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Violators will be prosecuted for from ; Mon, 23 Jul 2018 13:42:20 -0400 Subject: Re: [PATCH v07 1/9] hotplug/cpu: Conditionally acquire/release DRC index To: Michael Bringmann , linuxppc-dev@lists.ozlabs.org Cc: John Allen , Tyrel Datwyler , Thomas Falcon References: From: Nathan Fontenot Date: Mon, 23 Jul 2018 12:42:14 -0500 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Message-Id: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/13/2018 03:17 PM, Michael Bringmann wrote: > powerpc/cpu: Modify dlpar_cpu_add and dlpar_cpu_remove to allow the > skipping of DRC index acquire or release operations during the CPU > add or remove operations. This is intended to support subsequent > changes to provide a 'CPU readd' operation. > > Signed-off-by: Michael Bringmann > --- > Changes in patch: > -- Move new validity check added to pseries_smp_notifier > to another patch > -- Revise one of checks for 'acquire_drc' in dlpar_cpu_add. > -- Revise one of checks for 'release_drc' in dlpar_cpu_remove. > --- > arch/powerpc/platforms/pseries/hotplug-cpu.c | 71 +++++++++++++++----------- > 1 file changed, 40 insertions(+), 31 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c > index 6ef77ca..7ede3b0 100644 > --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c > +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c > @@ -432,7 +432,7 @@ static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index) > return found; > } > > -static ssize_t dlpar_cpu_add(u32 drc_index) > +static ssize_t dlpar_cpu_add(u32 drc_index, bool acquire_drc) > { > struct device_node *dn, *parent; > int rc, saved_rc; > @@ -457,19 +457,22 @@ static ssize_t dlpar_cpu_add(u32 drc_index) > return -EINVAL; > } > > - rc = dlpar_acquire_drc(drc_index); > - if (rc) { > - pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n", > - rc, drc_index); > - of_node_put(parent); > - return -EINVAL; > + if (acquire_drc) { > + rc = dlpar_acquire_drc(drc_index); > + if (rc) { > + pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n", > + rc, drc_index); > + of_node_put(parent); > + return -EINVAL; > + } > } > > dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent); > if (!dn) { > pr_warn("Failed call to configure-connector, drc index: %x\n", > drc_index); > - dlpar_release_drc(drc_index); > + if (acquire_drc) > + dlpar_release_drc(drc_index); > of_node_put(parent); > return -EINVAL; > } > @@ -484,9 +487,11 @@ static ssize_t dlpar_cpu_add(u32 drc_index) > pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n", > dn->name, rc, drc_index); > > - rc = dlpar_release_drc(drc_index); > - if (!rc) > - dlpar_free_cc_nodes(dn); > + if (acquire_drc) { > + rc = dlpar_release_drc(drc_index); > + if (!rc) > + dlpar_free_cc_nodes(dn); > + } > > return saved_rc; > } > @@ -498,7 +503,7 @@ static ssize_t dlpar_cpu_add(u32 drc_index) > dn->name, rc, drc_index); > > rc = dlpar_detach_node(dn); > - if (!rc) > + if (!rc && acquire_drc) > dlpar_release_drc(drc_index); > > return saved_rc; > @@ -566,7 +571,8 @@ static int dlpar_offline_cpu(struct device_node *dn) > > } > > -static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index) > +static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index, > + bool release_drc) > { > int rc; > > @@ -579,12 +585,14 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index) > return -EINVAL; > } > > - rc = dlpar_release_drc(drc_index); > - if (rc) { > - pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n", > - drc_index, dn->name, rc); > - dlpar_online_cpu(dn); > - return rc; > + if (release_drc) { > + rc = dlpar_release_drc(drc_index); > + if (rc) { > + pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n", > + drc_index, dn->name, rc); > + dlpar_online_cpu(dn); > + return rc; > + } > } > > rc = dlpar_detach_node(dn); > @@ -593,8 +601,9 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index) > > pr_warn("Failed to detach CPU %s, rc: %d", dn->name, rc); > > - rc = dlpar_acquire_drc(drc_index); > - if (!rc) > + if (release_drc) > + rc = dlpar_acquire_drc(drc_index); > + if (!release_drc || !rc) > dlpar_online_cpu(dn); This is likely wrong. At this point you're in a if (rc) so rc is already non-zero. If release_drc is false this checks an invalid rc state. -Nathan > > return saved_rc; > @@ -622,7 +631,7 @@ static struct device_node *cpu_drc_index_to_dn(u32 drc_index) > return dn; > } > > -static int dlpar_cpu_remove_by_index(u32 drc_index) > +static int dlpar_cpu_remove_by_index(u32 drc_index, bool release_drc) > { > struct device_node *dn; > int rc; > @@ -634,7 +643,7 @@ static int dlpar_cpu_remove_by_index(u32 drc_index) > return -ENODEV; > } > > - rc = dlpar_cpu_remove(dn, drc_index); > + rc = dlpar_cpu_remove(dn, drc_index, release_drc); > of_node_put(dn); > return rc; > } > @@ -699,7 +708,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove) > } > > for (i = 0; i < cpus_to_remove; i++) { > - rc = dlpar_cpu_remove_by_index(cpu_drcs[i]); > + rc = dlpar_cpu_remove_by_index(cpu_drcs[i], true); > if (rc) > break; > > @@ -710,7 +719,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove) > pr_warn("CPU hot-remove failed, adding back removed CPUs\n"); > > for (i = 0; i < cpus_removed; i++) > - dlpar_cpu_add(cpu_drcs[i]); > + dlpar_cpu_add(cpu_drcs[i], true); > > rc = -EINVAL; > } else { > @@ -780,7 +789,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add) > } > > for (i = 0; i < cpus_to_add; i++) { > - rc = dlpar_cpu_add(cpu_drcs[i]); > + rc = dlpar_cpu_add(cpu_drcs[i], true); > if (rc) > break; > > @@ -791,7 +800,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add) > pr_warn("CPU hot-add failed, removing any added CPUs\n"); > > for (i = 0; i < cpus_added; i++) > - dlpar_cpu_remove_by_index(cpu_drcs[i]); > + dlpar_cpu_remove_by_index(cpu_drcs[i], true); > > rc = -EINVAL; > } else { > @@ -817,7 +826,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog) > if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) > rc = dlpar_cpu_remove_by_count(count); > else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) > - rc = dlpar_cpu_remove_by_index(drc_index); > + rc = dlpar_cpu_remove_by_index(drc_index, true); > else > rc = -EINVAL; > break; > @@ -825,7 +834,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog) > if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) > rc = dlpar_cpu_add_by_count(count); > else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) > - rc = dlpar_cpu_add(drc_index); > + rc = dlpar_cpu_add(drc_index, true); > else > rc = -EINVAL; > break; > @@ -850,7 +859,7 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count) > if (rc) > return -EINVAL; > > - rc = dlpar_cpu_add(drc_index); > + rc = dlpar_cpu_add(drc_index, true); > > return rc ? rc : count; > } > @@ -871,7 +880,7 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count) > return -EINVAL; > } > > - rc = dlpar_cpu_remove(dn, drc_index); > + rc = dlpar_cpu_remove(dn, drc_index, true); > of_node_put(dn); > > return rc ? rc : count; >