cvs commit: src/sys/sys socketvar.h src/sys/kern uipc_sockbuf.c uipc_socket.c uipc_syscalls.c src/sys/netinet sctp_input.c sctp_peeloff.c sctputil.c

[Robert Watson]

rwatson     2008-01-31 08:22:25 UTC

  FreeBSD src repository

  Modified files:
    sys/sys              socketvar.h 
    sys/kern             uipc_sockbuf.c uipc_socket.c 
                         uipc_syscalls.c 
    sys/netinet          sctp_input.c sctp_peeloff.c sctputil.c 
  Log:
  Correct two problems relating to sorflush(), which is called to flush
  read socket buffers in shutdown() and close():
  
  - Call socantrcvmore() before sblock() to dislodge any threads that
    might be sleeping (potentially indefinitely) while holding sblock(),
    such as a thread blocked in recv().
  
  - Flag the sblock() call as non-interruptible so that a signal
    delivered to the thread calling sorflush() doesn't cause sblock() to
    fail.  The sblock() is required to ensure that all other socket
    consumer threads have, in fact, left, and do not enter, the socket
    buffer until we're done flushin it.
  
  To implement the latter, change the 'flags' argument to sblock() to
  accept two flags, SBL_WAIT and SBL_NOINTR, rather than one M_WAITOK
  flag.  When SBL_NOINTR is set, it forces a non-interruptible sx
  acquisition, regardless of the setting of the disposition of SB_NOINTR
  on the socket buffer; without this change it would be possible for
  another thread to clear SB_NOINTR between when the socket buffer mutex
  is released and sblock() is invoked.
  
  Reviewed by:    bz, kmacy
  Reported by:    Jos Backus <jos at catnook dot com>
  
  Revision  Changes    Path
  1.175     +6 -2      src/sys/kern/uipc_sockbuf.c
  1.304     +11 -5     src/sys/kern/uipc_socket.c
  1.264     +7 -2      src/sys/kern/uipc_syscalls.c
  1.67      +2 -1      src/sys/netinet/sctp_input.c
  1.17      +2 -2      src/sys/netinet/sctp_peeloff.c
  1.73      +1 -1      src/sys/netinet/sctputil.c
  1.161     +7 -0      src/sys/sys/socketvar.h