On 12/12/23 20:12, dinghao....@zju.edu.cn wrote:
>>
>> 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) {
>
That's fine by me
