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authorGreg Hackmann <ghackmann@google.com>2019-06-14 01:34:07 +0300
committerSumit Semwal <sumit.semwal@linaro.org>2019-06-14 12:30:51 +0300
commitbb2bb903042517b8fb17b2bc21e00512f2dcac01 (patch)
treecae5b81f60ea2d1ceefd2e2d3bfe3fd4e8aa63da /drivers/dma-buf
parented63bb1d1f8469586006a9ca63c42344401aa2ab (diff)
downloadlinux-bb2bb903042517b8fb17b2bc21e00512f2dcac01.tar.xz
dma-buf: add DMA_BUF_SET_NAME ioctls
This patch adds complimentary DMA_BUF_SET_NAME ioctls, which lets userspace processes attach a free-form name to each buffer. This information can be extremely helpful for tracking and accounting shared buffers. For example, on Android, we know what each buffer will be used for at allocation time: GL, multimedia, camera, etc. The userspace allocator can use DMA_BUF_SET_NAME to associate that information with the buffer, so we can later give developers a breakdown of how much memory they're allocating for graphics, camera, etc. Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190613223408.139221-3-fengc@google.com
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-buf.c65
1 files changed, 62 insertions, 3 deletions
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 3612ccededd6..ab96410d1dcd 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -48,8 +48,24 @@ struct dma_buf_list {
static struct dma_buf_list db_list;
+static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+ struct dma_buf *dmabuf;
+ char name[DMA_BUF_NAME_LEN];
+ size_t ret = 0;
+
+ dmabuf = dentry->d_fsdata;
+ mutex_lock(&dmabuf->lock);
+ if (dmabuf->name)
+ ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN);
+ mutex_unlock(&dmabuf->lock);
+
+ return dynamic_dname(dentry, buffer, buflen, "/%s:%s",
+ dentry->d_name.name, ret > 0 ? name : "");
+}
+
static const struct dentry_operations dma_buf_dentry_ops = {
- .d_dname = simple_dname,
+ .d_dname = dmabuffs_dname,
};
static struct vfsmount *dma_buf_mnt;
@@ -301,6 +317,43 @@ out:
return events;
}
+/**
+ * dma_buf_set_name - Set a name to a specific dma_buf to track the usage.
+ * The name of the dma-buf buffer can only be set when the dma-buf is not
+ * attached to any devices. It could theoritically support changing the
+ * name of the dma-buf if the same piece of memory is used for multiple
+ * purpose between different devices.
+ *
+ * @dmabuf [in] dmabuf buffer that will be renamed.
+ * @buf: [in] A piece of userspace memory that contains the name of
+ * the dma-buf.
+ *
+ * Returns 0 on success. If the dma-buf buffer is already attached to
+ * devices, return -EBUSY.
+ *
+ */
+static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
+{
+ char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
+ long ret = 0;
+
+ if (IS_ERR(name))
+ return PTR_ERR(name);
+
+ mutex_lock(&dmabuf->lock);
+ if (!list_empty(&dmabuf->attachments)) {
+ ret = -EBUSY;
+ kfree(name);
+ goto out_unlock;
+ }
+ kfree(dmabuf->name);
+ dmabuf->name = name;
+
+out_unlock:
+ mutex_unlock(&dmabuf->lock);
+ return ret;
+}
+
static long dma_buf_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
@@ -339,6 +392,10 @@ static long dma_buf_ioctl(struct file *file,
ret = dma_buf_begin_cpu_access(dmabuf, direction);
return ret;
+
+ case DMA_BUF_SET_NAME:
+ return dma_buf_set_name(dmabuf, (const char __user *)arg);
+
default:
return -ENOTTY;
}
@@ -380,6 +437,7 @@ static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags)
goto err_alloc_file;
file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
file->private_data = dmabuf;
+ file->f_path.dentry->d_fsdata = dmabuf;
return file;
@@ -1112,12 +1170,13 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
continue;
}
- seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\n",
+ seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
buf_obj->size,
buf_obj->file->f_flags, buf_obj->file->f_mode,
file_count(buf_obj->file),
buf_obj->exp_name,
- file_inode(buf_obj->file)->i_ino);
+ file_inode(buf_obj->file)->i_ino,
+ buf_obj->name ?: "");
robj = buf_obj->resv;
while (true) {