There are currently two users, and lib.h is included everywhere.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Anthony PERARD <anthony.perard@vates.tech>
CC: Michal Orzel <michal.orzel@amd.com>
CC: Jan Beulich <jbeulich@suse.com>
CC: Julien Grall <julien@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
CC: Bertrand Marquis <bertrand.marquis@arm.com>

This will marginally improve compile times, but mostly it's about splitting up
lib.h
---
 xen/arch/arm/io.c             |  1 +
 xen/arch/arm/vgic/vgic-mmio.c |  1 +
 xen/include/xen/bsearch.h     | 50 +++++++++++++++++++++++++++++++++++
 xen/include/xen/lib.h         | 43 ------------------------------
 4 files changed, 52 insertions(+), 43 deletions(-)
 create mode 100644 xen/include/xen/bsearch.h

diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c
index 96c740d5636c..653428e16c1f 100644
--- a/xen/arch/arm/io.c
+++ b/xen/arch/arm/io.c
@@ -7,6 +7,7 @@
  * Copyright (c) 2011 Citrix Systems.
  */
 
+#include <xen/bsearch.h>
 #include <xen/ioreq.h>
 #include <xen/lib.h>
 #include <xen/spinlock.h>
diff --git a/xen/arch/arm/vgic/vgic-mmio.c b/xen/arch/arm/vgic/vgic-mmio.c
index bd4caf7fc326..4ad350c21c8b 100644
--- a/xen/arch/arm/vgic/vgic-mmio.c
+++ b/xen/arch/arm/vgic/vgic-mmio.c
@@ -13,6 +13,7 @@
  */
 
 #include <xen/bitops.h>
+#include <xen/bsearch.h>
 #include <xen/lib.h>
 #include <xen/sched.h>
 #include <asm/new_vgic.h>
diff --git a/xen/include/xen/bsearch.h b/xen/include/xen/bsearch.h
new file mode 100644
index 000000000000..544fe83e2cfc
--- /dev/null
+++ b/xen/include/xen/bsearch.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef XEN_BSEARCH_H
+#define XEN_BSEARCH_H
+
+#include <xen/types.h>
+
+/*
+ * bsearch - binary search an array of elements
+ * @key: pointer to item being searched for
+ * @base: pointer to first element to search
+ * @num: number of elements
+ * @size: size of each element
+ * @cmp: pointer to comparison function
+ *
+ * This function does a binary search on the given array.  The
+ * contents of the array should already be in ascending sorted order
+ * under the provided comparison function.
+ *
+ * Note that the key need not have the same type as the elements in
+ * the array, e.g. key could be a string and the comparison function
+ * could compare the string with the struct's name field.  However, if
+ * the key and elements in the array are of the same type, you can use
+ * the same comparison function for both sort() and bsearch().
+ */
+#ifndef BSEARCH_IMPLEMENTATION
+extern gnu_inline
+#endif
+void *bsearch(const void *key, const void *base, size_t num, size_t size,
+              int (*cmp)(const void *key, const void *elt))
+{
+    size_t start = 0, end = num;
+    int result;
+
+    while ( start < end )
+    {
+        size_t mid = start + (end - start) / 2;
+
+        result = cmp(key, base + mid * size);
+        if ( result < 0 )
+            end = mid;
+        else if ( result > 0 )
+            start = mid + 1;
+        else
+            return (void *)base + mid * size;
+    }
+
+    return NULL;
+}
+
+#endif /* XEN_BSEARCH_H */
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
index 130f96791f75..7060b5d5b658 100644
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -159,49 +159,6 @@ void cf_check dump_execstate(const struct cpu_user_regs *regs);
 
 void init_constructors(void);
 
-/*
- * bsearch - binary search an array of elements
- * @key: pointer to item being searched for
- * @base: pointer to first element to search
- * @num: number of elements
- * @size: size of each element
- * @cmp: pointer to comparison function
- *
- * This function does a binary search on the given array.  The
- * contents of the array should already be in ascending sorted order
- * under the provided comparison function.
- *
- * Note that the key need not have the same type as the elements in
- * the array, e.g. key could be a string and the comparison function
- * could compare the string with the struct's name field.  However, if
- * the key and elements in the array are of the same type, you can use
- * the same comparison function for both sort() and bsearch().
- */
-#ifndef BSEARCH_IMPLEMENTATION
-extern gnu_inline
-#endif
-void *bsearch(const void *key, const void *base, size_t num, size_t size,
-              int (*cmp)(const void *key, const void *elt))
-{
-    size_t start = 0, end = num;
-    int result;
-
-    while ( start < end )
-    {
-        size_t mid = start + (end - start) / 2;
-
-        result = cmp(key, base + mid * size);
-        if ( result < 0 )
-            end = mid;
-        else if ( result > 0 )
-            start = mid + 1;
-        else
-            return (void *)base + mid * size;
-    }
-
-    return NULL;
-}
-
 #endif /* __ASSEMBLY__ */
 
 #endif /* __LIB_H__ */
-- 
2.39.5

Hi Andrew,

On 25/02/2025 22:20, Andrew Cooper wrote:
> There are currently two users, and lib.h is included everywhere.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall

On 25/02/2025 10:38 pm, Julien Grall wrote:
> Hi Andrew,
>
> On 25/02/2025 22:20, Andrew Cooper wrote:
>> There are currently two users, and lib.h is included everywhere.
>>
>> No functional change.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>
> Acked-by: Julien Grall <jgrall@amazon.com>

Thanks.

Funnily enough, there's a hunk missing.

diff --git a/xen/lib/bsearch.c b/xen/lib/bsearch.c
index 149f7feafd1f..9973117d1d8e 100644
--- a/xen/lib/bsearch.c
+++ b/xen/lib/bsearch.c
@@ -10,4 +10,4 @@
  */
 
 #define BSEARCH_IMPLEMENTATION
-#include <xen/lib.h>
+#include <xen/bsearch.h>


Nothing anywhere in CI notices, because not even ARM emits a library
call, so the fact that bsearch.o is empty when it's discarded by the
linker for not being used, is incidental.

I cannot think of any good way to fix this pattern.  Not even adding a
self-test, because we intentionally write those in a way so they get
dropped if the library function as a whole isn't referenced.

Given that we've got this pattern exactly twice (this, and SORT), I
think we just need to stay vigilant.

~Andrew