Re: [PATCH v3 10/10] FIT: add support to cache opened fit images

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Marco,

On 03.07.24 18:58, Marco Felsch wrote:
> Cache the FIT image fit_open() calls to avoid loading the same FIT image
> twice. This is very useful if the same FIT image is used to provide the
> base devicetree, kernel and initrd as well as devicetree overlays.
> 
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
>  common/image-fit.c  | 32 ++++++++++++++++++++++++++++++++
>  include/image-fit.h |  4 ++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/common/image-fit.c b/common/image-fit.c
> index 4839d8dd33a4..a75bb79d1761 100644
> --- a/common/image-fit.c
> +++ b/common/image-fit.c
> @@ -16,6 +16,7 @@
>  #include <fs.h>
>  #include <malloc.h>
>  #include <linux/ctype.h>
> +#include <linux/refcount.h>
>  #include <asm/byteorder.h>
>  #include <errno.h>
>  #include <linux/err.h>
> @@ -32,6 +33,8 @@
>  #define CHECK_LEVEL_SIG 2
>  #define CHECK_LEVEL_MAX 3
>  
> +static LIST_HEAD(open_fits);
> +
>  static uint32_t dt_struct_advance(struct fdt_header *f, uint32_t dt, int size)
>  {
>  	dt += size;
> @@ -847,6 +850,18 @@ void *fit_open_configuration(struct fit_handle *handle, const char *name,
>  	return conf_node;
>  }
>  
> +static struct fit_handle *fit_get_handle(const char *filename)
> +{
> +	struct fit_handle *handle;
> +
> +	list_for_each_entry(handle, &open_fits, entry) {
> +		if (!strcmp(filename, handle->filename))

This wouldn't handle identical relative file names correctly, right?
You'll need to make the filename absolute, I think.

> +			return handle;
> +	}
> +
> +	return NULL;
> +}
> +
>  static int fit_do_open(struct fit_handle *handle)
>  {
>  	const char *desc = "(no description)";
> @@ -896,6 +911,8 @@ struct fit_handle *fit_open_buf(const void *buf, size_t size, bool verbose,
>  	handle->size = size;
>  	handle->verify = verify;
>  
> +	refcount_set(&handle->users, 1);
> +
>  	ret = fit_do_open(handle);
>  	if (ret) {
>  		fit_close(handle);
> @@ -923,6 +940,12 @@ struct fit_handle *fit_open(const char *filename, bool verbose,
>  	struct fit_handle *handle;
>  	int ret;
>  
> +	handle = fit_get_handle(filename);
> +	if (handle) {
> +		refcount_inc(&handle->users);
> +		return handle;
> +	}
> +
>  	handle = xzalloc(sizeof(struct fit_handle));
>  
>  	handle->verbose = verbose;
> @@ -939,6 +962,9 @@ struct fit_handle *fit_open(const char *filename, bool verbose,
>  	handle->fit = handle->fit_alloc;
>  	handle->filename = xstrdup(filename);
>  
> +	refcount_set(&handle->users, 1);
> +	list_add(&handle->entry, &open_fits);
> +
>  	ret = fit_do_open(handle);
>  	if (ret) {
>  		fit_close(handle);
> @@ -950,9 +976,15 @@ struct fit_handle *fit_open(const char *filename, bool verbose,
>  
>  void fit_close(struct fit_handle *handle)
>  {
> +	if (!refcount_dec_and_test(&handle->users))
> +		return;
> +
>  	if (handle->root)
>  		of_delete_node(handle->root);
>  
> +	if (handle->filename)
> +		list_del(&handle->entry);
> +
>  	free(handle->filename);
>  	free(handle->fit_alloc);
>  	free(handle);
> diff --git a/include/image-fit.h b/include/image-fit.h
> index 68f70f4365cb..f9791ff251c5 100644
> --- a/include/image-fit.h
> +++ b/include/image-fit.h
> @@ -7,6 +7,7 @@
>  #define __IMAGE_FIT_H__
>  
>  #include <linux/types.h>
> +#include <linux/refcount.h>
>  #include <bootm.h>
>  
>  struct fit_handle {
> @@ -15,6 +16,9 @@ struct fit_handle {
>  	size_t size;
>  	char *filename;
>  
> +	struct list_head entry;
> +	refcount_t users;
> +
>  	bool verbose;
>  	enum bootm_verify verify;
>  
> 

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