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  1. 22 Oct, 2010 12 commits
    • Tejun Heo's avatar
      libata: implement cross-port EH exclusion · c0c362b6
      Tejun Heo authored 
      In libata, the non-EH code paths should always take and release
ap->lock explicitly when accessing hardware or shared data structures.
However, once EH is active, it's assumed that the port is owned by EH
and EH methods don't explicitly take ap->lock unless race from irq
handler or other code paths are expected.  However, libata EH didn't
guarantee exclusion among EHs for ports of the same host.  IOW,
multiple EHs may execute in parallel on multiple ports of the same
controller.

In many cases, especially in SATA, the ports are completely
independent of each other and this doesn't cause problems; however,
there are cases where different ports share the same resource, which
lead to obscure timing related bugs such as the one fixed by commit
213373cf (ata_piix: fix locking around SIDPR access).

This patch implements exclusion among EHs of the same host.  When EH
begins, it acquires per-host EH ownership by calling ata_eh_acquire().
When EH finishes, the ownership is released by calling
ata_eh_release().  EH ownership is also released whenever the EH
thread goes to sleep from ata_msleep() or explicitly and reacquired
after waking up.

This ensures that while EH is actively accessing the hardware, it has
exclusive access to it while allowing EHs to interleave and progress
in parallel as they hit waiting stages, which dominate the time spent
in EH.  This achieves cross-port EH exclusion without pervasive and
fragile changes while still allowing parallel EH for the most part.

This was first reported by yuanding02@gmail.com more than three years
ago in the following bugzilla.  :-)

  https://bugzilla.kernel.org/show_bug.cgi?id=8223Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reported-by: yuanding02@gmail.com
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      c0c362b6
    • Tejun Heo's avatar
      libata: add @ap to ata_wait_register() and introduce ata_msleep() · 97750ceb
      Tejun Heo authored 
      Add optional @ap argument to ata_wait_register() and replace msleep()
calls with ata_msleep() which take optional @ap in addition to the
duration.  These will be used to implement EH exclusion.

This patch doesn't cause any behavior difference.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      97750ceb
    • Tejun Heo's avatar
      ata_piix: implement LPM support · a97c4006
      Tejun Heo authored 
      Now that DIPM can be used independently from HIPM, ata_piix can
support LPM too.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      a97c4006
    • Tejun Heo's avatar
      libata: implement LPM support for port multipliers · 6c8ea89c
      Tejun Heo authored 
      Port multipliers can do DIPM on fan-out links fine.  Implement support
for it.  Tested w/ SIMG 57xx and marvell PMPs.  Both the host and
fan-out links enter power save modes nicely.

SIMG 37xx and 47xx report link offline on SStatus causing EH to detach
the devices.  Blacklisted.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      6c8ea89c
    • Tejun Heo's avatar
      libata: reimplement link power management · 6b7ae954
      Tejun Heo authored 
      The current LPM implementation has the following issues.

* Operation order isn't well thought-out.  e.g. HIPM should be
  configured after IPM in SControl is properly configured.  Not the
  other way around.

* Suspend/resume paths call ata_lpm_enable/disable() which must only
  be called from EH context directly.  Also, ata_lpm_enable/disable()
  were called whether LPM was in use or not.

* Implementation is per-port when it should be per-link.  As a result,
  it can't be used for controllers with slave links or PMP.

* LPM state isn't managed consistently.  After a link reset for
  whatever reason including suspend/resume the actual LPM state would
  be reset leaving ap->lpm_policy inconsistent.

* Generic/driver-specific logic boundary isn't clear.  Currently,
  libahci has to mangle stuff which libata EH proper should be
  handling.  This makes the implementation unnecessarily complex and
  fragile.

* Tied to ALPM.  Doesn't consider DIPM only cases and doesn't check
  whether the device allows HIPM.

* Error handling isn't implemented.

Given the extent of mismatch with the rest of libata, I don't think
trying to fix it piecewise makes much sense.  This patch reimplements
LPM support.

* The new implementation is per-link.  The target policy is still
  port-wide (ap->target_lpm_policy) but all the mechanisms and states
  are per-link and integrate well with the rest of link abstraction
  and can work with slave and PMP links.

* Core EH has proper control of LPM state.  LPM state is reconfigured
  when and only when reconfiguration is necessary.  It makes sure that
  LPM state is reset when probing for new device on the link.
  Controller agnostic logic is now implemented in libata EH proper and
  driver implementation only has to deal with controller specifics.

* Proper error handling.  LPM config failure is attributed to the
  device on the link and LPM is disabled for the link if it fails
  repeatedly.

* ops->enable/disable_pm() are replaced with single ops->set_lpm()
  which takes @policy and @hints.  This simplifies driver specific
  implementation.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      6b7ae954
    • Tejun Heo's avatar
      libata: implement sata_link_scr_lpm() and make ata_dev_set_feature() global · 1152b261
      Tejun Heo authored 
      Link power management is about to be reimplemented.  Prepare for it.

* Implement sata_link_scr_lpm().

* Drop static from ata_dev_set_feature() and make it available to
  other libata files.

* Trivial whitespace adjustments.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      1152b261
    • Tejun Heo's avatar
      libata: clean up lpm related symbols and sysfs show/store functions · c93b263e
      Tejun Heo authored 
      Link power management related symbols are in confusing state w/ mixed
usages of lpm, ipm and pm.  This patch cleans up lpm related symbols
and sysfs show/store functions as follows.

* lpm states - NOT_AVAILABLE, MIN_POWER, MAX_PERFORMANCE and
  MEDIUM_POWER are renamed to ATA_LPM_UNKNOWN and
  ATA_LPM_{MIN|MAX|MED}_POWER.

* Pre/postfixes are unified to lpm.

* sysfs show/store functions for link_power_management_policy were
  curiously named get/put and unnecessarily complex.  Renamed to
  show/store and simplified.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      c93b263e
    • Luck, Tony's avatar
      [libata] Fix section mismatch: ata_sff_exit · c43d559f
      Luck, Tony authored 
      This build error showed up in linux-next tag next-20100820 for ia64:

WARNING: vmlinux.o(.init.text+0x4a952): Section mismatch in reference from the function ata_init() to the function .exit.text:ata_sff_exit()
The function __init ata_init() references
a function __exit ata_sff_exit().
This is often seen when error handling in the init function
uses functionality in the exit path.
The fix is often to remove the __exit annotation of
ata_sff_exit() so it may be used outside an exit section.

Sure enough, dropping the __exit fixes the problem.
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      c43d559f
    • Jeff Garzik's avatar
      drivers/ata/libata-transport.c: include linux/slab.h · 6a2148c6
      Jeff Garzik authored 
      Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      6a2148c6
    • Grant Grundler's avatar
      [libata] support for > 512 byte sectors (e.g. 4K Native) · 295124dc
      Grant Grundler authored 
      This change enables my x86 machine to recognize and talk to a
"Native 4K" SATA device.

When I started working on this, I didn't know Matthew Wilcox had
posted a similar patch 2 years ago:
  http://git.kernel.org/?p=linux/kernel/git/willy/ata.git;a=shortlog;h=refs/heads/ata-large-sectors

Gwendal Grignou pointed me at the the above code and small portions of
this patch include Matthew's work. That's why Mathew is first on the
"Signed-off-by:". I've NOT included his use of a bitmap to determine
512 vs Native for ATA command block size - just used a simple table.
And bugs are almost certainly mine.

Lastly, the patch has been tested with a native 4K 'Engineering
Sample' drive provided by Hitachi GST.
Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: default avatarGrant Grundler <grundler@google.com>
Reviewed-by: default avatarGwendal Grignou <gwendal@google.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      295124dc
    • Tejun Heo's avatar
      libata: always use ata_qc_complete_multiple() for NCQ command completions · 1aadf5c3
      Tejun Heo authored 
      Currently, sata_fsl, mv and nv call ata_qc_complete() multiple times
from their interrupt handlers to indicate completion of NCQ commands.
This limits the visibility the libata core layer has into how commands
are being executed and completed, which is necessary to support IRQ
expecting in generic way.  libata already has an interface to complete
multiple commands at once - ata_qc_complete_multiple() which ahci and
sata_sil24 already use.

This patch updates the three drivers to use ata_qc_complete_multiple()
too and updates comments on ata_qc_complete[_multiple]() regarding
their usages with NCQ completions.  This change not only provides
better visibility into command execution to the core layer but also
simplifies low level drivers.

* sata_fsl: It already builds done_mask.  Conversion is straight
  forward.

* sata_mv: mv_process_crpb_response() no longer checks for illegal
  completions, it just returns whether the tag is completed or not.
  mv_process_crpb_entries() builds done_mask from it and passes it to
  ata_qc_complete_multiple() which will check for illegal completions.

* sata_nv adma: Similar to sata_mv.  nv_adma_check_cpb() now just
  returns the tag status and nv_adma_interrupt() builds done_mask from
  it and passes it to ata_qc_complete_multiple().

* sata_nv swncq: It already builds done_mask.  Drop unnecessary
  illegal transition checks and call ata_qc_complete_multiple().

In the long run, it might be a good idea to make ata_qc_complete()
whine if called when multiple NCQ commands are in flight.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Ashish Kalra <ashish.kalra@freescale.com>
Cc: Saeed Bishara <saeed@marvell.com>
Cc: Mark Lord <liml@rtr.ca>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      1aadf5c3
    • Gwendal Grignou's avatar
      [libata] Add ATA transport class · d9027470
      Gwendal Grignou authored 
      This is a scheleton for libata transport class.
All information is read only, exporting information from libata:
- ata_port class: one per ATA port
- ata_link class: one per ATA port or 15 for SATA Port Multiplier
- ata_device class: up to 2 for PATA link, usually one for SATA.
Signed-off-by: default avatarGwendal Grignou <gwendal@google.com>
Reviewed-by: default avatarGrant Grundler <grundler@google.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
      d9027470
  3. 20 Oct, 2010 5 commits
  5. 19 Oct, 2010 7 commits
  7. 18 Oct, 2010 16 commits
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