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Re: [Qemu-devel] [PATCH RFC 4/6] xen: Print and use errno where applicab
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH RFC 4/6] xen: Print and use errno where applicable. |
Date: |
Wed, 1 Jul 2015 14:01:07 +0100 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
On Mon, 29 Jun 2015, Konrad Rzeszutek Wilk wrote:
> In Xen 4.6 commit cd2f100f0f61b3f333d52d1737dd73f02daee592
> "libxc: Fix do_memory_op to return negative value on errors"
> made the libxc API less odd-ball: On errors, return value is
> -1 and error code is in errno. On success the return value
> is either 0 or an positive value.
>
> Since we could be running with an old toolstack in which the
> Exx value is in rc or the newer, we print both and return
> the -EXX depending on rc == -1 condition.
>
> Signed-off-by: Konrad Rzeszutek Wilk <address@hidden>
> ---
> xen-hvm.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/xen-hvm.c b/xen-hvm.c
> index 0408462..a92bc14 100644
> --- a/xen-hvm.c
> +++ b/xen-hvm.c
> @@ -345,11 +345,12 @@ go_physmap:
> unsigned long idx = pfn + i;
> xen_pfn_t gpfn = start_gpfn + i;
>
> + /* In Xen 4.6 rc is -1 and errno contains the error value. */
> rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn,
> idx, gpfn);
> if (rc) {
> DPRINTF("add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
> - PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);
> - return -rc;
> + PRI_xen_pfn" failed: %d (errno: %d)\n", idx, gpfn, rc,
> errno);
> + return rc == -1 ? -errno : -rc;
Printing both rc and errno is the right thing to do, but I am not sure
changing return value depending on the libxc version is a good idea.
Maybe we should be consistent and always return rc?
> }
> }
>
> @@ -422,11 +423,12 @@ static int xen_remove_from_physmap(XenIOState *state,
> xen_pfn_t idx = start_addr + i;
> xen_pfn_t gpfn = phys_offset + i;
>
> + /* In Xen 4.6 rc is -1 and errno contains the error value. */
> rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn,
> idx, gpfn);
> if (rc) {
> fprintf(stderr, "add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
> - PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);
> - return -rc;
> + PRI_xen_pfn" failed: %d (errno: %d)\n", idx, gpfn, rc,
> errno);
> + return rc == -1 ? -errno : -rc;
> }
> }
>
> --
> 2.1.0
>
- Re: [Qemu-devel] [PATCH RFC 4/6] xen: Print and use errno where applicable.,
Stefano Stabellini <=