1. 11 Feb, 2007 1 commit
  2. 30 Dec, 2006 1 commit
  3. 08 Dec, 2006 4 commits
  4. 22 Nov, 2006 1 commit
  5. 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
  6. 02 Oct, 2006 1 commit
    • Jeff Dike's avatar
      [PATCH] const struct tty_operations · b68e31d0
      Jeff Dike authored
      As part of an SMP cleanliness pass over UML, I consted a bunch of
      structures in order to not have to document their locking.  One of these
      structures was a struct tty_operations.  In order to const it in UML
      without introducing compiler complaints, the declaration of
      tty_set_operations needs to be changed, and then all of its callers need to
      be fixed.
      
      This patch declares all struct tty_operations in the tree as const.  In all
      cases, they are static and used only as input to tty_set_operations.  As an
      extra check, I ran an i386 allyesconfig build which produced no extra
      warnings.
      
      53 drivers are affected.  I checked the history of a bunch of them, and in
      most cases, there have been only a handful of maintenance changes in the
      last six months.  serial_core.c was the busiest one that I looked at.
      Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
      Acked-by: default avatarAlan Cox <alan@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      b68e31d0
  7. 01 Oct, 2006 1 commit
  8. 02 Jul, 2006 1 commit
  9. 30 Jun, 2006 1 commit
  10. 28 Jun, 2006 1 commit
    • Paul Fulghum's avatar
      [PATCH] remove TTY_DONT_FLIP · 817d6d3b
      Paul Fulghum authored
      Remove TTY_DONT_FLIP tty flag.  This flag was introduced in 2.1.X kernels
      to prevent the N_TTY line discipline functions read_chan() and
      n_tty_receive_buf() from running at the same time.  2.2.15 introduced
      tty->read_lock to protect access to the N_TTY read buffer, which is the
      only state requiring protection between these two functions.
      
      The current TTY_DONT_FLIP implementation is broken for SMP, and is not
      universally honored by drivers that send data directly to the line
      discipline receive_buf function.
      
      Because TTY_DONT_FLIP is not necessary, is broken in implementation, and is
      not universally honored, it is removed.
      Signed-off-by: default avatarPaul Fulghum <paulkf@microgate.com>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      817d6d3b
  11. 25 Jun, 2006 3 commits
  12. 25 Mar, 2006 1 commit
  13. 10 Jan, 2006 2 commits
    • Alan Cox's avatar
      [PATCH] TTY layer buffering revamp · 33f0f88f
      Alan Cox authored
      The API and code have been through various bits of initial review by
      serial driver people but they definitely need to live somewhere for a
      while so the unconverted drivers can get knocked into shape, existing
      drivers that have been updated can be better tuned and bugs whacked out.
      
      This replaces the tty flip buffers with kmalloc objects in rings. In the
      normal situation for an IRQ driven serial port at typical speeds the
      behaviour is pretty much the same, two buffers end up allocated and the
      kernel cycles between them as before.
      
      When there are delays or at high speed we now behave far better as the
      buffer pool can grow a bit rather than lose characters. This also means
      that we can operate at higher speeds reliably.
      
      For drivers that receive characters in blocks (DMA based, USB and
      especially virtualisation) the layer allows a lot of driver specific
      code that works around the tty layer with private secondary queues to be
      removed. The IBM folks need this sort of layer, the smart serial port
      people do, the virtualisers do (because a virtualised tty typically
      operates at infinite speed rather than emulating 9600 baud).
      
      Finally many drivers had invalid and unsafe attempts to avoid buffer
      overflows by directly invoking tty methods extracted out of the innards
      of work queue structs. These are no longer needed and all go away. That
      fixes various random hangs with serial ports on overflow.
      
      The other change in here is to optimise the receive_room path that is
      used by some callers. It turns out that only one ldisc uses receive room
      except asa constant and it updates it far far less than the value is
      read. We thus make it a variable not a function call.
      
      I expect the code to contain bugs due to the size alone but I'll be
      watching and squashing them and feeding out new patches as it goes.
      
      Because the buffers now dynamically expand you should only run out of
      buffering when the kernel runs out of memory for real.  That means a lot of
      the horrible hacks high performance drivers used to do just aren't needed any
      more.
      
      Description:
      
      tty_insert_flip_char is an old API and continues to work as before, as does
      tty_flip_buffer_push() [this is why many drivers dont need modification].  It
      does now also return the number of chars inserted
      
      There are also
      
      tty_buffer_request_room(tty, len)
      
      which asks for a buffer block of the length requested and returns the space
      found.  This improves efficiency with hardware that knows how much to
      transfer.
      
      and tty_insert_flip_string_flags(tty, str, flags, len)
      
      to insert a string of characters and flags
      
      For a smart interface the usual code is
      
          len = tty_request_buffer_room(tty, amount_hardware_says);
          tty_insert_flip_string(tty, buffer_from_card, len);
      
      More description!
      
      At the moment tty buffers are attached directly to the tty.  This is causing a
      lot of the problems related to tty layer locking, also problems at high speed
      and also with bursty data (such as occurs in virtualised environments)
      
      I'm working on ripping out the flip buffers and replacing them with a pool of
      dynamically allocated buffers.  This allows both for old style "byte I/O"
      devices and also helps virtualisation and smart devices where large blocks of
      data suddenely materialise and need storing.
      
      So far so good.  Lots of drivers reference tty->flip.*.  Several of them also
      call directly and unsafely into function pointers it provides.  This will all
      break.  Most drivers can use tty_insert_flip_char which can be kept as an API
      but others need more.
      
      At the moment I've added the following interfaces, if people think more will
      be needed now is a good time to say
      
       int tty_buffer_request_room(tty, size)
      
      Try and ensure at least size bytes are available, returns actual room (may be
      zero).  At the moment it just uses the flipbuf space but that will change.
      Repeated calls without characters being added are not cumulative.  (ie if you
      call it with 1, 1, 1, and then 4 you'll have four characters of space.  The
      other functions will also try and grow buffers in future but this will be a
      more efficient way when you know block sizes.
      
       int tty_insert_flip_char(tty, ch, flag)
      
      As before insert a character if there is room.  Now returns 1 for success, 0
      for failure.
      
       int tty_insert_flip_string(tty, str, len)
      
      Insert a block of non error characters.  Returns the number inserted.
      
       int tty_prepare_flip_string(tty, strptr, len)
      
      Adjust the buffer to allow len characters to be added.  Returns a buffer
      pointer in strptr and the length available.  This allows for hardware that
      needs to use functions like insl or mencpy_fromio.
      Signed-off-by: default avatarAlan Cox <alan@redhat.com>
      Cc: Paul Fulghum <paulkf@microgate.com>
      Signed-off-by: default avatarHirokazu Takata <takata@linux-m32r.org>
      Signed-off-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
      Signed-off-by: default avatarJohn Hawkes <hawkes@sgi.com>
      Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      33f0f88f
    • Tobias Klauser's avatar
      [PATCH] drivers/char: Use ARRAY_SIZE macro · fe971071
      Tobias Klauser authored
      Use ARRAY_SIZE macro instead of sizeof(x)/sizeof(x[0]) and remove
      duplicates of ARRAY_SIZE.
      Signed-off-by: default avatarTobias Klauser <tklauser@nuerscht.ch>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      fe971071
  14. 09 Nov, 2005 1 commit
    • Olaf Hering's avatar
      [PATCH] changing CONFIG_LOCALVERSION rebuilds too much, for no good reason · 733482e4
      Olaf Hering authored
      This patch removes almost all inclusions of linux/version.h.  The 3
      #defines are unused in most of the touched files.
      
      A few drivers use the simple KERNEL_VERSION(a,b,c) macro, which is
      unfortunatly in linux/version.h.
      
      There are also lots of #ifdef for long obsolete kernels, this was not
      touched.  In a few places, the linux/version.h include was move to where
      the LINUX_VERSION_CODE was used.
      
      quilt vi `find * -type f -name "*.[ch]"|xargs grep -El '(UTS_RELEASE|LINUX_VERSION_CODE|KERNEL_VERSION|linux/version.h)'|grep -Ev '(/(boot|coda|drm)/|~$)'`
      
      search pattern:
      /UTS_RELEASE\|LINUX_VERSION_CODE\|KERNEL_VERSION\|linux\/\(utsname\|version\).h
      Signed-off-by: default avatarOlaf Hering <olh@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      733482e4
  15. 07 Nov, 2005 3 commits
  16. 10 Sep, 2005 1 commit
  17. 06 Sep, 2005 1 commit
    • Al Viro's avatar
      [MOXA]: Fix this driver properly. · 1d25240f
      Al Viro authored
      Actually, proper fix of that breakage is embarrassingly simple - it's yet
      another gratitious leftover include of asm/segment.h, so incremental to the
      previos would be removal of that BROKEN and removal of bogus include from
      mxser.c itself.
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1d25240f
  18. 06 Jun, 2005 1 commit
  19. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      
      Let it rip!
      1da177e4