Merge tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs percpu counter fixes from Darrick Wong:
 "We discovered a filesystem summary counter corruption problem that was
  traced to cpu hot-remove racing with the call to percpu_counter_sum
  that sets the free block count in the superblock when writing it to
  disk. The root cause is that percpu_counter_sum doesn't cull from
  dying cpus and hence misses those counter values if the cpu shutdown
  hooks have not yet run to merge the values.

  I'm hoping this is a fairly painless fix to the problem, since the
  dying cpu mask should generally be empty. It's been in for-next for a
  week without any complaints from the bots.

   - Fix a race in the percpu counters summation code where the
     summation failed to add in the values for any CPUs that were dying
     but not yet dead. This fixes some minor discrepancies and incorrect
     assertions when running generic/650"

* tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  pcpcntr: remove percpu_counter_sum_all()
  fork: remove use of percpu_counter_sum_all
  pcpcntrs: fix dying cpu summation race
  cpumask: introduce for_each_cpu_or

3 files changed, 54 insertions, 6 deletions

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index d4901ca8883c..ca736b05ec7b 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -351,6 +351,23 @@ unsigned int __pure cpumask_next_wrap(int n, const struct cpumask *mask, int sta
 	for_each_andnot_bit(cpu, cpumask_bits(mask1), cpumask_bits(mask2), small_cpumask_bits)
 
 /**
+ * for_each_cpu_or - iterate over every cpu present in either mask
+ * @cpu: the (optionally unsigned) integer iterator
+ * @mask1: the first cpumask pointer
+ * @mask2: the second cpumask pointer
+ *
+ * This saves a temporary CPU mask in many places.  It is equivalent to:
+ *	struct cpumask tmp;
+ *	cpumask_or(&tmp, &mask1, &mask2);
+ *	for_each_cpu(cpu, &tmp)
+ *		...
+ *
+ * After the loop, cpu is >= nr_cpu_ids.
+ */
+#define for_each_cpu_or(cpu, mask1, mask2)				\
+	for_each_or_bit(cpu, cpumask_bits(mask1), cpumask_bits(mask2), small_cpumask_bits)
+
+/**
  * cpumask_any_but - return a "random" in a cpumask, but not this one.
  * @mask: the cpumask to search
  * @cpu: the cpu to ignore.
diff --git a/include/linux/find.h b/include/linux/find.h
index 4647864a5ffd..5e4f39ef2e72 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -14,6 +14,8 @@ unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long
 					unsigned long nbits, unsigned long start);
 unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
 					unsigned long nbits, unsigned long start);
+unsigned long _find_next_or_bit(const unsigned long *addr1, const unsigned long *addr2,
+					unsigned long nbits, unsigned long start);
 unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
 					 unsigned long start);
 extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size);
@@ -127,6 +129,36 @@ unsigned long find_next_andnot_bit(const unsigned long *addr1,
 }
 #endif
 
+#ifndef find_next_or_bit
+/**
+ * find_next_or_bit - find the next set bit in either memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @size: The bitmap size in bits
+ * @offset: The bitnumber to start searching at
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+static inline
+unsigned long find_next_or_bit(const unsigned long *addr1,
+		const unsigned long *addr2, unsigned long size,
+		unsigned long offset)
+{
+	if (small_const_nbits(size)) {
+		unsigned long val;
+
+		if (unlikely(offset >= size))
+			return size;
+
+		val = (*addr1 | *addr2) & GENMASK(size - 1, offset);
+		return val ? __ffs(val) : size;
+	}
+
+	return _find_next_or_bit(addr1, addr2, size, offset);
+}
+#endif
+
 #ifndef find_next_zero_bit
 /**
  * find_next_zero_bit - find the next cleared bit in a memory region
@@ -536,6 +568,11 @@ unsigned long find_next_bit_le(const void *addr, unsigned
 	     (bit) = find_next_andnot_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
 	     (bit)++)
 
+#define for_each_or_bit(bit, addr1, addr2, size) \
+	for ((bit) = 0;									\
+	     (bit) = find_next_or_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
+	     (bit)++)
+
 /* same as for_each_set_bit() but use bit as value to start with */
 #define for_each_set_bit_from(bit, addr, size) \
 	for (; (bit) = find_next_bit((addr), (size), (bit)), (bit) < (size); (bit)++)
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 521a733e21a9..75b73c83bc9d 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -45,7 +45,6 @@ void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
 void percpu_counter_add_batch(struct percpu_counter *fbc, s64 amount,
 			      s32 batch);
 s64 __percpu_counter_sum(struct percpu_counter *fbc);
-s64 percpu_counter_sum_all(struct percpu_counter *fbc);
 int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch);
 void percpu_counter_sync(struct percpu_counter *fbc);
 
@@ -196,11 +195,6 @@ static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
 	return percpu_counter_read(fbc);
 }
 
-static inline s64 percpu_counter_sum_all(struct percpu_counter *fbc)
-{
-	return percpu_counter_read(fbc);
-}
-
 static inline bool percpu_counter_initialized(struct percpu_counter *fbc)
 {
 	return true;