Merge tag 'mm-nonmm-stable-2025-04-02-22-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more non-MM updates from Andrew Morton:
 "One bugfix and a couple of small late-arriving updates"

* tag 'mm-nonmm-stable-2025-04-02-22-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  lib: scatterlist: fix sg_split_phys to preserve original scatterlist offsets
  lib/sort.c: add _nonatomic() variants with cond_resched()
  mailmap: add an entry for Nicolas Schier

Author: torvalds

.mailmap

@@ -549,6 +549,8 @@ Nicolas Pitre <nico@fluxnic.net> <nicolas.pitre@linaro.org>
 Nicolas Pitre <nico@fluxnic.net> <nico@linaro.org>
 Nicolas Saenz Julienne <nsaenz@kernel.org> <nsaenzjulienne@suse.de>
 Nicolas Saenz Julienne <nsaenz@kernel.org> <nsaenzjulienne@suse.com>
+Nicolas Schier <nicolas.schier@linux.dev> <n.schier@avm.de>
+Nicolas Schier <nicolas.schier@linux.dev> <nicolas@fjasle.eu>
 Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
 Nikolay Aleksandrov <razor@blackwall.org> <naleksan@redhat.com>
 Nikolay Aleksandrov <razor@blackwall.org> <nikolay@redhat.com>

include/linux/sort.h

@@ -13,4 +13,15 @@ void sort(void *base, size_t num, size_t size,
 	  cmp_func_t cmp_func,
 	  swap_func_t swap_func);
 
+/* Versions that periodically call cond_resched(): */
+
+void sort_r_nonatomic(void *base, size_t num, size_t size,
+		      cmp_r_func_t cmp_func,
+		      swap_r_func_t swap_func,
+		      const void *priv);
+
+void sort_nonatomic(void *base, size_t num, size_t size,
+		    cmp_func_t cmp_func,
+		    swap_func_t swap_func);
+
 #endif

lib/sg_split.c

@@ -88,8 +88,6 @@ static void sg_split_phys(struct sg_splitter *splitters, const int nb_splits)
 			if (!j) {
 				out_sg->offset += split->skip_sg0;
 				out_sg->length -= split->skip_sg0;
-			} else {
-				out_sg->offset = 0;
 			}
 			sg_dma_address(out_sg) = 0;
 			sg_dma_len(out_sg) = 0;

lib/sort.c

@@ -186,36 +186,13 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
 	return i / 2;
 }
 
-/**
- * sort_r - sort an array of elements
- * @base: pointer to data to sort
- * @num: number of elements
- * @size: size of each element
- * @cmp_func: pointer to comparison function
- * @swap_func: pointer to swap function or NULL
- * @priv: third argument passed to comparison function
- *
- * This function does a heapsort on the given array.  You may provide
- * a swap_func function if you need to do something more than a memory
- * copy (e.g. fix up pointers or auxiliary data), but the built-in swap
- * avoids a slow retpoline and so is significantly faster.
- *
- * The comparison function must adhere to specific mathematical
- * properties to ensure correct and stable sorting:
- * - Antisymmetry: cmp_func(a, b) must return the opposite sign of
- * cmp_func(b, a).
- * - Transitivity: if cmp_func(a, b) <= 0 and cmp_func(b, c) <= 0, then
- * cmp_func(a, c) <= 0.
- *
- * Sorting time is O(n log n) both on average and worst-case. While
- * quicksort is slightly faster on average, it suffers from exploitable
- * O(n*n) worst-case behavior and extra memory requirements that make
- * it less suitable for kernel use.
- */
-void sort_r(void *base, size_t num, size_t size,
-	    cmp_r_func_t cmp_func,
-	    swap_r_func_t swap_func,
-	    const void *priv)
+#include <linux/sched.h>
+
+static void __sort_r(void *base, size_t num, size_t size,
+		     cmp_r_func_t cmp_func,
+		     swap_r_func_t swap_func,
+		     const void *priv,
+		     bool may_schedule)
 {
 	/* pre-scale counters for performance */
 	size_t n = num * size, a = (num/2) * size;
@@ -286,15 +263,73 @@ void sort_r(void *base, size_t num, size_t size,
 			b = parent(b, lsbit, size);
 			do_swap(base + b, base + c, size, swap_func, priv);
 		}
+
+		if (may_schedule)
+			cond_resched();
 	}
 
 	n -= size;
 	do_swap(base, base + n, size, swap_func, priv);
 	if (n == size * 2 && do_cmp(base, base + size, cmp_func, priv) > 0)
 		do_swap(base, base + size, size, swap_func, priv);
 }
+
+/**
+ * sort_r - sort an array of elements
+ * @base: pointer to data to sort
+ * @num: number of elements
+ * @size: size of each element
+ * @cmp_func: pointer to comparison function
+ * @swap_func: pointer to swap function or NULL
+ * @priv: third argument passed to comparison function
+ *
+ * This function does a heapsort on the given array.  You may provide
+ * a swap_func function if you need to do something more than a memory
+ * copy (e.g. fix up pointers or auxiliary data), but the built-in swap
+ * avoids a slow retpoline and so is significantly faster.
+ *
+ * The comparison function must adhere to specific mathematical
+ * properties to ensure correct and stable sorting:
+ * - Antisymmetry: cmp_func(a, b) must return the opposite sign of
+ * cmp_func(b, a).
+ * - Transitivity: if cmp_func(a, b) <= 0 and cmp_func(b, c) <= 0, then
+ * cmp_func(a, c) <= 0.
+ *
+ * Sorting time is O(n log n) both on average and worst-case. While
+ * quicksort is slightly faster on average, it suffers from exploitable
+ * O(n*n) worst-case behavior and extra memory requirements that make
+ * it less suitable for kernel use.
+ */
+void sort_r(void *base, size_t num, size_t size,
+	    cmp_r_func_t cmp_func,
+	    swap_r_func_t swap_func,
+	    const void *priv)
+{
+	__sort_r(base, num, size, cmp_func, swap_func, priv, false);
+}
 EXPORT_SYMBOL(sort_r);
 
+/**
+ * sort_r_nonatomic - sort an array of elements, with cond_resched
+ * @base: pointer to data to sort
+ * @num: number of elements
+ * @size: size of each element
+ * @cmp_func: pointer to comparison function
+ * @swap_func: pointer to swap function or NULL
+ * @priv: third argument passed to comparison function
+ *
+ * Same as sort_r, but preferred for larger arrays as it does a periodic
+ * cond_resched().
+ */
+void sort_r_nonatomic(void *base, size_t num, size_t size,
+		      cmp_r_func_t cmp_func,
+		      swap_r_func_t swap_func,
+		      const void *priv)
+{
+	__sort_r(base, num, size, cmp_func, swap_func, priv, true);
+}
+EXPORT_SYMBOL(sort_r_nonatomic);
+
 void sort(void *base, size_t num, size_t size,
 	  cmp_func_t cmp_func,
 	  swap_func_t swap_func)
@@ -304,6 +339,19 @@ void sort(void *base, size_t num, size_t size,
 		.swap = swap_func,
 	};
 
-	return sort_r(base, num, size, _CMP_WRAPPER, SWAP_WRAPPER, &w);
+	return __sort_r(base, num, size, _CMP_WRAPPER, SWAP_WRAPPER, &w, false);
 }
 EXPORT_SYMBOL(sort);
+
+void sort_nonatomic(void *base, size_t num, size_t size,
+		    cmp_func_t cmp_func,
+		    swap_func_t swap_func)
+{
+	struct wrapper w = {
+		.cmp  = cmp_func,
+		.swap = swap_func,
+	};
+
+	return __sort_r(base, num, size, _CMP_WRAPPER, SWAP_WRAPPER, &w, true);
+}
+EXPORT_SYMBOL(sort_nonatomic);