Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.

1 files changed, 146 insertions, 0 deletions

diff --git a/include/rdma/iba.h b/include/rdma/iba.h
new file mode 100644
index 000000000..dcae154ed
--- /dev/null
+++ b/include/rdma/iba.h
@@ -0,0 +1,146 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2020, Mellanox Technologies inc.  All rights reserved.
+ */
+#ifndef _IBA_DEFS_H_
+#define _IBA_DEFS_H_
+
+#include <linux/kernel.h>
+#include <linux/bitfield.h>
+#include <linux/unaligned.h>
+
+static inline u32 _iba_get8(const u8 *ptr)
+{
+	return *ptr;
+}
+
+static inline void _iba_set8(u8 *ptr, u32 mask, u32 prep_value)
+{
+	*ptr = (*ptr & ~mask) | prep_value;
+}
+
+static inline u16 _iba_get16(const __be16 *ptr)
+{
+	return be16_to_cpu(*ptr);
+}
+
+static inline void _iba_set16(__be16 *ptr, u16 mask, u16 prep_value)
+{
+	*ptr = cpu_to_be16((be16_to_cpu(*ptr) & ~mask) | prep_value);
+}
+
+static inline u32 _iba_get32(const __be32 *ptr)
+{
+	return be32_to_cpu(*ptr);
+}
+
+static inline void _iba_set32(__be32 *ptr, u32 mask, u32 prep_value)
+{
+	*ptr = cpu_to_be32((be32_to_cpu(*ptr) & ~mask) | prep_value);
+}
+
+static inline u64 _iba_get64(const __be64 *ptr)
+{
+	/*
+	 * The mads are constructed so that 32 bit and smaller are naturally
+	 * aligned, everything larger has a max alignment of 4 bytes.
+	 */
+	return be64_to_cpu(get_unaligned(ptr));
+}
+
+static inline void _iba_set64(__be64 *ptr, u64 mask, u64 prep_value)
+{
+	put_unaligned(cpu_to_be64((_iba_get64(ptr) & ~mask) | prep_value), ptr);
+}
+
+#define _IBA_SET(field_struct, field_offset, field_mask, num_bits, ptr, value) \
+	({                                                                     \
+		field_struct *_ptr = ptr;                                      \
+		_iba_set##num_bits((void *)_ptr + (field_offset), field_mask,  \
+				   FIELD_PREP(field_mask, value));             \
+	})
+#define IBA_SET(field, ptr, value) _IBA_SET(field, ptr, value)
+
+#define _IBA_GET_MEM_PTR(field_struct, field_offset, type, num_bits, ptr)      \
+	({                                                                     \
+		field_struct *_ptr = ptr;                                      \
+		(type *)((void *)_ptr + (field_offset));                       \
+	})
+#define IBA_GET_MEM_PTR(field, ptr) _IBA_GET_MEM_PTR(field, ptr)
+
+/* FIXME: A set should always set the entire field, meaning we should zero the trailing bytes */
+#define _IBA_SET_MEM(field_struct, field_offset, type, num_bits, ptr, in,      \
+		     bytes)                                                    \
+	({                                                                     \
+		const type *_in_ptr = in;                                      \
+		WARN_ON(bytes * 8 > num_bits);                                 \
+		if (in && bytes)                                               \
+			memcpy(_IBA_GET_MEM_PTR(field_struct, field_offset,    \
+						type, num_bits, ptr),          \
+			       _in_ptr, bytes);                                \
+	})
+#define IBA_SET_MEM(field, ptr, in, bytes) _IBA_SET_MEM(field, ptr, in, bytes)
+
+#define _IBA_GET(field_struct, field_offset, field_mask, num_bits, ptr)        \
+	({                                                                     \
+		const field_struct *_ptr = ptr;                                \
+		(u##num_bits) FIELD_GET(                                       \
+			field_mask, _iba_get##num_bits((const void *)_ptr +    \
+						       (field_offset)));       \
+	})
+#define IBA_GET(field, ptr) _IBA_GET(field, ptr)
+
+#define _IBA_GET_MEM(field_struct, field_offset, type, num_bits, ptr, out,     \
+		     bytes)                                                    \
+	({                                                                     \
+		type *_out_ptr = out;                                          \
+		WARN_ON(bytes * 8 > num_bits);                                 \
+		if (out && bytes)                                              \
+			memcpy(_out_ptr,                                       \
+			       _IBA_GET_MEM_PTR(field_struct, field_offset,    \
+						type, num_bits, ptr),          \
+			       bytes);                                         \
+	})
+#define IBA_GET_MEM(field, ptr, out, bytes) _IBA_GET_MEM(field, ptr, out, bytes)
+
+/*
+ * The generated list becomes the parameters to the macros, the order is:
+ *  - struct this applies to
+ *  - starting offset of the max
+ *  - GENMASK or GENMASK_ULL in CPU order
+ *  - The width of data the mask operations should work on, in bits
+ */
+
+/*
+ * Extraction using a tabular description like table 106. bit_offset is from
+ * the Byte[Bit] notation.
+ */
+#define IBA_FIELD_BLOC(field_struct, byte_offset, bit_offset, num_bits)        \
+	field_struct, byte_offset,                                             \
+		GENMASK(7 - (bit_offset), 7 - (bit_offset) - (num_bits - 1)),  \
+		8
+#define IBA_FIELD8_LOC(field_struct, byte_offset, num_bits)                    \
+	IBA_FIELD_BLOC(field_struct, byte_offset, 0, num_bits)
+
+#define IBA_FIELD16_LOC(field_struct, byte_offset, num_bits)                   \
+	field_struct, (byte_offset)&0xFFFE,                                    \
+		GENMASK(15 - (((byte_offset) % 2) * 8),                        \
+			15 - (((byte_offset) % 2) * 8) - (num_bits - 1)),      \
+		16
+
+#define IBA_FIELD32_LOC(field_struct, byte_offset, num_bits)                   \
+	field_struct, (byte_offset)&0xFFFC,                                    \
+		GENMASK(31 - (((byte_offset) % 4) * 8),                        \
+			31 - (((byte_offset) % 4) * 8) - (num_bits - 1)),      \
+		32
+
+#define IBA_FIELD64_LOC(field_struct, byte_offset)                             \
+	field_struct, byte_offset, GENMASK_ULL(63, 0), 64
+/*
+ * In IBTA spec, everything that is more than 64bits is multiple
+ * of bytes without leftover bits.
+ */
+#define IBA_FIELD_MLOC(field_struct, byte_offset, num_bits, type)              \
+	field_struct, byte_offset, type, num_bits
+
+#endif /* _IBA_DEFS_H_ */