Re: [PATCH 10/14] HID: i2c-hid: reorder allocation/free of buffers

[Benjamin Tissoires <benjamin.tissoires@gmail.com>]

On Wed, Dec 5, 2012 at 11:10 AM, Jean Delvare <khali@linux-fr.org> wrote:
> On Tue,  4 Dec 2012 16:27:51 +0100, Benjamin Tissoires wrote:
>> Simplifies i2c_hid_alloc_buffers tests, and makes this function
>> responsible of the assignment of ihid->bufsize.
>> The condition for the reallocation in i2c_hid_start is then simpler.
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
>> ---
>>  drivers/hid/i2c-hid/i2c-hid.c | 68 ++++++++++++++++++-------------------------
>>  1 file changed, 28 insertions(+), 40 deletions(-)
>>
>> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
>> index dcacfc4..4e3f80b 100644
>> --- a/drivers/hid/i2c-hid/i2c-hid.c
>> +++ b/drivers/hid/i2c-hid/i2c-hid.c
>> @@ -465,48 +465,38 @@ static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
>>       }
>>  }
>>
>> -static int i2c_hid_alloc_buffers(struct i2c_hid *ihid)
>> +static void i2c_hid_free_buffers(struct i2c_hid *ihid)
>> +{
>> +     kfree(ihid->inbuf);
>> +     kfree(ihid->argsbuf);
>> +     kfree(ihid->cmdbuf);
>> +     ihid->inbuf = NULL;
>> +     ihid->cmdbuf = NULL;
>> +     ihid->argsbuf = NULL;
>> +     ihid->bufsize = 0;
>> +}
>> +
>> +static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
>>  {
>>       /* the worst case is computed from the set_report command with a
>>        * reportID > 15 and the maximum report length */
>>       int args_len = sizeof(__u8) + /* optional ReportID byte */
>>                      sizeof(__u16) + /* data register */
>>                      sizeof(__u16) + /* size of the report */
>> -                    ihid->bufsize; /* report */
>> -
>> -     ihid->inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
>> -
>> -     if (!ihid->inbuf)
>> -             return -ENOMEM;
>> +                    report_size; /* report */
>>
>> +     ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
>>       ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
>> -
>> -     if (!ihid->argsbuf) {
>> -             kfree(ihid->inbuf);
>> -             return -ENOMEM;
>> -     }
>> -
>>       ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
>>
>> -     if (!ihid->cmdbuf) {
>> -             kfree(ihid->inbuf);
>> -             kfree(ihid->argsbuf);
>> -             ihid->inbuf = NULL;
>> -             ihid->argsbuf = NULL;
>> +     if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
>> +             i2c_hid_free_buffers(ihid);
>>               return -ENOMEM;
>>       }
>>
>> -     return 0;
>> -}
>> +     ihid->bufsize = report_size;
>>
>> -static void i2c_hid_free_buffers(struct i2c_hid *ihid)
>> -{
>> -     kfree(ihid->inbuf);
>> -     kfree(ihid->argsbuf);
>> -     kfree(ihid->cmdbuf);
>> -     ihid->inbuf = NULL;
>> -     ihid->cmdbuf = NULL;
>> -     ihid->argsbuf = NULL;
>> +     return 0;
>>  }
>>
>>  static int i2c_hid_get_raw_report(struct hid_device *hid,
>> @@ -611,22 +601,19 @@ static int i2c_hid_start(struct hid_device *hid)
>>       struct i2c_client *client = hid->driver_data;
>>       struct i2c_hid *ihid = i2c_get_clientdata(client);
>>       int ret;
>> -     int old_bufsize = ihid->bufsize;
>> +     unsigned int bufsize = HID_MIN_BUFFER_SIZE;
>>
>> -     ihid->bufsize = HID_MIN_BUFFER_SIZE;
>> -     i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &ihid->bufsize);
>> -     i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &ihid->bufsize);
>> -     i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &ihid->bufsize);
>> +     i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
>> +     i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
>> +     i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
>>
>> -     if (ihid->bufsize > old_bufsize || !ihid->inbuf || !ihid->cmdbuf) {
>> +     if (bufsize > ihid->bufsize) {
>>               i2c_hid_free_buffers(ihid);
>>
>> -             ret = i2c_hid_alloc_buffers(ihid);
>> +             ret = i2c_hid_alloc_buffers(ihid, bufsize);
>>
>> -             if (ret) {
>> -                     ihid->bufsize = old_bufsize;
>> +             if (ret)
>>                       return ret;
>> -             }
>>       }
>>
>>       if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
>> @@ -844,8 +831,9 @@ static int __devinit i2c_hid_probe(struct i2c_client *client,
>>       /* we need to allocate the command buffer without knowing the maximum
>>        * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
>>        * real computation later. */
>> -     ihid->bufsize = HID_MIN_BUFFER_SIZE;
>> -     i2c_hid_alloc_buffers(ihid);
>> +     ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
>> +     if (ret < 0)
>> +             goto err;
>>
>>       ret = i2c_hid_fetch_hid_descriptor(ihid);
>>       if (ret < 0)
>
> Yes, looks much better.
>
> Reviewed-by: Jean Delvare <khali@linux-fr.org>

Thanks Jean,

as mentioned in 2/14, this patch need the fix in 2/14 to be able to
work. Jiri, I'll try to send a v2 ASAP so that you can pick both in
the right order (otherwise, the bisect may fall between the two).

Cheers,
Benjamin

>
> --
> Jean Delvare