Re: [BUG] scsi: hpsa: how to destroy your files

Jon Mason
2011-09-01T21:50:45Z

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On Thu, Sep 1, 2011 at 3:44 PM, <scameron@beardog.cce.hp.com> wrote:
> On Thu, Sep 01, 2011 at 01:09:30PM -0700, Jesse Barnes wrote:
>> On Thu, 1 Sep 2011 15:03:49 -0500
>> scameron@beardog.cce.hp.com wrote:
>>
>> > On Thu, Sep 01, 2011 at 12:59:38PM -0700, Jesse Barnes wrote:
>> > > On Thu, 01 Sep 2011 11:50:38 -0700
>> > > James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
>> > >
>> > > > On Thu, 2011-09-01 at 10:58 -0700, Roland Dreier wrote:
>> > > > > > OK I found the bad commit,I got lucky... I lost some files but my
>> > > > > > machine was able to complete the bisection. CC involved people
>> > > > >
>> > > > > > # bad: [b03e7495a862b028294f59fc87286d6d78ee7fa1] PCI: Set PCI-E Max Payload Size on fabric
>> > > > >
>> > > > > Hi Eric,
>> > > > >
>> > > > > I guess it would be useful to see "lspci -vv" output with a "good" kernel
>> > > > > and with that bad patch applied.  Most likely we should see some difference
>> > > > > somewhere in the MaxPayload fields in the PCI Express capability of
>> > > > > some device.
>> > > > >
>> > > > > Either the RAID controller or something else lies, and puts a value
>> > > > > in the DevCap that it can't actually support, or else the patch is
>> > > > > buggy and puts something out of range in a DevCtl somewhere.
>> > > >
>> > > >
>> > > > While we investigate, I think the problems produced by the patch (data
>> > > > corruption) are serious enough to warrant reverting it, please Jesse.
>> > >
>> > > Hm I haven't been paying attention to the compromise thread; how should
>> > > I share these changes?  Is master.kernel.org down indefinitely?  Is
>> > > there a new server at kernel.org I can use?
>> >
>> > I can't answer that question, but I would like a copy of your revert
>> > patch(es) to test (as a simple patch --reverse of the original commit on the 3.1-rc4
>> > tree didn't go in cleanly).
>>
>> Attached is the series.  Applies on top of my for-linus branch.
>
> Thanks.  I tried them out vs. 3.1-rc4, and they applied cleanly and
> make things work on my BL460g7.

I believe modifying the MRRS values is what is causing the issues.
Can you try the attached patch and verify that it also resolves the
issue?

Thanks,
Jon

> -- steve
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[-- Attachment #2: mrrs_removal.patch --]
[-- Type: text/x-patch, Size: 1848 bytes --]

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8473727..d896c5e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1394,41 +1394,6 @@ static void pcie_write_mps(struct pci_dev *dev, int mps)
dev_err(&dev->dev, "Failed attempting to set the MPS\n");
}

-static void pcie_write_mrrs(struct pci_dev *dev, int mps)
-{
- int rc, mrrs;
-
- if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
- int dev_mpss = 128 << dev->pcie_mpss;
-
- /* For Max performance, the MRRS must be set to the largest
- * supported value. However, it cannot be configured larger
- * than the MPS the device or the bus can support. This assumes
- * that the largest MRRS available on the device cannot be
- * smaller than the device MPSS.
- */
- mrrs = mps < dev_mpss ? mps : dev_mpss;
- } else
- /* In the "safe" case, configure the MRRS for fairness on the
- * bus by making all devices have the same size
- */
- mrrs = mps;
-
-
- /* MRRS is a R/W register. Invalid values can be written, but a
- * subsiquent read will verify if the value is acceptable or not.
- * If the MRRS value provided is not acceptable (e.g., too large),
- * shrink the value until it is acceptable to the HW.
- */
- while (mrrs != pcie_get_readrq(dev) && mrrs >= 128) {
- rc = pcie_set_readrq(dev, mrrs);
- if (rc)
- dev_err(&dev->dev, "Failed attempting to set the MRRS\n");
-
- mrrs /= 2;
- }
-}
-
static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
{
int mps = 128 << *(u8 *)data;
@@ -1440,7 +1405,6 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));

pcie_write_mps(dev, mps);
- pcie_write_mrrs(dev, mps);

dev_info(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));