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    SubjectRe: [linux-next][PATCH] cpumask:cpumask_of_node-ia64 fix
    KOSAKI Motohiro wrote:
    > ===
    > Subject: [PATCH] cpumask:cpumask_of_node-ia64 fix
    > Impact: bug fix
    >
    > commit 07c636deede53ff3e96d54df0ece2c838e61951f introduce new CPU mask API and change cpu_mask variable type.
    >
    > -----------------------------------------------
    > - cpumask_t cpu_mask;
    > + const struct cpumask *cpu_mask;
    > --------------------------------------------------
    >
    >
    > However, its change is incomplete. in build time, compiler output following type mismatch warnings.
    >
    > arch/ia64/kernel/iosapic.c:708: warning: passing argument 2 of '__cpu_clear' from incompatible pointer type
    > arch/ia64/kernel/iosapic.c:711: warning: passing argument 1 of '__cpus_weight' from incompatible pointer type
    > arch/ia64/kernel/iosapic.c:719: warning: passing argument 1 of '__first_cpu' from incompatible pointer type
    > arch/ia64/kernel/iosapic.c:720: warning: passing argument 2 of '__next_cpu' from incompatible pointer type

    Good catch, however ...
    >
    >
    > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    > CC: "Luck, Tony" <tony.luck@intel.com>
    > CC: Rusty Russell <rusty@rustcorp.com.au>
    > ---
    > arch/ia64/kernel/iosapic.c | 10 +++++-----
    > 1 file changed, 5 insertions(+), 5 deletions(-)
    >
    > Index: b/arch/ia64/kernel/iosapic.c
    > ===================================================================
    > --- a/arch/ia64/kernel/iosapic.c
    > +++ b/arch/ia64/kernel/iosapic.c
    > @@ -695,7 +695,7 @@ get_target_cpu (unsigned int gsi, int ir
    > #ifdef CONFIG_NUMA
    > {
    > int num_cpus, cpu_index, iosapic_index, numa_cpu, i = 0;
    > - const struct cpumask *cpu_mask;
    > + struct cpumask *cpu_mask;
    >
    > iosapic_index = find_iosapic(gsi);
    > if (iosapic_index < 0 ||
    > @@ -705,10 +705,10 @@ get_target_cpu (unsigned int gsi, int ir
    > cpu_mask = cpumask_of_node(iosapic_lists[iosapic_index].node);
    > for_each_cpu_and(numa_cpu, cpu_mask, &domain) {
    > if (!cpu_online(numa_cpu))
    > - cpu_clear(numa_cpu, cpu_mask);
    > + cpu_clear(numa_cpu, *cpu_mask);

    ... you cannot modify the read-only cpumask_of_node map. Suggested alternative below.

    > }
    >
    > - num_cpus = cpus_weight(cpu_mask);
    > + num_cpus = cpus_weight(*cpu_mask);
    >
    > if (!num_cpus)
    > goto skip_numa_setup;
    > @@ -716,8 +716,8 @@ get_target_cpu (unsigned int gsi, int ir
    > /* Use irq assignment to distribute across cpus in node */
    > cpu_index = irq % num_cpus;
    >
    > - for (numa_cpu = first_cpu(cpu_mask) ; i < cpu_index ; i++)
    > - numa_cpu = next_cpu(numa_cpu, cpu_mask);
    > + for (numa_cpu = first_cpu(*cpu_mask) ; i < cpu_index ; i++)
    > + numa_cpu = next_cpu(numa_cpu, *cpu_mask);
    >
    > if (numa_cpu != NR_CPUS)
    > return cpu_physical_id(numa_cpu);
    >
    >
    > --
    ---
    arch/ia64/kernel/iosapic.c | 16 ++++++++--------
    1 file changed, 8 insertions(+), 8 deletions(-)

    --- linux-2.6-next.orig/arch/ia64/kernel/iosapic.c
    +++ linux-2.6-next/arch/ia64/kernel/iosapic.c
    @@ -703,23 +703,23 @@ get_target_cpu (unsigned int gsi, int ir
    goto skip_numa_setup;

    cpu_mask = cpumask_of_node(iosapic_lists[iosapic_index].node);
    + num_cpus = 0;
    for_each_cpu_and(numa_cpu, cpu_mask, &domain) {
    - if (!cpu_online(numa_cpu))
    - cpu_clear(numa_cpu, cpu_mask);
    + if (cpu_online(numa_cpu))
    + num_cpus++;
    }

    - num_cpus = cpus_weight(cpu_mask);
    -
    if (!num_cpus)
    goto skip_numa_setup;

    /* Use irq assignment to distribute across cpus in node */
    cpu_index = irq % num_cpus;

    - for (numa_cpu = first_cpu(cpu_mask) ; i < cpu_index ; i++)
    - numa_cpu = next_cpu(numa_cpu, cpu_mask);
    + for_each_cpu_and(numa_cpu, cpu_mask, cpu_online_mask)
    + if (i++ >= cpu_index)
    + break;

    - if (numa_cpu != NR_CPUS)
    + if (numa_cpu < nr_cpu_ids)
    return cpu_physical_id(numa_cpu);
    }
    skip_numa_setup:
    @@ -730,7 +730,7 @@ skip_numa_setup:
    * case of NUMA.)
    */
    do {
    - if (++cpu >= NR_CPUS)
    + if (++cpu >= nr_cpu_ids)
    cpu = 0;
    } while (!cpu_online(cpu) || !cpu_isset(cpu, domain));

    ---

    One aside, I'm not sure of ia64, but x86_64 keeps only online cpus in the cpumask_of_node_map.
    IOW, if a cpu goes offline, it's removed from the map. So the whole and'ing thing above may
    be unnecessary.


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