Re: [PATCH 2/4] libata: if condition fix for __atapi_pio_bytes()

[Albert Lee <albertcc@tw.ibm.com>]

Hi Bart:

> n 6/10/05, Albert Lee <albertcc@tw.ibm.com> wrote:
> 
>>Hi Jeff,
>>
>>Resend the patch #2 against the linux-2.6.git tree (0086b5ec7834b78358dea3f713275a9ae2b229ec).
>>
>>Problem:
>>    In __atapi_pio_bytes(), when (bytes > qc->nbytes) or (qc->cursg_ofs > sg->length) or
>>(count > bytes), the if condition is not handled properly.
> 
> 
> Only (bytes > qc->nbytes) can happen now.
> 
> 
Yes exactly.

However, could the patch be kept as is?
Maybe I'm worried too much about something that won't happen.
It makes me feel safer using "if (qc->cursg_ofs >= sg->length)" than
using "if (qc->cursg_ofs == sg->length)".
Using ">=" also make it clearer that we don't want to overrun the buffer.

The correct description of the patch is corrected per your advice:

Problem:
    In __atapi_pio_bytes(), when (bytes > qc->nbytes), the if condition is not handled properly.

Changes:
- Fix the "if condition" for the (bytes > qc->nbytes) situation.
- Althought (qc->cursg_ofs > sg->length) and (count > bytes) situation won't happen,
   the "if conditions" are also changed for safty.

Albert