Merge branch 'writeback-workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into for-3.10/core

Tejun writes:

-----

This is the pull request for the earlier patchset[1] with the same
name.  It's only three patches (the first one was committed to
workqueue tree) but the merge strategy is a bit involved due to the
dependencies.

* Because the conversion needs features from wq/for-3.10,
  block/for-3.10/core is based on rc3, and wq/for-3.10 has conflicts
  with rc3, I pulled mainline (rc5) into wq/for-3.10 to prevent those
  workqueue conflicts from flaring up in block tree.

* Resolving the issue that Jan and Dave raised about debugging
  requires arch-wide changes.  The patchset is being worked on[2] but
  it'll have to go through -mm after these changes show up in -next,
  and not included in this pull request.

The three commits are located in the following git branch.

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git writeback-workqueue

Pulling it into block/for-3.10/core produces a conflict in
drivers/md/raid5.c between the following two commits.

  e3620a3ad5 ("MD RAID5: Avoid accessing gendisk or queue structs when not available")
  2f6db2a707 ("raid5: use bio_reset()")

The conflict is trivial - one removes an "if ()" conditional while the
other removes "rbi->bi_next = NULL" right above it.  We just need to
remove both.  The merged branch is available at

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git block-test-merge

so that you can use it for verification.  The test merge commit has
proper merge description.

While these changes are a bit of pain to route, they make code simpler
and even have, while minute, measureable performance gain[3] even on a
workload which isn't particularly favorable to showing the benefits of
this conversion.

----

Fixed up the conflict.

Conflicts:
	drivers/md/raid5.c

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 44 insertions, 15 deletions

diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 9204126f1560..a2278ba7fb27 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -17,6 +17,7 @@
 #include <xen/events.h>
 #include <asm/xen/pci.h>
 #include <asm/xen/hypervisor.h>
+#include <xen/interface/physdev.h>
 #include "pciback.h"
 #include "conf_space.h"
 #include "conf_space_quirks.h"
@@ -85,37 +86,52 @@ static struct pcistub_device *pcistub_device_alloc(struct pci_dev *dev)
 static void pcistub_device_release(struct kref *kref)
 {
         struct pcistub_device *psdev;
+        struct pci_dev *dev;
         struct xen_pcibk_dev_data *dev_data;
 
         psdev = container_of(kref, struct pcistub_device, kref);
-        dev_data = pci_get_drvdata(psdev->dev);
+        dev = psdev->dev;
+        dev_data = pci_get_drvdata(dev);
 
-        dev_dbg(&psdev->dev->dev, "pcistub_device_release\n");
+        dev_dbg(&dev->dev, "pcistub_device_release\n");
 
-        xen_unregister_device_domain_owner(psdev->dev);
+        xen_unregister_device_domain_owner(dev);
 
         /* Call the reset function which does not take lock as this
          * is called from "unbind" which takes a device_lock mutex.
          */
-        __pci_reset_function_locked(psdev->dev);
-        if (pci_load_and_free_saved_state(psdev->dev,
-                                          &dev_data->pci_saved_state)) {
-                dev_dbg(&psdev->dev->dev, "Could not reload PCI state\n");
-        } else
-                pci_restore_state(psdev->dev);
+        __pci_reset_function_locked(dev);
+        if (pci_load_and_free_saved_state(dev, &dev_data->pci_saved_state))
+                dev_dbg(&dev->dev, "Could not reload PCI state\n");
+        else
+                pci_restore_state(dev);
+
+        if (pci_find_capability(dev, PCI_CAP_ID_MSIX)) {
+                struct physdev_pci_device ppdev = {
+                        .seg = pci_domain_nr(dev->bus),
+                        .bus = dev->bus->number,
+                        .devfn = dev->devfn
+                };
+                int err = HYPERVISOR_physdev_op(PHYSDEVOP_release_msix,
+                                                &ppdev);
+
+                if (err)
+                        dev_warn(&dev->dev, "MSI-X release failed (%d)\n",
+                                 err);
+        }
 
         /* Disable the device */
-        xen_pcibk_reset_device(psdev->dev);
+        xen_pcibk_reset_device(dev);
 
         kfree(dev_data);
-        pci_set_drvdata(psdev->dev, NULL);
+        pci_set_drvdata(dev, NULL);
 
         /* Clean-up the device */
-        xen_pcibk_config_free_dyn_fields(psdev->dev);
-        xen_pcibk_config_free_dev(psdev->dev);
+        xen_pcibk_config_free_dyn_fields(dev);
+        xen_pcibk_config_free_dev(dev);
 
-        psdev->dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
-        pci_dev_put(psdev->dev);
+        dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
+        pci_dev_put(dev);
 
         kfree(psdev);
 }
@@ -355,6 +371,19 @@ static int pcistub_init_device(struct pci_dev *dev)
         if (err)
                 goto config_release;
 
+        if (pci_find_capability(dev, PCI_CAP_ID_MSIX)) {
+                struct physdev_pci_device ppdev = {
+                        .seg = pci_domain_nr(dev->bus),
+                        .bus = dev->bus->number,
+                        .devfn = dev->devfn
+                };
+
+                err = HYPERVISOR_physdev_op(PHYSDEVOP_prepare_msix, &ppdev);
+                if (err)
+                        dev_err(&dev->dev, "MSI-X preparation failed (%d)\n",
+                                err);
+        }
+
         /* We need the device active to save the state. */
         dev_dbg(&dev->dev, "save state of device\n");
         pci_save_state(dev);