>
> On 12/10/23 03:27, Dinghao Liu wrote:
> > Use the scope based resource management (defined in
> > linux/cleanup.h) to automate resource lifetime
> > control on struct btt_sb *super in discover_arenas().
> >
> > Signed-off-by: Dinghao Liu <dinghao....@zju.edu.cn>
> > ---
> > drivers/nvdimm/btt.c | 12 ++++--------
> > 1 file changed, 4 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> > index d5593b0dc700..ff42778b51de 100644
> > --- a/drivers/nvdimm/btt.c
> > +++ b/drivers/nvdimm/btt.c
> > @@ -16,6 +16,7 @@
> > #include <linux/fs.h>
> > #include <linux/nd.h>
> > #include <linux/backing-dev.h>
> > +#include <linux/cleanup.h>
> > #include "btt.h"
> > #include "nd.h"
> >
> > @@ -847,7 +848,7 @@ static int discover_arenas(struct btt *btt)
> > {
> > int ret = 0;
> > struct arena_info *arena;
> > - struct btt_sb *super;
> > + struct btt_sb *super __free(kfree) = NULL;
> > size_t remaining = btt->rawsize;
> > u64 cur_nlba = 0;
> > size_t cur_off = 0;
> > @@ -860,10 +861,8 @@ static int discover_arenas(struct btt *btt)
> > while (remaining) {
> > /* Alloc memory for arena */
> > arena = alloc_arena(btt, 0, 0, 0);
> > - if (!arena) {
> > - ret = -ENOMEM;
> > - goto out_super;
> > - }
> > + if (!arena)
> > + return -ENOMEM;
> >
> > arena->infooff = cur_off;
> > ret = btt_info_read(arena, super);
> > @@ -919,14 +918,11 @@ static int discover_arenas(struct btt *btt)
> > btt->nlba = cur_nlba;
> > btt->init_state = INIT_READY;
> >
> > - kfree(super);
> > return ret;
> >
> > out:
> > kfree(arena);
> > free_arenas(btt);
> > - out_super:
> > - kfree(super);
> > return ret;
> > }
> >
>
> I would do the allocation like something below for the first chunk. Otherwise
> the rest LGTM.
>
> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> index d5593b0dc700..143921e7f26c 100644
> --- a/drivers/nvdimm/btt.c
> +++ b/drivers/nvdimm/btt.c
> @@ -16,6 +16,7 @@
> #include <linux/fs.h>
> #include <linux/nd.h>
> #include <linux/backing-dev.h>
> +#include <linux/cleanup.h>
> #include "btt.h"
> #include "nd.h"
>
> @@ -845,25 +846,23 @@ static void parse_arena_meta(struct arena_info *arena,
> struct btt_sb *super,
>
> static int discover_arenas(struct btt *btt)
> {
> + struct btt_sb *super __free(kfree) =
> + kzalloc(sizeof(*super), GFP_KERNEL);
> int ret = 0;
> struct arena_info *arena;
> - struct btt_sb *super;
> size_t remaining = btt->rawsize;
> u64 cur_nlba = 0;
> size_t cur_off = 0;
> int num_arenas = 0;
>
> - super = kzalloc(sizeof(*super), GFP_KERNEL);
> if (!super)
> return -ENOMEM;
>
> while (remaining) {
> /* Alloc memory for arena */
It's a little strange that we do not check super immediately after allocation.
How about this:
static int discover_arenas(struct btt *btt)
{
int ret = 0;
struct arena_info *arena;
- struct btt_sb *super;
size_t remaining = btt->rawsize;
u64 cur_nlba = 0;
size_t cur_off = 0;
int num_arenas = 0;
- super = kzalloc(sizeof(*super), GFP_KERNEL);
+ struct btt_sb *super __free(kfree) =
+ kzalloc(sizeof(*super), GFP_KERNEL);
if (!super)
return -ENOMEM;
while (remaining) {
