iio: proximity: isl29501: Fix return type of isl29501_register_writegrafted

isl29501_register_write() was returning a u32 instead of an int.
Since the function returns negative error codes (such as -ERANGE or
return values from i2c_smbus_write_byte_data()), returning an unsigned
integer type prevents callers from correctly checking for negative error
conditions.

Fix this by changing the function return type from u32 to int.

This was found through manual code review.

Fixes: 1c28799257bc ("iio: light: isl29501: Add support for the ISL29501 ToF sensor.")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 217 insertions, 0 deletions

diff --git a/lib/region_alloc_benchmark.c b/lib/region_alloc_benchmark.c
new file mode 100644
index 000000000..e88b4cf55
--- /dev/null
+++ b/lib/region_alloc_benchmark.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Benchmark bitmap, IDA and Maple Tree allocation of variable-sized regions. */
+
+#include <linux/bitmap.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/maple_tree.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/xarray.h>
+
+#define REGION_MAX_SIZE	32
+
+static unsigned long *bitmap __initdata;
+/* One more request guarantees that even an all-ones trace reaches ENOSPC. */
+static u8 *reg_sz __initdata;
+static unsigned long *reg_idx __initdata;
+static unsigned long capacities[64] = { 1000000, 100000, 10000, 1000, 100, 10 };
+static unsigned int cap_cnt = 6;
+
+module_param_array(capacities, ulong, &cap_cnt, 0400);
+MODULE_PARM_DESC(capacities, "Region capacities to benchmark");
+
+static unsigned long __init benchmark_bitmap(unsigned long cap)
+{
+	unsigned long cnt, idx;
+	ktime_t alloc_time, free_time;
+	size_t sz;
+
+	bitmap_zero(bitmap, cap);
+	alloc_time = ktime_get();
+	for (cnt = 0; cnt <= cap; cnt++) {
+		idx = bitmap_find_next_zero_area(bitmap, cap, 0, reg_sz[cnt], 0);
+		if (idx >= cap)
+			break;
+
+		reg_idx[cnt] = idx;
+		bitmap_set(bitmap, idx, reg_sz[cnt]);
+	}
+	alloc_time = ktime_get() - alloc_time;
+
+	idx = cnt;
+
+	free_time = ktime_get();
+	while (idx--)
+		bitmap_clear(bitmap, reg_idx[idx], reg_sz[idx]);
+	free_time = ktime_get() - free_time;
+
+	WARN_ON(!bitmap_empty(bitmap, cap));
+
+	sz = BITS_TO_LONGS(cap) * sizeof(unsigned long);
+	pr_err("Bitmap  %12llu  %12llu  %8lu  %8lu  %10zu\n",
+	       alloc_time, free_time, cnt, cap, sz);
+
+	return cnt;
+}
+
+static size_t __init ida_size(unsigned long nr_ids)
+{
+	unsigned long entries = DIV_ROUND_UP(nr_ids, IDA_BITMAP_BITS);
+	unsigned long bitmaps = nr_ids / IDA_BITMAP_BITS;
+	unsigned long nodes = 0;
+
+	if (nr_ids % IDA_BITMAP_BITS > BITS_PER_XA_VALUE)
+		bitmaps++;
+
+	while (entries > 1) {
+		entries = DIV_ROUND_UP(entries, XA_CHUNK_SIZE);
+		nodes += entries;
+	}
+
+	return sizeof(struct ida) +
+		bitmaps * sizeof(struct ida_bitmap) +
+		nodes   * sizeof(struct xa_node);
+}
+
+static unsigned long __init benchmark_ida(unsigned long cap)
+{
+	struct ida ida = IDA_INIT(ida);
+	unsigned long cnt, idx, off, nr_ids = 0;
+	ktime_t alloc_time, free_time;
+	int id = -ENOSPC;
+
+	alloc_time = ktime_get();
+	for (cnt = 0; cnt <= cap; cnt++) {
+		for (off = 0; off < reg_sz[cnt]; off++) {
+			id = ida_alloc_max(&ida, cap - 1, GFP_KERNEL);
+			if (id < 0)
+				break;
+
+			if (!off)
+				reg_idx[cnt] = id;
+		}
+		if (id < 0) {
+			while (off--)
+				ida_free(&ida, reg_idx[cnt] + off);
+			break;
+		}
+		WARN_ON(id != reg_idx[cnt] + reg_sz[cnt] - 1);
+		nr_ids += reg_sz[cnt];
+	}
+	alloc_time = ktime_get() - alloc_time;
+
+	WARN_ON(id != -ENOSPC);
+
+	idx = cnt;
+
+	free_time = ktime_get();
+	while (idx--) {
+		for (off = 0; off < reg_sz[idx]; off++)
+			ida_free(&ida, reg_idx[idx] + off);
+	}
+	free_time = ktime_get() - free_time;
+
+	WARN_ON(!ida_is_empty(&ida));
+
+	pr_err("IDA     %12llu  %12llu  %8lu  %8lu  %10zu\n",
+	       alloc_time, free_time, cnt, cap, ida_size(nr_ids));
+
+	ida_destroy(&ida);
+	return cnt;
+}
+
+static unsigned long __init benchmark_maple_tree(unsigned long cap)
+{
+	struct maple_tree mt = MTREE_INIT(mt, MT_FLAGS_ALLOC_RANGE);
+	unsigned long cnt, idx;
+	ktime_t alloc_time, free_time;
+	size_t sz;
+	int ret;
+
+	alloc_time = ktime_get();
+	for (cnt = 0; cnt <= cap; cnt++) {
+		ret = mtree_alloc_range(&mt, &idx, xa_mk_value(cnt + 1),
+					reg_sz[cnt], 0, cap - 1, GFP_KERNEL);
+		if (ret)
+			break;
+
+		reg_idx[cnt] = idx;
+	}
+	alloc_time = ktime_get() - alloc_time;
+
+	WARN_ON(ret != -EBUSY);
+
+	idx = cnt;
+
+	free_time = ktime_get();
+	while (idx--)
+		mtree_erase(&mt, reg_idx[idx]);
+	free_time = ktime_get() - free_time;
+
+	WARN_ON(!mtree_empty(&mt));
+
+	/* Minimum storage assuming fully occupied allocation-range leaf nodes. */
+	sz = sizeof(mt) + DIV_ROUND_UP(cnt, MAPLE_ARANGE64_SLOTS) * sizeof(struct maple_node);
+	pr_err("Maple   %12llu  %12llu  %8lu  %8lu  %10zu\n",
+	       alloc_time, free_time, cnt, cap, sz);
+
+	mtree_destroy(&mt);
+	return cnt;
+}
+
+static int __init region_alloc_benchmark(void)
+{
+	unsigned long bitmap_count, ida_count, maple_count;
+	unsigned long i, max_cap = 0;
+	int ret = -ENOMEM;
+
+	for (i = 0; i < cap_cnt; i++) {
+		if (capacities[i] == 0) {
+			pr_err("capacity must be nonzero\n");
+			return -EINVAL;
+		}
+		max_cap = max(max_cap, capacities[i]);
+	}
+
+	bitmap = kvmalloc_array(BITS_TO_LONGS(max_cap), sizeof(*bitmap), GFP_KERNEL);
+	reg_sz = kvmalloc_array(max_cap + 1, sizeof(*reg_sz), GFP_KERNEL);
+	reg_idx = kvmalloc_array(max_cap, sizeof(*reg_idx), GFP_KERNEL);
+	if (!bitmap || !reg_sz || !reg_idx)
+		goto out;
+
+	pr_err("\nStart testing bitmap vs IDA vs Maple Tree region allocation\n");
+	pr_err("memory: bitmap is exact; IDA and Maple Tree are lower bounds\n");
+	pr_err("Type      alloc (ns)     free (ns)   regions  capacity  memory (B)\n");
+
+	for (i = 0; i < cap_cnt; i++) {
+		unsigned long idx, max_size;
+
+		max_size = min(REGION_MAX_SIZE, capacities[i] / 10) ? : 1;
+		for (idx = 0; idx <= capacities[i]; idx++)
+			reg_sz[idx] = get_random_u32_below(max_size) + 1;
+
+		bitmap_count = benchmark_bitmap(capacities[i]);
+		maple_count  = benchmark_maple_tree(capacities[i]);
+		ida_count    = benchmark_ida(capacities[i]);
+
+		WARN_ON(bitmap_count != ida_count);
+		WARN_ON(bitmap_count != maple_count);
+	}
+
+	/* Return an error so the benchmark can run repeatedly without rmmod. */
+	pr_info("Region allocation benchmark complete\n");
+	ret = -EAGAIN;
+out:
+	kvfree(reg_idx);
+	kvfree(reg_sz);
+	kvfree(bitmap);
+	return ret;
+}
+module_init(region_alloc_benchmark);
+
+MODULE_AUTHOR("Yury Norov <ynorov@nvidia.com>");
+MODULE_DESCRIPTION("Benchmark bitmap, IDA and Maple Tree region allocation");
+MODULE_LICENSE("GPL");