Re: [Qemu-devel] [PATCH] use int64_t for return values from rbd instead of int
On 22 November 2012 08:23, Stefan Priebe - Profihost AG wrote: > Am 21.11.2012 23:32, schrieb Peter Maydell: >> Looking at the librbd API (which is what the size and ret >> values come from), it uses size_t and ssize_t for these. >> So I think probably ssize_t is the right type for ret >> (and size) in our structs here. > > > This sounds reasonable but does ssize_t support negative values? For error > values. Yes, the first 's' in ssize_t means 'signed' and is the difference between it and size_t. -- PMM -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] [PATCH] use int64_t for return values from rbd instead of int
On 21 November 2012 17:03, Stefan Weil wrote: > Why do you use int64_t instead of off_t? > If the value is related to file sizes, off_t would be a good choice. Looking at the librbd API (which is what the size and ret values come from), it uses size_t and ssize_t for these. So I think probably ssize_t is the right type for ret (and size) in our structs here. -- PMM -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] overflow of int ret: use ssize_t for ret
On 23 November 2012 14:11, Stefan Hajnoczi wrote:
> On Thu, Nov 22, 2012 at 10:07 AM, Stefan Priebe wrote:
>> diff --git a/block/rbd.c b/block/rbd.c
>> index 5a0f79f..0384c6c 100644
>> --- a/block/rbd.c
>> +++ b/block/rbd.c
>> @@ -69,7 +69,7 @@ typedef enum {
>> typedef struct RBDAIOCB {
>> BlockDriverAIOCB common;
>> QEMUBH *bh;
>> -int ret;
>> +ssize_t ret;
>> QEMUIOVector *qiov;
>> char *bounce;
>> RBDAIOCmd cmd;
>> @@ -86,7 +86,7 @@ typedef struct RADOSCB {
>> int done;
>> int64_t size;
>> char *buf;
>> -int ret;
>> +ssize_t ret;
>> } RADOSCB;
>>
>> #define RBD_FD_READ 0
>
> I preferred your previous patch:
>
> ssize_t on 32-bit hosts has sizeof(ssize_t) == 4. In
> qemu_rbd_complete_aio() we may assign acb->ret = rcb->size. Here the
> size field is int64_t, so ssize_t ret would truncate the value.
The rcb size field should be a size_t: it is used for calling
rbd_aio_write and rbd_aio_read so if we've overflowed 32 bits
then we've already got a problem there.
-- PMM
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