openwrt/target/linux/brcm2708/patches-4.19/950-0696-Revert-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-bu.patch

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From 41079f8602ae082b78e33e7d326ff5f57b7d76e8 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.org>
Date: Fri, 28 Jun 2019 11:30:49 +0100
Subject: [PATCH 696/703] Revert "media: vb2: Allow reqbufs(0) with "in use"
MMAP buffers"
This reverts commit a2c73e18c1f657de6d654f51effa0a94863abbd8.
An alternative version was accepted upstream. Revert this patch to
apply that one.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
---
.../media/common/videobuf2/videobuf2-core.c | 23 +++++++++++++++++++
1 file changed, 23 insertions(+)
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -550,6 +550,20 @@ bool vb2_buffer_in_use(struct vb2_queue
}
EXPORT_SYMBOL(vb2_buffer_in_use);
+/*
+ * __buffers_in_use() - return true if any buffers on the queue are in use and
+ * the queue cannot be freed (by the means of REQBUFS(0)) call
+ */
+static bool __buffers_in_use(struct vb2_queue *q)
+{
+ unsigned int buffer;
+ for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+ if (vb2_buffer_in_use(q, q->bufs[buffer]))
+ return true;
+ }
+ return false;
+}
+
void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
{
call_void_bufop(q, fill_user_buffer, q->bufs[index], pb);
@@ -661,7 +675,16 @@ int vb2_core_reqbufs(struct vb2_queue *q
if (*count == 0 || q->num_buffers != 0 ||
(q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory)) {
+ /*
+ * We already have buffers allocated, so first check if they
+ * are not in use and can be freed.
+ */
mutex_lock(&q->mmap_lock);
+ if (q->memory == VB2_MEMORY_MMAP && __buffers_in_use(q)) {
+ mutex_unlock(&q->mmap_lock);
+ dprintk(1, "memory in use, cannot free\n");
+ return -EBUSY;
+ }
/*
* Call queue_cancel to clean up any buffers in the PREPARED or