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Message-ID: <158694419081.28353.17469261837051002623.tip-bot2@tip-bot2>
Date: Wed, 15 Apr 2020 09:49:50 -0000
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...e.de>,
x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: ras/core] x86/mce/amd: Cleanup threshold device remove path
The following commit has been merged into the ras/core branch of tip:
Commit-ID: f26d2580a7ddc84aa9e51e47fdbb5ad63dbee5a7
Gitweb: https://git.kernel.org/tip/f26d2580a7ddc84aa9e51e47fdbb5ad63dbee5a7
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 31 Mar 2020 10:53:18 +02:00
Committer: Borislav Petkov <bp@...e.de>
CommitterDate: Tue, 14 Apr 2020 15:49:51 +02:00
x86/mce/amd: Cleanup threshold device remove path
Pass in the bank pointer directly to the cleaning up functions,
obviating the need for per-CPU accesses. Make the clean up path
interrupt-safe by cleaning the bank pointer first so that the rest of
the teardown happens safe from the thresholding interrupt.
No functional changes.
[ bp: Write commit message and reverse bank->shared test to save an
indentation level in threshold_remove_bank(). ]
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lkml.kernel.org/r/20200403161943.1458-7-bp@alien8.de
---
arch/x86/include/asm/amd_nb.h | 1 +-
arch/x86/kernel/cpu/mce/amd.c | 79 +++++++++++++++-------------------
2 files changed, 38 insertions(+), 42 deletions(-)
diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
index c7df20e..455066a 100644
--- a/arch/x86/include/asm/amd_nb.h
+++ b/arch/x86/include/asm/amd_nb.h
@@ -57,6 +57,7 @@ struct threshold_bank {
/* initialized to the number of CPUs on the node sharing this bank */
refcount_t cpus;
+ unsigned int shared;
};
struct amd_northbridge {
diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index a33d9a1..16e7aea 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -1362,6 +1362,7 @@ static int threshold_create_bank(struct threshold_bank **bp, unsigned int cpu,
}
if (is_shared_bank(bank)) {
+ b->shared = 1;
refcount_set(&b->cpus, 1);
/* nb is already initialized, see above */
@@ -1391,21 +1392,16 @@ static void threshold_block_release(struct kobject *kobj)
kfree(to_block(kobj));
}
-static void deallocate_threshold_block(unsigned int cpu, unsigned int bank)
+static void deallocate_threshold_blocks(struct threshold_bank *bank)
{
- struct threshold_block *pos = NULL;
- struct threshold_block *tmp = NULL;
- struct threshold_bank *head = per_cpu(threshold_banks, cpu)[bank];
-
- if (!head)
- return;
+ struct threshold_block *pos, *tmp;
- list_for_each_entry_safe(pos, tmp, &head->blocks->miscj, miscj) {
+ list_for_each_entry_safe(pos, tmp, &bank->blocks->miscj, miscj) {
list_del(&pos->miscj);
kobject_put(&pos->kobj);
}
- kobject_put(&head->blocks->kobj);
+ kobject_put(&bank->blocks->kobj);
}
static void __threshold_remove_blocks(struct threshold_bank *b)
@@ -1419,57 +1415,56 @@ static void __threshold_remove_blocks(struct threshold_bank *b)
kobject_del(&pos->kobj);
}
-static void threshold_remove_bank(unsigned int cpu, int bank)
+static void threshold_remove_bank(struct threshold_bank *bank)
{
struct amd_northbridge *nb;
- struct threshold_bank *b;
- b = per_cpu(threshold_banks, cpu)[bank];
- if (!b)
- return;
+ if (!bank->blocks)
+ goto out_free;
- if (!b->blocks)
- goto free_out;
+ if (!bank->shared)
+ goto out_dealloc;
- if (is_shared_bank(bank)) {
- if (!refcount_dec_and_test(&b->cpus)) {
- __threshold_remove_blocks(b);
- per_cpu(threshold_banks, cpu)[bank] = NULL;
- return;
- } else {
- /*
- * the last CPU on this node using the shared bank is
- * going away, remove that bank now.
- */
- nb = node_to_amd_nb(amd_get_nb_id(cpu));
- nb->bank4 = NULL;
- }
+ if (!refcount_dec_and_test(&bank->cpus)) {
+ __threshold_remove_blocks(bank);
+ return;
+ } else {
+ /*
+ * The last CPU on this node using the shared bank is going
+ * away, remove that bank now.
+ */
+ nb = node_to_amd_nb(amd_get_nb_id(smp_processor_id()));
+ nb->bank4 = NULL;
}
- deallocate_threshold_block(cpu, bank);
+out_dealloc:
+ deallocate_threshold_blocks(bank);
-free_out:
- kobject_del(b->kobj);
- kobject_put(b->kobj);
- kfree(b);
- per_cpu(threshold_banks, cpu)[bank] = NULL;
+out_free:
+ kobject_put(bank->kobj);
+ kfree(bank);
}
int mce_threshold_remove_device(unsigned int cpu)
{
struct threshold_bank **bp = this_cpu_read(threshold_banks);
- unsigned int bank;
+ unsigned int bank, numbanks = this_cpu_read(mce_num_banks);
if (!bp)
return 0;
- for (bank = 0; bank < per_cpu(mce_num_banks, cpu); ++bank) {
- if (!(per_cpu(bank_map, cpu) & (1 << bank)))
- continue;
- threshold_remove_bank(cpu, bank);
- }
- /* Clear the pointer before freeing the memory */
+ /*
+ * Clear the pointer before cleaning up, so that the interrupt won't
+ * touch anything of this.
+ */
this_cpu_write(threshold_banks, NULL);
+
+ for (bank = 0; bank < numbanks; bank++) {
+ if (bp[bank]) {
+ threshold_remove_bank(bp[bank]);
+ bp[bank] = NULL;
+ }
+ }
kfree(bp);
return 0;
}
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