[lwip-devel] [bug #19573] netconn_delete treats 1ms wait as poll

[Jonathan Larmour]

URL:
  <http://savannah.nongnu.org/bugs/?19573>

                 Summary: netconn_delete treats 1ms wait as poll
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: jifl
            Submitted on: Wednesday 04/11/2007 at 04:17
                Category: None
                Severity: 2 - Minor
              Item Group: Change Request
                  Status: Need Info
                 Privacy: Public
             Assigned to: jifl
             Open/Closed: Open
         Discussion Lock: Any

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Details:

I raised an issue in bug #19161 that various places in api_lib.c used 1ms
waits as if they were polls. In that bug I said I was wrong, but actually I
wasn't: netconn_delete does this twice, while trying to purge the recvmbox
and acceptmbox.

So I think we do need some form of new sys abstraction to allow a polled wait
on an mbox that returns right away if it is not available.

I suggest something along the lines of this in sys.h:

/* sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate */
#define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT

#if SYS_HAS_MBOX_TRYFETCH
extern u32_t sys_arch_mbox_tryfetch(sys_mbox_t mbox, void **msg);
#define sys_mbox_tryfetch(_mb,_m) \
  sys_arch_mbox_tryfetch((_mb),(_m))
#else
#define sys_mbox_tryfetch(_mb,_m) \
  sys_arch_mbox_fetch((_mb),(_m), 1)
#endif

with a corresponding #define in opt.h for SYS_HAS_MBOX_TRYFETCH. Initially
this will default to 0 to preserve existing behaviour for ports. Perhaps in a
while it can default to 1.

But I know there's a lot going on in this area, so I want to know if anyone
had any other plans for this function before I do something.




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