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Subject[RFC PATCH 3/4] rpmsg: apu_rpmsg: update the way to store IOMMU mapping
Date
In order to reduce the memory mapping operations we are going to
add an IOCTL to request a mapping.
To make easier to add this new operation, use 2 lists to store the
mappings, one for the request and one for the device.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
---
drivers/rpmsg/apu_rpmsg.c | 104 +++++++++++++++++++++++++-------------
1 file changed, 70 insertions(+), 34 deletions(-)

diff --git a/drivers/rpmsg/apu_rpmsg.c b/drivers/rpmsg/apu_rpmsg.c
index e14597c467d7..343bd08a859a 100644
--- a/drivers/rpmsg/apu_rpmsg.c
+++ b/drivers/rpmsg/apu_rpmsg.c
@@ -38,12 +38,14 @@ struct rpmsg_apu {
u8 available_response;
spinlock_t ctx_lock;
struct list_head requests;
+
+ struct list_head buffers;
};

struct rpmsg_request {
u8 ready;
struct list_head node;
- struct apu_buffer *buffer;
+ struct list_head buffers;
void *req;
};

@@ -53,6 +55,11 @@ struct apu_buffer {
struct dma_buf_attachment *attachment;
struct sg_table *sg_table;
u32 iova;
+
+ struct rpmsg_apu *apu;
+ struct list_head node;
+ struct list_head req_node;
+ struct kref refcount;
};

/*
@@ -106,23 +113,46 @@ static int apu_rpmsg_callback(struct rpmsg_device *rpdev, void *data, int count,
return 0;
}

-static int apu_device_memory_map(struct rpmsg_apu *apu,
- struct apu_buffer *buffer)
+static struct apu_buffer *apu_device_memory_map(struct rpmsg_apu *apu,
+ uint32_t fd, struct rpmsg_request *rpmsg_req)
{
struct rpmsg_device *rpdev = apu->rpdev;
+ struct apu_buffer *buffer;
phys_addr_t phys;
int total_buf_space;
int iova_pfn;
int ret;

- if (!buffer->fd)
- return 0;
+ if (!fd)
+ return NULL;
+
+ list_for_each_entry(buffer, &apu->buffers, node) {
+ if (buffer->fd == fd) {
+ kref_get(&buffer->refcount);
+ if (rpmsg_req)
+ list_add(&buffer->req_node,
+ &rpmsg_req->buffers);
+
+ return buffer;
+ }
+ }
+
+ buffer = kmalloc(sizeof(*buffer), GFP_KERNEL);
+ if (!buffer)
+ return ERR_PTR(-ENOMEM);
+
+ kref_init(&buffer->refcount);
+ buffer->fd = fd;
+ buffer->apu = apu;
+ INIT_LIST_HEAD(&buffer->req_node);
+ INIT_LIST_HEAD(&buffer->node);

buffer->dma_buf = dma_buf_get(buffer->fd);
if (IS_ERR(buffer->dma_buf)) {
dev_err(&rpdev->dev, "Failed to get dma_buf from fd: %ld\n",
PTR_ERR(buffer->dma_buf));
- return PTR_ERR(buffer->dma_buf);
+ ret = PTR_ERR(buffer->dma_buf);
+ goto err_free_buffer;
}

buffer->attachment = dma_buf_attach(buffer->dma_buf, &rpdev->dev);
@@ -158,7 +188,9 @@ static int apu_device_memory_map(struct rpmsg_apu *apu,
goto err_free_iova;
}

- return 0;
+ list_add(&buffer->node, &apu->buffers);
+
+ return buffer;

err_free_iova:
free_iova(apu->iovad, iova_pfn);
@@ -170,13 +202,17 @@ static int apu_device_memory_map(struct rpmsg_apu *apu,
dma_buf_detach(buffer->dma_buf, buffer->attachment);
err_dma_buf_put:
dma_buf_put(buffer->dma_buf);
+err_free_buffer:
+ kfree(buffer);

- return ret;
+ return ERR_PTR(ret);
}

-static void apu_device_memory_unmap(struct rpmsg_apu *apu,
- struct apu_buffer *buffer)
+static void apu_device_memory_unmap(struct kref *ref)
{
+ struct apu_buffer *buffer = container_of(ref, struct apu_buffer,
+ refcount);
+ struct rpmsg_apu *apu = buffer->apu;
int total_buf_space;

if (!buffer->fd)
@@ -190,6 +226,8 @@ static void apu_device_memory_unmap(struct rpmsg_apu *apu,
DMA_BIDIRECTIONAL);
dma_buf_detach(buffer->dma_buf, buffer->attachment);
dma_buf_put(buffer->dma_buf);
+ list_del(&buffer->node);
+ kfree(buffer);
}

static int apu_send_request(struct rpmsg_apu *apu,
@@ -198,7 +236,7 @@ static int apu_send_request(struct rpmsg_apu *apu,
int ret;
struct rpmsg_device *rpdev = apu->rpdev;
struct apu_dev_request *dev_req;
- struct apu_buffer *buffer;
+ struct apu_buffer *buffer, *tmp;
struct rpmsg_request *rpmsg_req;
unsigned long flags;

@@ -222,14 +260,21 @@ static int apu_send_request(struct rpmsg_apu *apu,
dev_req_buffer_size = (u32 *)(dev_req_da + dev_req->count);
memcpy(dev_req->data, req->data, req->size_in);

- buffer = kmalloc_array(req->count, sizeof(*buffer), GFP_KERNEL);
+ rpmsg_req = kzalloc(sizeof(*rpmsg_req), GFP_KERNEL);
+ if (!rpmsg_req)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&rpmsg_req->buffers);
for (i = 0; i < req->count; i++) {
- buffer[i].fd = fd[i];
- ret = apu_device_memory_map(apu, &buffer[i]);
- if (ret)
+ buffer = apu_device_memory_map(apu, fd[i], rpmsg_req);
+ if (IS_ERR(buffer)) {
+ ret = PTR_ERR(buffer);
goto err_free_memory;
- dev_req_da[i] = buffer[i].iova;
+ }
+
+ dev_req_da[i] = buffer->iova;
dev_req_buffer_size[i] = buffer_size[i];
+ list_add(&buffer->req_node, &rpmsg_req->buffers);
}

ret = ida_simple_get(&req_ida, 0, 0xffff, GFP_KERNEL);
@@ -238,15 +283,8 @@ static int apu_send_request(struct rpmsg_apu *apu,

dev_req->id = ret;

- rpmsg_req = kzalloc(sizeof(*rpmsg_req), GFP_KERNEL);
- if (!rpmsg_req) {
- ret = -ENOMEM;
- goto err_ida_remove;
- }
-
req->id = dev_req->id;
rpmsg_req->req = req;
- rpmsg_req->buffer = buffer;
spin_lock_irqsave(&apu->ctx_lock, flags);
list_add(&rpmsg_req->node, &apu->requests);
spin_unlock_irqrestore(&apu->ctx_lock, flags);
@@ -261,15 +299,12 @@ static int apu_send_request(struct rpmsg_apu *apu,

err:
list_del(&rpmsg_req->node);
- kfree(rpmsg_req);
kfree(req);
-err_ida_remove:
ida_simple_remove(&req_ida, dev_req->id);
err_free_memory:
- for (i--; i >= 0; i--)
- apu_device_memory_unmap(apu, &buffer[i]);
-
- kfree(buffer);
+ list_for_each_entry_safe(buffer, tmp, &rpmsg_req->buffers, req_node)
+ kref_put(&buffer->refcount, apu_device_memory_unmap);
+ kfree(rpmsg_req);
kfree(dev_req);

return ret;
@@ -296,12 +331,12 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
struct rpmsg_apu *apu = fp->private_data;
struct apu_request apu_req;
struct apu_request *apu_req_full;
+ struct apu_buffer *buffer, *tmp;
void __user *argp = (void __user *)arg;
int len;
int ret;
unsigned long flags;
struct rpmsg_request *rpmsg_req;
- int i;

ret = 0;

@@ -370,11 +405,11 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
ret = -EFAULT;
apu->available_response--;
ida_simple_remove(&req_ida, req->id);
- for (i = 0; i < req->count ; i++)
- apu_device_memory_unmap(apu,
- &rpmsg_req->buffer[i]);
+ list_for_each_entry_safe(buffer, tmp, &rpmsg_req->buffers, req_node) {
+ kref_put(&buffer->refcount, apu_device_memory_unmap);
+ list_del(&buffer->req_node);
+ }
list_del(&rpmsg_req->node);
- kfree(rpmsg_req->buffer);
kfree(rpmsg_req->req);
kfree(rpmsg_req);
break;
@@ -554,6 +589,7 @@ static int apu_rpmsg_probe(struct rpmsg_device *rpdev)
if (!apu)
return -ENOMEM;
apu->rpdev = rpdev;
+ INIT_LIST_HEAD(&apu->buffers);

apu->rproc = apu_get_rproc(rpdev);
if (IS_ERR_OR_NULL(apu->rproc))
--
2.26.2
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