1. 25 Oct, 2006 5 commits
  2. 05 Oct, 2006 1 commit
    • David Howells's avatar
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      David Howells authored
      
      
      Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
      of passing regs around manually through all ~1800 interrupt handlers in the
      Linux kernel.
      
      The regs pointer is used in few places, but it potentially costs both stack
      space and code to pass it around.  On the FRV arch, removing the regs parameter
      from all the genirq function results in a 20% speed up of the IRQ exit path
      (ie: from leaving timer_interrupt() to leaving do_IRQ()).
      
      Where appropriate, an arch may override the generic storage facility and do
      something different with the variable.  On FRV, for instance, the address is
      maintained in GR28 at all times inside the kernel as part of general exception
      handling.
      
      Having looked over the code, it appears that the parameter may be handed down
      through up to twenty or so layers of functions.  Consider a USB character
      device attached to a USB hub, attached to a USB controller that posts its
      interrupts through a cascaded auxiliary interrupt controller.  A character
      device driver may want to pass regs to the sysrq handler through the input
      layer which adds another few layers of parameter passing.
      
      I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
      main part of the code on FRV and i386, though I can't test most of the drivers.
      I've also done partial conversion for powerpc and MIPS - these at least compile
      with minimal configurations.
      
      This will affect all archs.  Mostly the changes should be relatively easy.
      Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
      
      	struct pt_regs *old_regs = set_irq_regs(regs);
      
      And put the old one back at the end:
      
      	set_irq_regs(old_regs);
      
      Don't pass regs through to generic_handle_irq() or __do_IRQ().
      
      In timer_interrupt(), this sort of change will be necessary:
      
      	-	update_process_times(user_mode(regs));
      	-	profile_tick(CPU_PROFILING, regs);
      	+	update_process_times(user_mode(get_irq_regs()));
      	+	profile_tick(CPU_PROFILING);
      
      I'd like to move update_process_times()'s use of get_irq_regs() into itself,
      except that i386, alone of the archs, uses something other than user_mode().
      
      Some notes on the interrupt handling in the drivers:
      
       (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
           the input_dev struct.
      
       (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
           something different depending on whether it's been supplied with a regs
           pointer or not.
      
       (*) Various IRQ handler function pointers have been moved to type
           irq_handler_t.
      Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
      (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780
  3. 01 Oct, 2006 1 commit
  4. 19 Aug, 2006 1 commit
  5. 09 Jul, 2006 1 commit
  6. 26 Jun, 2006 1 commit
    • Hannes Reinecke's avatar
      [SCSI] aic79xx: remove slave_destroy · f89d0a4e
      Hannes Reinecke authored
      
      
      Even with the latest fixes aic79xx still occasionally triggers the
      BUG_ON in slave_destroy. Rather than trying to figure out the various
      levels of interaction here I've decided to remove the callback altogether.
      
      The primary reason for the slave_alloc / slave_destroy is to keep an
      index of pointers to the sdevs associated with a given target.
      However, by changing the arguments to the affected functions slightly
      it's possible to avoid the use of that index entirely.
      The only performance penalty we'll incur is in writing the
      information for /proc/scsi/XXX, as we'll have to recurse over all
      available sdevs to find the correct ones. But I doubt that reading
      from /proc is in any way time-critical.
      Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
      Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
      f89d0a4e
  7. 10 Jun, 2006 1 commit
  8. 13 Apr, 2006 1 commit
    • Hannes Reinecke's avatar
      [SCSI] aic79xx bus reset update · f41b5cec
      Hannes Reinecke authored
      
      
      As James B. correctly noted, ahd_reset_channel() in
      ahd_linux_bus_reset() should be protected by ahd_lock().  However, the
      main reason for not doing so was a deadlock with the interesting
      polling mechanism to detect the end a bus reset.
      
      This patch replaces the polling mechanism with a saner signalling via
      flags; it also gives us the benefit of detecting any multiple calls to
      ahd_reset_channel().
      Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
      Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
      f41b5cec
  9. 12 Mar, 2006 6 commits
  10. 31 Jan, 2006 2 commits
  11. 12 Jan, 2006 1 commit
  12. 15 Dec, 2005 1 commit
  13. 28 Nov, 2005 1 commit
    • Vasily Averin's avatar
      [SCSI] aic7xxx: reset handler selects a wrong command · dce20067
      Vasily Averin authored
      
      
      To transport scsi reset command to device aic7xxx reset handler looks
      at the driver's pending_list and searches any proper command. However
      the search condition has been inverted: ahc_match_scb() returns TRUE
      if a matched command is found. As a result the reset on required
      devices did not turn out well, a correctly working neighbour device
      may be surprised by the reset. aic7xxx reset handler reports about the
      success, but really the original situation is not corrected yet.
      Signed-off-by: default avatarVasily Averin <vvs@sw.ru>
      
      Naturally, there's a corresponding problem in the aic79xx driver, so
      I've also added the same fix for that.
      Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
      dce20067
  14. 06 Nov, 2005 1 commit
  15. 29 Oct, 2005 2 commits
  16. 02 Oct, 2005 1 commit
  17. 05 Sep, 2005 1 commit
  18. 15 Aug, 2005 1 commit
  19. 09 Aug, 2005 1 commit
  20. 05 Aug, 2005 1 commit
  21. 04 Aug, 2005 1 commit
  22. 03 Aug, 2005 5 commits
  23. 27 Jul, 2005 1 commit
  24. 11 Jul, 2005 1 commit
  25. 20 Jun, 2005 1 commit