1. 30 Aug, 2009 1 commit
    • Chris Wright's avatar
      PCI SR-IOV: correct broken resource alignment calculations · 6faf17f6
      Chris Wright authored
      An SR-IOV capable device includes an SR-IOV PCIe capability which
      describes the Virtual Function (VF) BAR requirements.  A typical SR-IOV
      device can support multiple VFs whose BARs must be in a contiguous region,
      effectively an array of VF BARs.  The BAR reports the size requirement
      for a single VF.  We calculate the full range needed by simply multiplying
      the VF BAR size with the number of possible VFs and create a resource
      spanning the full range.
      
      This all seems sane enough except it artificially inflates the alignment
      requirement for the VF BAR.  The VF BAR need only be aligned to the size
      of a single BAR not the contiguous range of VF BARs.  This can cause us
      to fail to allocate resources for the BAR despite the fact that we
      actually have enough space.
      
      This patch adds a thin PCI specific layer over the generic
      resource_alignment() function which is aware of the special nature of
      VF BARs and does sorting and allocation based on the smaller alignment
      requirement.
      
      I recognize that while resource_alignment is generic, it's basically a
      PCI helper.  An alternative to this patch is to add PCI VF BAR specific
      information to struct resource.  I opted for the extra layer rather than
      adding such PCI specific information to struct resource.  This does
      have the slight downside that we don't cache the BAR size and re-read
      for each alignment query (happens a small handful of times during boot
      for each VF BAR).
      Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Yu Zhao <yu.zhao@intel.com>
      Cc: stable@kernel.org
      Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
      6faf17f6
  2. 29 Aug, 2009 6 commits
  3. 28 Aug, 2009 7 commits
  4. 27 Aug, 2009 26 commits