handle);

	if (!bufq) {
@@ -813,8 +815,7 @@ static int msm_isp_flush_buf(struct msm_isp_buf_mgr *buf_mgr, 
		return rc;

	}



	spin_lock(&bufq->bufq_lock);



	spin_lock_irqsave(&bufq->bufq_lock, flags);

	for (i = 0; i < bufq->num_bufs; i++) {

		buf_info = msm_isp_get_buf_ptr(buf_mgr, bufq_handle, i);

		if (!buf_info) {
@@ -845,7 +846,7 @@ static int msm_isp_flush_buf(struct msm_isp_buf_mgr *buf_mgr, 
				kfree(buf_info);

		 }

	}

	spin_unlock(&bufq->bufq_lock);

	spin_unlock_irqrestore(&bufq->bufq_lock, flags);

	return 0;

}