1. 06 2月, 2013 5 次提交
  2. 05 2月, 2013 25 次提交
  3. 01 2月, 2013 6 次提交
  4. 31 1月, 2013 4 次提交
    • A
      MIPS: Function tracer: Fix broken function tracing · 58b69401
      Al Cooper 提交于
      Function tracing is currently broken for all 32 bit MIPS platforms.
      When tracing is enabled, the kernel immediately hangs on boot.
      This is a result of commit b732d439
      that changes the kernel/trace/Kconfig file so that is no longer
      forces FRAME_POINTER when FUNCTION_TRACING is enabled.
      
      MIPS frame pointers are generally considered to be useless because
      they cannot be used to unwind the stack. Unfortunately the MIPS
      function tracing code has bugs that are masked by the use of frame
      pointers. This commit fixes the bugs so that MIPS frame pointers
      don't need to be enabled.
      
      The bugs are a result of the odd calling sequence used to call the trace
      routine. This calling sequence is inserted into every traceable function
      when the tracing CONFIG option is enabled. This sequence is generated
      for 32bit MIPS platforms by the compiler via the "-pg" flag.
      
      Part of the sequence is "addiu sp,sp,-8" in the delay slot after every
      call to the trace routine "_mcount" (some legacy thing where 2 arguments
      used to be pushed on the stack). The _mcount routine is expected to
      adjust the sp by +8 before returning.  So when not disabled, the original
      jalr and addiu will be there, so _mcount has to adjust sp.
      
      The problem is that when tracing is disabled for a function, the
      "jalr _mcount" instruction is replaced with a nop, but the
      "addiu sp,sp,-8" is still executed and the stack pointer is left
      trashed. When frame pointers are enabled the problem is masked
      because any access to the stack is done through the frame
      pointer and the stack pointer is restored from the frame pointer when
      the function returns.
      
      This patch writes two nops starting at the address of the "jalr _mcount"
      instruction whenever tracing is disabled. This means that the
      "addiu sp,sp.-8" will be converted to a nop along with the "jalr".  When
      disabled, there will be two nops.
      
      This is SMP safe because the first time this happens is during
      ftrace_init() which is before any other processor has been started.
      Subsequent calls to enable/disable tracing when other CPUs ARE running
      will still be safe because the enable will only change the first nop
      to a "jalr" and the disable, while writing 2 nops, will only be changing
      the "jalr". This patch also stops using stop_machine() to call the
      tracer enable/disable routines and calls them directly because the
      routines are SMP safe.
      
      When the kernel first boots we have to be able to handle the gcc
      generated jalr, addui sequence until ftrace_init gets a chance to run
      and change the sequence. At this point mcount just adjusts the stack
      and returns. When ftrace_init runs, we convert the jalr/addui to nops.
      Then whenever tracing is enabled we convert the first nop to a "jalr
      mcount+8". The mcount+8 entry point skips the stack adjust.
      
      [ralf@linux-mips.org: Folded in  Steven Rostedt's build fix.]
      Signed-off-by: NAl Cooper <alcooperx@gmail.com>
      Cc: rostedt@goodmis.org
      Cc: ddaney.cavm@gmail.com
      Cc: linux-mips@linux-mips.org
      Cc: linux-kernel@vger.kernel.org
      Patchwork: https://patchwork.linux-mips.org/patch/4806/
      Patchwork: https://patchwork.linux-mips.org/patch/4841/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      58b69401
    • A
      dm: fix write same requests counting · fe7af2d3
      Alasdair G Kergon 提交于
      When processing write same requests, fix dm to send the configured
      number of WRITE SAME requests to the target rather than the number of
      discards, which is not always the same.
      
      Device-mapper WRITE SAME support was introduced by commit
      23508a96 ("dm: add WRITE SAME support").
      Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      Acked-by: NMike Snitzer <snitzer@redhat.com>
      fe7af2d3
    • S
      mips: Move __virt_addr_valid() to a place for MIPS 64 · 196897a2
      Steven Rostedt 提交于
      Commit d3ce8843 "MIPS: Fix modpost error in modules attepting to use
      virt_addr_valid()" moved __virt_addr_valid() from a macro in a header
      file to a function in ioremap.c. But ioremap.c is only compiled for MIPS
      32, and not for MIPS 64.
      
      When compiling for my yeeloong2, which supposedly supports hibernation,
      which compiles kernel/power/snapshot.c which calls virt_addr_valid(), I
      got this error:
      
        LD      init/built-in.o
      kernel/built-in.o: In function `memory_bm_free':
      snapshot.c:(.text+0x4c9c4): undefined reference to `__virt_addr_valid'
      snapshot.c:(.text+0x4ca58): undefined reference to `__virt_addr_valid'
      kernel/built-in.o: In function `snapshot_write_next':
      (.text+0x4e44c): undefined reference to `__virt_addr_valid'
      kernel/built-in.o: In function `snapshot_write_next':
      (.text+0x4e890): undefined reference to `__virt_addr_valid'
      make[1]: *** [vmlinux] Error 1
      make: *** [sub-make] Error 2
      
      I suspect that __virt_addr_valid() is fine for mips 64. I moved it to
      mmap.c such that it gets compiled for mips 64 and 32.
      Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-mips@linux-mips.org
      Patchwork: https://patchwork.linux-mips.org/patch/4842/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      196897a2
    • M
      dm thin: fix queue limits stacking · 0f640dca
      Mike Snitzer 提交于
      thin_io_hints() is blindly copying the queue limits from the thin-pool
      which can lead to incorrect limits being set.  The fix here simply
      deletes the thin_io_hints() hook which leaves the existing stacking
      infrastructure to set the limits correctly.
      
      When a thin-pool uses an MD device for the data device a thin device
      from the thin-pool must respect MD's constraints about disallowing a bio
      from spanning multiple chunks.  Otherwise we can see problems.  If the raid0
      chunksize is 1152K and thin-pool chunksize is 256K I see the following
      md/raid0 error (with extra debug tracing added to thin_endio) when
      mkfs.xfs is executed against the thin device:
      
      md/raid0:md99: make_request bug: can't convert block across chunks or bigger than 1152k 6688 127
      device-mapper: thin: bio sector=2080 err=-5 bi_size=130560 bi_rw=17 bi_vcnt=32 bi_idx=0
      
      This extra DM debugging shows that the failing bio is spanning across
      the first and second logical 1152K chunk (sector 2080 + 255 takes the
      bio beyond the first chunk's boundary of sector 2304).  So the bio
      splitting that DM is doing clearly isn't respecting the MD limits.
      
      max_hw_sectors_kb is 127 for both the thin-pool and thin device
      (queue_max_hw_sectors returns 255 so we'll excuse sysfs's lack of
      precision).  So this explains why bi_size is 130560.
      
      But the thin device's max_hw_sectors_kb should be 4 (PAGE_SIZE) given
      that it doesn't have a .merge function (for bio_add_page to consult
      indirectly via dm_merge_bvec) yet the thin-pool does sit above an MD
      device that has a compulsory merge_bvec_fn.  This scenario is exactly
      why DM must resort to sending single PAGE_SIZE bios to the underlying
      layer. Some additional context for this is available in the header for
      commit 8cbeb67a ("dm: avoid unsupported spanning of md stripe boundaries").
      
      Long story short, the reason a thin device doesn't properly get
      configured to have a max_hw_sectors_kb of 4 (PAGE_SIZE) is that
      thin_io_hints() is blindly copying the queue limits from the thin-pool
      device directly to the thin device's queue limits.
      
      Fix this by eliminating thin_io_hints.  Doing so is safe because the
      block layer's queue limits stacking already enables the upper level thin
      device to inherit the thin-pool device's discard and minimum_io_size and
      optimal_io_size limits that get set in pool_io_hints.  But avoiding the
      queue limits copy allows the thin and thin-pool limits to be different
      where it is important, namely max_hw_sectors_kb.
      Reported-by: NDaniel Browning <db@kavod.com>
      Signed-off-by: NMike Snitzer <snitzer@redhat.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      0f640dca