Re: [Qemu-devel] [PATCH 1/2 v2] usb-mtp: Reallocate buffer in multiples of MTP_WRITE_BUF_SZ

[Bandan Das <bsd@redhat.com>]

Eric Blake <eblake@redhat.com> writes:

> On 1/11/19 2:20 AM, Bandan Das wrote:
>> This is a "pre-patch" to breaking up the write buffer for
>> MTP writes. Instead of allocating a mtp buffer equal to size
>> sent by the initiator, we start with a small size and reallocate
>> multiples (of that small size) as needed.
>> 
>> Signed-off-by: Bandan Das <bsd@redhat.com>
>> ---
>>  hw/usb/dev-mtp.c | 26 ++++++++++++--------------
>>  1 file changed, 12 insertions(+), 14 deletions(-)
>> 
>> diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
>> index b19b576278..a0d98c93ee 100644
>> --- a/hw/usb/dev-mtp.c
>> +++ b/hw/usb/dev-mtp.c
>> @@ -152,7 +152,6 @@ struct MTPData {
>>      bool         first;
>>      /* Used for >4G file sizes */
>>      bool         pending;
>> -    uint64_t     cached_length;
>>      int          fd;
>>  };
>>  
>> @@ -244,6 +243,7 @@ typedef struct {
>>  
>>  #define MTP_MANUFACTURER  "QEMU"
>>  #define MTP_PRODUCT       "QEMU filesharing"
>> +#define MTP_WRITE_BUF_SZ  512000
>
> Why not a power of two?  Perhaps use units.h and spell it (512 * KiB) ?

Sure, I will change it in a later patch.

Bandan