On Sat, 27 Jul 2002 16:52:00 -0300 (BRT)
Rik van Riel <riel@conectiva.com.br> wrote:
RVR> On Sat, 27 Jul 2002, Tom Bradley wrote:
RVR>
RVR> > ssize_t my_read(struct file * filp, char * buf, size_t count,
RVR> > loff_t * fpos){
RVR> >
RVR> > ssize_t ret;
RVR> > struct semaphore sem;
RVR>
RVR> Note that I'm not familiar with the semaphore code, so I could be
RVR> wrong ... but won't this effectively give each thread going into
RVR> this code its OWN semaphore on its own stack ?
Indeed.
Tom: As Rik said, in your code each thread has it's own semaphore....so
you'll never have mutual exclusion (with this code). Your threads should
_share_ a "struct semaphore" (correctly initialized [e.g. init_MUTEX],
BTW) so access serialization can be done.
Felipe
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