dma_buf_set_name() originally took a __user string to duplicate for the buffer name. Make this function a generic set-name helper, taking a kernel-allocated string.
Wrap this by a new dma_buf_set_name_user() to support the existing ioctl path for a user-provided string. Signed-off-by: Matt Evans <[email protected]> --- drivers/dma-buf/dma-buf.c | 58 ++++++++++++++++++++++++++++++--------- include/linux/dma-buf.h | 2 ++ 2 files changed, 47 insertions(+), 13 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index d504c636dc29..8129ea11ff58 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -405,31 +405,29 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) } /** - * dma_buf_set_name - Set a name to a specific dma_buf to track the usage. - * It could support changing the name of the dma-buf if the same - * piece of memory is used for multiple purpose between different devices. + * dma_buf_set_name_user - Set a dma_buf's name from a user string + * + * The string is up to DMA_BUF_NAME_LEN long, including the terminator. * * @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. - * + * Returns 0 on success, and any previously-set name is freed. */ -static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) +static long dma_buf_set_name_user(struct dma_buf *dmabuf, const char __user *buf) { char *name = strndup_user(buf, DMA_BUF_NAME_LEN); + int ret; if (IS_ERR(name)) return PTR_ERR(name); - spin_lock(&dmabuf->name_lock); - kfree(dmabuf->name); - dmabuf->name = name; - spin_unlock(&dmabuf->name_lock); + ret = dma_buf_set_name(dmabuf, name); + if (ret) + kfree(name); - return 0; + return ret; } #if IS_ENABLED(CONFIG_SYNC_FILE) @@ -578,7 +576,7 @@ static long dma_buf_ioctl(struct file *file, case DMA_BUF_SET_NAME_A: case DMA_BUF_SET_NAME_B: - return dma_buf_set_name(dmabuf, (const char __user *)arg); + return dma_buf_set_name_user(dmabuf, (const char __user *)arg); #if IS_ENABLED(CONFIG_SYNC_FILE) case DMA_BUF_IOCTL_EXPORT_SYNC_FILE: @@ -854,6 +852,40 @@ void dma_buf_put(struct dma_buf *dmabuf) } EXPORT_SYMBOL_NS_GPL(dma_buf_put, "DMA_BUF"); +/** + * dma_buf_set_name - Set a dma_buf's name + * It could 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. + * @name: [in] The name of the dma-buf, allocated with kmalloc() or + * similar. This takes ownership of the allocation + * on success, which will be kfree()d when the + * dmabuf is released or a new name assigned. + * + * Returns 0 on success, -EINVAL if the name is NULL, or -E2BIG if the + * name exceeds DMA_BUF_NAME_LEN. + */ +int dma_buf_set_name(struct dma_buf *dmabuf, char *name) +{ + if (!name) + return -EINVAL; + + /* dmabuffs_dname() won't use the string if the length + * (including terminator) exceeds DMA_BUF_NAME_LEN: + */ + if (strlen(name) >= DMA_BUF_NAME_LEN) + return -E2BIG; + + spin_lock(&dmabuf->name_lock); + kfree(dmabuf->name); + dmabuf->name = name; + spin_unlock(&dmabuf->name_lock); + + return 0; +} +EXPORT_SYMBOL_NS_GPL(dma_buf_set_name, "DMA_BUF"); + static int dma_buf_wrap_sg_table(struct sg_table **sg_table) { struct scatterlist *to_sg, *from_sg; diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index d1203da56fc5..14d3950b63c8 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -570,6 +570,8 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags); struct dma_buf *dma_buf_get(int fd); void dma_buf_put(struct dma_buf *dmabuf); +int dma_buf_set_name(struct dma_buf *dmabuf, char *name); + struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *, enum dma_data_direction); void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, -- 2.50.1 (Apple Git-155)
