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, 157 insertions, 0 deletions

diff --git a/block/partitions/mac.c b/block/partitions/mac.c
new file mode 100644
index 000000000..df03ca428
--- /dev/null
+++ b/block/partitions/mac.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  fs/partitions/mac.c
+ *
+ *  Code extracted from drivers/block/genhd.c
+ *  Copyright (C) 1991-1998  Linus Torvalds
+ *  Re-organised Feb 1998 Russell King
+ */
+
+#include <linux/ctype.h>
+#include "check.h"
+#include "mac.h"
+
+#ifdef CONFIG_PPC_PMAC
+#include <asm/machdep.h>
+extern void note_bootable_part(dev_t dev, int part, int goodness);
+#endif
+
+/*
+ * Code to understand MacOS partition tables.
+ */
+
+#ifdef CONFIG_PPC_PMAC
+static inline void mac_fix_string(char *stg, int len)
+{
+	int i;
+
+	for (i = len - 1; i >= 0 && stg[i] == ' '; i--)
+		stg[i] = 0;
+}
+#endif
+
+int mac_partition(struct parsed_partitions *state)
+{
+	Sector sect;
+	unsigned char *data;
+	int slot, blocks_in_map;
+	unsigned secsize, datasize, partoffset;
+#ifdef CONFIG_PPC_PMAC
+	int found_root = 0;
+	int found_root_goodness = 0;
+#endif
+	struct mac_partition *part;
+	struct mac_driver_desc *md;
+
+	/* Get 0th block and look at the first partition map entry. */
+	md = read_part_sector(state, 0, &sect);
+	if (!md)
+		return -1;
+	if (be16_to_cpu(md->signature) != MAC_DRIVER_MAGIC) {
+		put_dev_sector(sect);
+		return 0;
+	}
+	secsize = be16_to_cpu(md->block_size);
+	put_dev_sector(sect);
+
+	/*
+	 * If the "block size" is not a power of 2, things get weird - we might
+	 * end up with a partition straddling a sector boundary, so we wouldn't
+	 * be able to read a partition entry with read_part_sector().
+	 * Real block sizes are probably (?) powers of two, so just require
+	 * that.
+	 */
+	if (!is_power_of_2(secsize))
+		return -1;
+	datasize = round_down(secsize, 512);
+	data = read_part_sector(state, datasize / 512, &sect);
+	if (!data)
+		return -1;
+	partoffset = secsize % 512;
+	if (partoffset + sizeof(*part) > datasize) {
+		put_dev_sector(sect);
+		return -1;
+	}
+	part = (struct mac_partition *) (data + partoffset);
+	if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) {
+		put_dev_sector(sect);
+		return 0;		/* not a MacOS disk */
+	}
+	blocks_in_map = be32_to_cpu(part->map_count);
+	if (blocks_in_map < 0 || blocks_in_map >= DISK_MAX_PARTS) {
+		put_dev_sector(sect);
+		return 0;
+	}
+
+	if (blocks_in_map >= state->limit)
+		blocks_in_map = state->limit - 1;
+
+	seq_buf_puts(&state->pp_buf, " [mac]");
+	for (slot = 1; slot <= blocks_in_map; ++slot) {
+		int pos = slot * secsize;
+		put_dev_sector(sect);
+		data = read_part_sector(state, pos/512, &sect);
+		if (!data)
+			return -1;
+		part = (struct mac_partition *) (data + pos%512);
+		if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC)
+			break;
+		put_partition(state, slot,
+			be32_to_cpu(part->start_block) * (secsize/512),
+			be32_to_cpu(part->block_count) * (secsize/512));
+
+		if (!strncasecmp(part->type, "Linux_RAID", 10))
+			state->parts[slot].flags = ADDPART_FLAG_RAID;
+#ifdef CONFIG_PPC_PMAC
+		/*
+		 * If this is the first bootable partition, tell the
+		 * setup code, in case it wants to make this the root.
+		 */
+		if (machine_is(powermac)) {
+			int goodness = 0;
+
+			mac_fix_string(part->processor, 16);
+			mac_fix_string(part->name, 32);
+			mac_fix_string(part->type, 32);					
+		    
+			if ((be32_to_cpu(part->status) & MAC_STATUS_BOOTABLE)
+			    && strcasecmp(part->processor, "powerpc") == 0)
+				goodness++;
+
+			if (strcasecmp(part->type, "Apple_UNIX_SVR2") == 0
+			    || (strncasecmp(part->type, "Linux", 5) == 0
+			        && strcasecmp(part->type, "Linux_swap") != 0)) {
+				int i, l;
+
+				goodness++;
+				l = strnlen(part->name, sizeof(part->name));
+				if (strncmp(part->name, "/", sizeof(part->name)) == 0)
+					goodness++;
+				for (i = 0; i <= l - 4; ++i) {
+					if (strncasecmp(part->name + i, "root",
+						     4) == 0) {
+						goodness += 2;
+						break;
+					}
+				}
+				if (strncasecmp(part->name, "swap", 4) == 0)
+					goodness--;
+			}
+
+			if (goodness > found_root_goodness) {
+				found_root = slot;
+				found_root_goodness = goodness;
+			}
+		}
+#endif /* CONFIG_PPC_PMAC */
+	}
+#ifdef CONFIG_PPC_PMAC
+	if (found_root_goodness)
+		note_bootable_part(state->disk->part0->bd_dev, found_root,
+				   found_root_goodness);
+#endif
+
+	put_dev_sector(sect);
+	seq_buf_puts(&state->pp_buf, "\n");
+	return 1;
+}