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Date: Tue, 14 Oct 2014 18:09:11 -0600 From: Bjorn Helgaas <bhelgaas@...gle.com> To: Chen Gang <gang.chen.5i5j@...il.com> Cc: konrad.wilk@...cle.com, boris.ostrovsky@...cle.com, david.vrabel@...rix.com, xen-devel@...ts.xenproject.org, linux-pci@...r.kernel.org, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH next] xen: pcifront: Process failure for pcifront_(re)scan_root() On Mon, Oct 06, 2014 at 11:04:45AM +0800, Chen Gang wrote: > When pcifront_rescan_root() or pcifront_scan_root() fails, need return > error code, neither set XenbusStateConnected state, just like the other > areas have done. > > For pcifront_rescan_root(), it will return error code ("num_roots = 0;", > skip xenbus_switch_state return value). > > For pcifront_scan_root(), it will return 0 ("num_roots = 0;", set 0 by > the return value of xenbus_switch_state, which always return 0, at > present). The changelog is somewhat confusing because it talks about the patch hunks in reverse order (the pcifront_scan_root() change is first in the patch, but the changelog mentions pcifront_rescan_root() first). I *think* this means: When pcifront_try_connect() finds no PCI roots, it falls back to calling pcifront_scan_root() for 0000:00. If that fails, it used to switch to XenbusStateConnected and return success (because xenbus_switch_state() currently always succeeds). If pcifront_scan_root() fails, leave the XenbusState unchanged and return an error code. Similarly, pcifront_attach_devices() falls back to calling pcifront_rescan_root() for 0000:00. If that fails, it used to switch to XenbusStateConnected and return an error code. If pcifront_rescan_root() fails, leave the XenbusState unchanged and return the error code. The "num_roots" part doesn't seem relevant to me. > Signed-off-by: Chen Gang <gang.chen.5i5j@...il.com> Konrad, if you want to take this, feel free. Otherwise, if you ack it and you think my changelog understanding makes sense, I can pick it up. It does seem odd that pcifront_attach_devices() ignores the xenbus_switch_state() return value while pcifront_try_connect() does not. But many other callers also ignore the return value, so maybe that's OK. Bjorn > --- > drivers/pci/xen-pcifront.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c > index 53df39a..d78d884 100644 > --- a/drivers/pci/xen-pcifront.c > +++ b/drivers/pci/xen-pcifront.c > @@ -866,6 +866,11 @@ static int pcifront_try_connect(struct pcifront_device *pdev) > xenbus_dev_error(pdev->xdev, err, > "No PCI Roots found, trying 0000:00"); > err = pcifront_scan_root(pdev, 0, 0); > + if (err) { > + xenbus_dev_fatal(pdev->xdev, err, > + "Error scanning PCI root 0000:00"); > + goto out; > + } > num_roots = 0; > } else if (err != 1) { > if (err == 0) > @@ -947,6 +952,11 @@ static int pcifront_attach_devices(struct pcifront_device *pdev) > xenbus_dev_error(pdev->xdev, err, > "No PCI Roots found, trying 0000:00"); > err = pcifront_rescan_root(pdev, 0, 0); > + if (err) { > + xenbus_dev_fatal(pdev->xdev, err, > + "Error scanning PCI root 0000:00"); > + goto out; > + } > num_roots = 0; > } else if (err != 1) { > if (err == 0) > -- > 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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