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author | kfraser@localhost.localdomain <kfraser@localhost.localdomain> | 2007-05-24 15:25:35 +0100 |
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committer | kfraser@localhost.localdomain <kfraser@localhost.localdomain> | 2007-05-24 15:25:35 +0100 |
commit | c0a12ddfdcaaab607929917b857c039d9371c372 (patch) | |
tree | d98c64aa4ff2099240c2f6724d5945b7f9d4a492 | |
parent | be422ace19118d2bf8415bfcaeda9fdf06b50bd4 (diff) | |
download | xen-c0a12ddfdcaaab607929917b857c039d9371c372.tar.gz xen-c0a12ddfdcaaab607929917b857c039d9371c372.tar.bz2 xen-c0a12ddfdcaaab607929917b857c039d9371c372.zip |
ioemu: Attempt to setup tap interface up to 3 times.
As there is a (small) chance that vl.c:tap_open() fails (due to some
sort of race-condition in the Linux kernel, which is noted as a bug in
the source .../net/core/dev.c), we should attempt it again a couple of
times if it doesn't succeed on the first attempt. I think three times
in total is sufficient to avoid the problem.
If tap_open() fails, qemu-dm will exit, which means that the domain
dies - which is not such a good thing when attempting to restore a saved
domain [of course, it would be even worse if it started, but didn't
have networking - because there may not be a way to shut it down
cleanly without network].
Signed-off-by: Mats Petersson <mats.petersson@amd.com>
-rw-r--r-- | tools/ioemu/vl.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/tools/ioemu/vl.c b/tools/ioemu/vl.c index 32d5163b4e..b1fe292d9b 100644 --- a/tools/ioemu/vl.c +++ b/tools/ioemu/vl.c @@ -3399,7 +3399,7 @@ static int tap_open(char *ifname, int ifname_size) static int tap_open(char *ifname, int ifname_size) { struct ifreq ifr; - int fd, ret; + int fd, ret, retries = 0; fd = open("/dev/net/tun", O_RDWR); if (fd < 0) { @@ -3412,7 +3412,9 @@ static int tap_open(char *ifname, int ifname_size) pstrcpy(ifr.ifr_name, IFNAMSIZ, ifname); else pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d"); - ret = ioctl(fd, TUNSETIFF, (void *) &ifr); + do { + ret = ioctl(fd, TUNSETIFF, (void *) &ifr); + } while ((ret != 0) && (retries++ < 3)); if (ret != 0) { fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n"); close(fd); |