• Linus Torvalds's avatar
    Merge branch 'for-3.13/core' of git://git.kernel.dk/linux-block · 0910c0bd
    Linus Torvalds authored
    Pull block IO core updates from Jens Axboe:
     "This is the pull request for the core changes in the block layer for
      3.13.  It contains:
    
       - The new blk-mq request interface.
    
         This is a new and more scalable queueing model that marries the
         best part of the request based interface we currently have (which
         is fully featured, but scales poorly) and the bio based "interface"
         which the new drivers for high IOPS devices end up using because
         it's much faster than the request based one.
    
         The bio interface has no block layer support, since it taps into
         the stack much earlier.  This means that drivers end up having to
         implement a lot of functionality on their own, like tagging,
         timeout handling, requeue, etc.  The blk-mq interface provides all
         these.  Some drivers even provide a switch to select bio or rq and
         has code to handle both, since things like merging only works in
         the rq model and hence is faster for some workloads.  This is a
         huge mess.  Conversion of these drivers nets us a substantial code
         reduction.  Initial results on converting SCSI to this model even
         shows an 8x improvement on single queue devices.  So while the
         model was intended to work on the newer multiqueue devices, it has
         substantial improvements for "classic" hardware as well.  This code
         has gone through extensive testing and development, it's now ready
         to go.  A pull request is coming to convert virtio-blk to this
         model will be will be coming as well, with more drivers scheduled
         for 3.14 conversion.
    
       - Two blktrace fixes from Jan and Chen Gang.
    
       - A plug merge fix from Alireza Haghdoost.
    
       - Conversion of __get_cpu_var() from Christoph Lameter.
    
       - Fix for sector_div() with 64-bit divider from Geert Uytterhoeven.
    
       - A fix for a race between request completion and the timeout
         handling from Jeff Moyer.  This is what caused the merge conflict
         with blk-mq/core, in case you are looking at that.
    
       - A dm stacking fix from Mike Snitzer.
    
       - A code consolidation fix and duplicated code removal from Kent
         Overstreet.
    
       - A handful of block bug fixes from Mikulas Patocka, fixing a loop
         crash and memory corruption on blk cg.
    
       - Elevator switch bug fix from Tomoki Sekiyama.
    
      A heads-up that I had to rebase this branch.  Initially the immutable
      bio_vecs had been queued up for inclusion, but a week later, it became
      clear that it wasn't fully cooked yet.  So the decision was made to
      pull this out and postpone it until 3.14.  It was a straight forward
      rebase, just pruning out the immutable series and the later fixes of
      problems with it.  The rest of the patches applied directly and no
      further changes were made"
    
    * 'for-3.13/core' of git://git.kernel.dk/linux-block: (31 commits)
      block: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
      block: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
      block: Do not call sector_div() with a 64-bit divisor
      kernel: trace: blktrace: remove redundent memcpy() in compat_blk_trace_setup()
      block: Consolidate duplicated bio_trim() implementations
      block: Use rw_copy_check_uvector()
      block: Enable sysfs nomerge control for I/O requests in the plug list
      block: properly stack underlying max_segment_size to DM device
      elevator: acquire q->sysfs_lock in elevator_change()
      elevator: Fix a race in elevator switching and md device initialization
      block: Replace __get_cpu_var uses
      bdi: test bdi_init failure
      block: fix a probe argument to blk_register_region
      loop: fix crash if blk_alloc_queue fails
      blk-core: Fix memory corruption if blkcg_init_queue fails
      block: fix race between request completion and timeout handling
      blktrace: Send BLK_TN_PROCESS events to all running traces
      blk-mq: don't disallow request merges for req->special being set
      blk-mq: mq plug list breakage
      blk-mq: fix for flush deadlock
      ...
    0910c0bd
smp.c 18.2 KB