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@xxxxxxxxx>
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
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