On Tue, 30 Jul 2019 16:39:52 +0000
Matan Azrad <ma...@mellanox.com> wrote:
> Hi
>
> From: Stephen Hemminger
> > On Tue, 30 Jul 2019 09:21:02 +0000
> > Matan Azrad <ma...@mellanox.com> wrote:
> >
> > > Hi Stephen
> > >
> > > From: Stephen Hemminger
> > > > From: Stephen Hemminger <sthem...@microsoft.com>
> > > >
> > > > The mp_server incorrectly allows a port mask that included hidden
> > > > ports and which later caused either lost packets or failed
> > > > initialization.
> > > >
> > > > This fixes explicitly checking that each bit in portmask is a valid
> > > > port before using it.
> > > >
> > > > Fixes: 5b7ba31148a8 ("ethdev: add port ownership")
> > > > Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
> > > > ---
> > > > .../client_server_mp/mp_server/args.c | 46 +++++++++++++------
> > > > .../client_server_mp/mp_server/args.h | 2 +-
> > > > .../client_server_mp/mp_server/init.c | 7 +--
> > > > 3 files changed, 35 insertions(+), 20 deletions(-)
> > > >
> > > > diff --git
> > > > a/examples/multi_process/client_server_mp/mp_server/args.c
> > > > b/examples/multi_process/client_server_mp/mp_server/args.c
> > > > index b0d8d7665c85..c1ab12ad00d1 100644
> > > > --- a/examples/multi_process/client_server_mp/mp_server/args.c
> > > > +++ b/examples/multi_process/client_server_mp/mp_server/args.c
> > > > @@ -10,6 +10,7 @@
> > > > #include <errno.h>
> > > >
> > > > #include <rte_memory.h>
> > > > +#include <rte_ethdev.h>
> > > > #include <rte_string_fns.h>
> > > >
> > > > #include "common.h"
> > > > @@ -34,6 +35,22 @@ usage(void)
> > > > , progname);
> > > > }
> > > >
> > > > +/**
> > > > + * Check if port is present in the system
> > > > + * It maybe owned by a device and should not be used.
> > > > + */
> > > > +static int
> > > > +port_is_present(uint16_t portid)
> > > > +{
> > > > + uint16_t id;
> > > > +
> > > > + RTE_ETH_FOREACH_DEV(id) {
> > > > + if (id == portid)
> > > > + return 1;
> > > > + }
> > > > + return 0;
> > > > +}
> > > > +
> > > > /**
> > > > * The ports to be used by the application are passed in
> > > > * the form of a bitmask. This function parses the bitmask @@
> > > > -41,31 +58,32 @@ usage(void)
> > > > * array variable
> > > > */
> > > > static int
> > > > -parse_portmask(uint8_t max_ports, const char *portmask)
> > > > +parse_portmask(const char *portmask)
> > > > {
> > > > char *end = NULL;
> > > > unsigned long pm;
> > > > - uint16_t count = 0;
> > > > + uint16_t count;
> > > >
> > > > if (portmask == NULL || *portmask == '\0')
> > > > return -1;
> > > >
> > > > /* convert parameter to a number and verify */
> > > > pm = strtoul(portmask, &end, 16);
> > > > - if (end == NULL || *end != '\0' || pm == 0)
> > > > + if (end == NULL || *end != '\0' || pm > UINT16_MAX || pm == 0)
> > > > return -1;
> > > >
> > > > /* loop through bits of the mask and mark ports */
> > > > - while (pm != 0){
> > > > - if (pm & 0x01){ /* bit is set in mask, use port */
> > > > - if (count >= max_ports)
> > > > - printf("WARNING: requested port %u not
> > > > present"
> > > > - " - ignoring\n", (unsigned)count);
> > > > - else
> > > > - ports->id[ports->num_ports++] = count;
> > > > + for (count = 0; pm != 0; pm >>= 1, ++count) {
> > > > + if ((pm & 0x1) == 0)
> > > > + continue;
> > > > +
> > > > + if (!port_is_present(count)) {
> > > > + printf("WARNING: requested port %u not present -
> > > > ignoring\n",
> > > > + count);
> > > > + continue;
> > > > }
> > > > - pm = (pm >> 1);
> > > > - count++;
> > > > +
> > > > + ports->id[ports->num_ports++] = count;
> > > > }
> > >
> > > Why not just to do something like:
> > >
> > > RTE_ETH_FOREACH_DEV(id) {
> > > If (pm & (1 << id)) {
> > > pm &= ~(1 << id)
> > > put in list
> > > }
> > > }
> > > If (pm)
> > > Warning
> > >
> >
> > No real reason, was just trying to keep existing logic flow
>
> This is an example for the users\developers, and you on it,
> I think this is a good chance to show how to do it in the correct way - O(n)
> instead O(n^2).
>
> Don't you think so?
>
> I suggest to adjust.
>
This is a toy example short loops, it doesn't matter.
It is important to catch case where portmask contains hidden ports.
