[11/52] libfrog: add memchr_inv

Commit Message

Darrick J. Wong Dec. 23, 2024, 10:01 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Add this kernel function so we can use it in userspace.

Signed-off-by: "Darrick J. Wong" <[e-mail]>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
---
 libfrog/util.c |   14 ++++++++++++++
 libfrog/util.h |    4 ++++
 2 files changed, 18 insertions(+)

Patch

diff --git a/libfrog/util.c b/libfrog/util.c
index 8fb10cf82f5ca4..46047571a5531f 100644
--- a/libfrog/util.c
+++ b/libfrog/util.c
@@ -22,3 +22,17 @@  log2_roundup(unsigned int i)
 	}
 	return rval;
 }
+
+void *
+memchr_inv(const void *start, int c, size_t bytes)
+{
+	const unsigned char	*p = start;
+
+	while (bytes > 0) {
+		if (*p != (unsigned char)c)
+			return (void *)p;
+		bytes--;
+	}
+
+	return NULL;
+}
diff --git a/libfrog/util.h b/libfrog/util.h
index 5df95e69cd11da..8b4ee7c1333b6b 100644
--- a/libfrog/util.h
+++ b/libfrog/util.h
@@ -6,6 +6,8 @@ 
 #ifndef __LIBFROG_UTIL_H__
 #define __LIBFROG_UTIL_H__
 
+#include <sys/types.h>
+
 unsigned int	log2_roundup(unsigned int i);
 
 #define min_t(type,x,y) \
@@ -13,4 +15,6 @@  unsigned int	log2_roundup(unsigned int i);
 #define max_t(type,x,y) \
 	({ type __x = (x); type __y = (y); __x > __y ? __x: __y; })
 
+void *memchr_inv(const void *start, int c, size_t bytes);
+
 #endif /* __LIBFROG_UTIL_H__ */