diff --git a/compat/mmap.c b/compat/mmap.c
index bb34c7e95f6..4cfaee31361 100644
--- a/compat/mmap.c
+++ b/compat/mmap.c
@@ -2,17 +2,11 @@
 
 void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
 {
-	int n = 0;
-	off_t current_offset = lseek(fd, 0, SEEK_CUR);
+	size_t n = 0;
 
 	if (start != NULL || !(flags & MAP_PRIVATE))
 		die("Invalid usage of mmap when built with NO_MMAP");
 
-	if (lseek(fd, offset, SEEK_SET) < 0) {
-		errno = EINVAL;
-		return MAP_FAILED;
-	}
-
 	start = xmalloc(length);
 	if (start == NULL) {
 		errno = ENOMEM;
@@ -20,14 +14,16 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 	}
 
 	while (n < length) {
-		int count = read(fd, start+n, length-n);
+		ssize_t count = pread(fd, (char *)start + n, length - n, offset + n);
 
 		if (count == 0) {
-			memset(start+n, 0, length-n);
+			memset((char *)start+n, 0, length-n);
 			break;
 		}
 
 		if (count < 0) {
+			if (errno == EAGAIN || errno == EINTR)
+				continue;
 			free(start);
 			errno = EACCES;
 			return MAP_FAILED;
@@ -36,11 +32,6 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 		n += count;
 	}
 
-	if (current_offset != lseek(fd, current_offset, SEEK_SET)) {
-		errno = EINVAL;
-		return MAP_FAILED;
-	}
-
 	return start;
 }