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2023-12-11 6778948f9de86c3cfaf36725a7c87dcff9ba247f 
 kernel/drivers/base/devres.c
....@@ -11,6 +11,8 @@
1111 #include <linux/slab.h>
1212 #include <linux/percpu.h>
1313 
14
+#include <asm/sections.h>
15
+
1416 #include "base.h"
1517 
1618 struct devres_node {
....@@ -87,15 +89,23 @@
8789 	return NULL;
8890 }
8991 
92
+static bool check_dr_size(size_t size, size_t *tot_size)
93
+{
94
+	/* We must catch any near-SIZE_MAX cases that could overflow. */
95
+	if (unlikely(check_add_overflow(sizeof(struct devres),
96
+					size, tot_size)))
97
+		return false;
98
+
99
+	return true;
100
+}
101
+
90102 static __always_inline struct devres * alloc_dr(dr_release_t release,
91103 						size_t size, gfp_t gfp, int nid)
92104 {
93105 	size_t tot_size;
94106 	struct devres *dr;
95107 
96
-	/* We must catch any near-SIZE_MAX cases that could overflow. */
97
-	if (unlikely(check_add_overflow(sizeof(struct devres), size,
98
-					&tot_size)))
108
+	if (!check_dr_size(size, &tot_size))
99109 		return NULL;
100110 
101111 	dr = kmalloc_node_track_caller(tot_size, gfp, nid);
....@@ -114,6 +124,14 @@
114124 	devres_log(dev, node, "ADD");
115125 	BUG_ON(!list_empty(&node->entry));
116126 	list_add_tail(&node->entry, &dev->devres_head);
127
+}
128
+
129
+static void replace_dr(struct device *dev,
130
+		       struct devres_node *old, struct devres_node *new)
131
+{
132
+	devres_log(dev, old, "REPLACE");
133
+	BUG_ON(!list_empty(&new->entry));
134
+	list_replace(&old->entry, &new->entry);
117135 }
118136 
119137 #ifdef CONFIG_DEBUG_DEVRES
....@@ -753,9 +771,31 @@
753771 
754772 	WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
755773 			       &devres));
756
-
757774 }
758775 EXPORT_SYMBOL_GPL(devm_remove_action);
776
+
777
+/**
778
+ * devm_release_action() - release previously added custom action
779
+ * @dev: Device that owns the action
780
+ * @action: Function implementing the action
781
+ * @data: Pointer to data passed to @action implementation
782
+ *
783
+ * Releases and removes instance of @action previously added by
784
+ * devm_add_action().  Both action and data should match one of the
785
+ * existing entries.
786
+ */
787
+void devm_release_action(struct device *dev, void (*action)(void *), void *data)
788
+{
789
+	struct action_devres devres = {
790
+		.data = data,
791
+		.action = action,
792
+	};
793
+
794
+	WARN_ON(devres_release(dev, devm_action_release, devm_action_match,
795
+			       &devres));
796
+
797
+}
798
+EXPORT_SYMBOL_GPL(devm_release_action);
759799 
760800 /*
761801  * Managed kmalloc/kfree
....@@ -783,9 +823,12 @@
783823  * RETURNS:
784824  * Pointer to allocated memory on success, NULL on failure.
785825  */
786
-void * devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
826
+void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
787827 {
788828 	struct devres *dr;
829
+
830
+	if (unlikely(!size))
831
+		return ZERO_SIZE_PTR;
789832 
790833 	/* use raw alloc_dr for kmalloc caller tracing */
791834 	dr = alloc_dr(devm_kmalloc_release, size, gfp, dev_to_node(dev));
....@@ -801,6 +844,103 @@
801844 	return dr->data;
802845 }
803846 EXPORT_SYMBOL_GPL(devm_kmalloc);
847
+
848
+/**
849
+ * devm_krealloc - Resource-managed krealloc()
850
+ * @dev: Device to re-allocate memory for
851
+ * @ptr: Pointer to the memory chunk to re-allocate
852
+ * @new_size: New allocation size
853
+ * @gfp: Allocation gfp flags
854
+ *
855
+ * Managed krealloc(). Resizes the memory chunk allocated with devm_kmalloc().
856
+ * Behaves similarly to regular krealloc(): if @ptr is NULL or ZERO_SIZE_PTR,
857
+ * it's the equivalent of devm_kmalloc(). If new_size is zero, it frees the
858
+ * previously allocated memory and returns ZERO_SIZE_PTR. This function doesn't
859
+ * change the order in which the release callback for the re-alloc'ed devres
860
+ * will be called (except when falling back to devm_kmalloc() or when freeing
861
+ * resources when new_size is zero). The contents of the memory are preserved
862
+ * up to the lesser of new and old sizes.
863
+ */
864
+void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp)
865
+{
866
+	size_t total_new_size, total_old_size;
867
+	struct devres *old_dr, *new_dr;
868
+	unsigned long flags;
869
+
870
+	if (unlikely(!new_size)) {
871
+		devm_kfree(dev, ptr);
872
+		return ZERO_SIZE_PTR;
873
+	}
874
+
875
+	if (unlikely(ZERO_OR_NULL_PTR(ptr)))
876
+		return devm_kmalloc(dev, new_size, gfp);
877
+
878
+	if (WARN_ON(is_kernel_rodata((unsigned long)ptr)))
879
+		/*
880
+		 * We cannot reliably realloc a const string returned by
881
+		 * devm_kstrdup_const().
882
+		 */
883
+		return NULL;
884
+
885
+	if (!check_dr_size(new_size, &total_new_size))
886
+		return NULL;
887
+
888
+	total_old_size = ksize(container_of(ptr, struct devres, data));
889
+	if (total_old_size == 0) {
890
+		WARN(1, "Pointer doesn't point to dynamically allocated memory.");
891
+		return NULL;
892
+	}
893
+
894
+	/*
895
+	 * If new size is smaller or equal to the actual number of bytes
896
+	 * allocated previously - just return the same pointer.
897
+	 */
898
+	if (total_new_size <= total_old_size)
899
+		return ptr;
900
+
901
+	/*
902
+	 * Otherwise: allocate new, larger chunk. We need to allocate before
903
+	 * taking the lock as most probably the caller uses GFP_KERNEL.
904
+	 */
905
+	new_dr = alloc_dr(devm_kmalloc_release,
906
+			  total_new_size, gfp, dev_to_node(dev));
907
+	if (!new_dr)
908
+		return NULL;
909
+
910
+	/*
911
+	 * The spinlock protects the linked list against concurrent
912
+	 * modifications but not the resource itself.
913
+	 */
914
+	spin_lock_irqsave(&dev->devres_lock, flags);
915
+
916
+	old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr);
917
+	if (!old_dr) {
918
+		spin_unlock_irqrestore(&dev->devres_lock, flags);
919
+		kfree(new_dr);
920
+		WARN(1, "Memory chunk not managed or managed by a different device.");
921
+		return NULL;
922
+	}
923
+
924
+	replace_dr(dev, &old_dr->node, &new_dr->node);
925
+
926
+	spin_unlock_irqrestore(&dev->devres_lock, flags);
927
+
928
+	/*
929
+	 * We can copy the memory contents after releasing the lock as we're
930
+	 * no longer modyfing the list links.
931
+	 */
932
+	memcpy(new_dr->data, old_dr->data,
933
+	       total_old_size - offsetof(struct devres, data));
934
+	/*
935
+	 * Same for releasing the old devres - it's now been removed from the
936
+	 * list. This is also the reason why we must not use devm_kfree() - the
937
+	 * links are no longer valid.
938
+	 */
939
+	kfree(old_dr);
940
+
941
+	return new_dr->data;
942
+}
943
+EXPORT_SYMBOL_GPL(devm_krealloc);
804944 
805945 /**
806946  * devm_kstrdup - Allocate resource managed space and
....@@ -827,6 +967,28 @@
827967 	return buf;
828968 }
829969 EXPORT_SYMBOL_GPL(devm_kstrdup);
970
+
971
+/**
972
+ * devm_kstrdup_const - resource managed conditional string duplication
973
+ * @dev: device for which to duplicate the string
974
+ * @s: the string to duplicate
975
+ * @gfp: the GFP mask used in the kmalloc() call when allocating memory
976
+ *
977
+ * Strings allocated by devm_kstrdup_const will be automatically freed when
978
+ * the associated device is detached.
979
+ *
980
+ * RETURNS:
981
+ * Source string if it is in .rodata section otherwise it falls back to
982
+ * devm_kstrdup.
983
+ */
984
+const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
985
+{
986
+	if (is_kernel_rodata((unsigned long)s))
987
+		return s;
988
+
989
+	return devm_kstrdup(dev, s, gfp);
990
+}
991
+EXPORT_SYMBOL_GPL(devm_kstrdup_const);
830992 
831993 /**
832994  * devm_kvasprintf - Allocate resource managed space and format a string
....@@ -891,11 +1053,19 @@
8911053  *
8921054  * Free memory allocated with devm_kmalloc().
8931055  */
894
-void devm_kfree(struct device *dev, void *p)
1056
+void devm_kfree(struct device *dev, const void *p)
8951057 {
8961058 	int rc;
8971059 
898
-	rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
1060
+	/*
1061
+	 * Special cases: pointer to a string in .rodata returned by
1062
+	 * devm_kstrdup_const() or NULL/ZERO ptr.
1063
+	 */
1064
+	if (unlikely(is_kernel_rodata((unsigned long)p) || ZERO_OR_NULL_PTR(p)))
1065
+		return;
1066
+
1067
+	rc = devres_destroy(dev, devm_kmalloc_release,
1068
+			    devm_kmalloc_match, (void *)p);
8991069 	WARN_ON(rc);
9001070 }
9011071 EXPORT_SYMBOL_GPL(devm_kfree);