Re: [PATCH v7 1/2] Add xpread() and xpwrite()

diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index b9f6e12..1bac0f5 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c

@@ -542,7 +542,7 @@ static void *unpack_data(struct object_entry *obj,
 
 	do {
 		ssize_t n = (len < 64*1024) ? len : 64*1024;
-		n = pread(pack_fd, inbuf, n, from);
+		n = xpread(pack_fd, inbuf, n, from);
 		if (n < 0)
 			die_errno(_("cannot pread pack file"));
 		if (!n)

diff --git a/compat/mmap.c b/compat/mmap.c
index c9d46d1..7f662fe 100644
--- a/compat/mmap.c
+++ b/compat/mmap.c

@@ -14,7 +14,7 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 	}
 
 	while (n < length) {
-		ssize_t count = pread(fd, (char *)start + n, length - n, offset + n);
+		ssize_t count = xpread(fd, (char *)start + n, length - n, offset + n);
 
 		if (count == 0) {
 			memset((char *)start+n, 0, length-n);

@@ -22,8 +22,6 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 		}
 
 		if (count < 0) {
-			if (errno == EAGAIN || errno == EINTR)
-				continue;
 			free(start);
 			errno = EACCES;
 			return MAP_FAILED;

diff --git a/wrapper.c b/wrapper.c
index 0cc5636..25b7419 100644
--- a/wrapper.c
+++ b/wrapper.c

@@ -174,6 +174,42 @@ ssize_t xwrite(int fd, const void *buf, size_t len)
 	}
 }
 
+/*
+ * xpread() is the same as pread(), but it automatically restarts pread()
+ * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
+ * NOT GUARANTEE that "len" bytes is read even if the data is available.
+ */
+ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
+{
+	ssize_t nr;
+	if (len > MAX_IO_SIZE)
+	    len = MAX_IO_SIZE;
+	while (1) {
+		nr = pread(fd, buf, len, offset);
+		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
+			continue;
+		return nr;
+	}
+}