vmsplice-to-user: update for real zero copy to user

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/splice.h b/splice.h
index 386da4ee88b0105fcb0aa0352d82ca0e52c39d2d..5321662662f6c5a12a23328cd1ae3780a1cf6d4d 100644 (file)
--- a/splice.h
+++ b/splice.h
@@ -34,6 +34,7 @@
                                 /* from/to, of course */
 #define SPLICE_F_MORE  (0x04)  /* expect more data */
 #define SPLICE_F_GIFT   (0x08)  /* pages passed in are a gift */
+#define SPLICE_F_UNMAP (0x10)  /* undo vmsplice map */
 
 #endif /* SPLICE_F_MOVE defined */
 

diff --git a/vmsplice-touser.c b/vmsplice-touser.c
index c085a092ba3b06d8c7a0801100f59a41dd893700..b5cc9bc3feab7a139abce9a21b19b8cc176fc5e3 100644 (file)
--- a/vmsplice-touser.c
+++ b/vmsplice-touser.c
@@ -14,16 +14,28 @@
 #include "splice.h"
 
 static int do_dump;
+static int do_ascii;
+static int do_zeromap;
 static int splice_flags;
 
-int do_vmsplice(int fd, void *buf, int len)
+static int do_vmsplice_unmap(int fd, unsigned char *buf, int len)
+{
+       struct iovec iov = {
+               .iov_base = buf,
+               .iov_len = len,
+       };
+
+       return svmsplice(fd, &iov, 1, SPLICE_F_UNMAP);
+}
+
+static int do_vmsplice(int fd, unsigned char **buf, int len)
 {
        struct pollfd pfd = { .fd = fd, .events = POLLIN, };
        struct iovec iov;
        int written;
        int ret;
 
-       iov.iov_base = buf;
+       iov.iov_base = *buf;
        iov.iov_len = len;
        ret = 0;
 
@@ -51,12 +63,14 @@ int do_vmsplice(int fd, void *buf, int len)
                }
        }
 
+       if (!*buf)
+               *buf = iov.iov_base;
        return ret;
 }
 
 static int usage(char *name)
 {
-       fprintf(stderr, "| %s [-d(ump)]\n", name);
+       fprintf(stderr, "| %s [-d(ump)] [-a(ascii)] [-m(ap)] [-z(eromap)]\n", name);
        return 1;
 }
 
@@ -64,12 +78,24 @@ static int parse_options(int argc, char *argv[])
 {
        int c, index = 1;
 
-       while ((c = getopt(argc, argv, "d")) != -1) {
+       while ((c = getopt(argc, argv, "admz")) != -1) {
                switch (c) {
+               case 'a':
+                       do_ascii = 1;
+                       index++;
+                       break;
                case 'd':
                        do_dump = 1;
                        index++;
                        break;
+               case 'm':
+                       splice_flags |= SPLICE_F_MOVE;
+                       index++;
+                       break;
+               case 'z':
+                       do_zeromap = 1;
+                       index++;
+                       break;
                default:
                        return -1;
                }
@@ -84,7 +110,14 @@ static void hexdump(unsigned char *buf, int len)
 
        for (i = 0; i < len; i++)
                printf("%02x", buf[i]);
-       printf("\n");
+}
+
+static void asciidump(unsigned char *buf, int len)
+{
+       int i;
+
+       for (i = 0; i < len; i++)
+               printf("%c", buf[i]);
 }
 
 int main(int argc, char *argv[])
@@ -98,18 +131,26 @@ int main(int argc, char *argv[])
        if (check_input_pipe())
                return usage(argv[0]);
 
-       buf = malloc(4096);
+       if (!do_zeromap) {
+               buf = malloc(4096);
+               memset(buf, 0, 4096);
+       } else
+               buf = NULL;
 
-       memset(buf, 0, 4096);
-
-       ret = do_vmsplice(STDIN_FILENO, buf, 4096);
+       ret = do_vmsplice(STDIN_FILENO, &buf, 4096);
        if (ret < 0)
                return 1;
 
-       printf("splice %d\n", ret);
-
        if (do_dump)
                hexdump(buf, ret);
+       if (do_ascii)
+               asciidump(buf, ret);
 
-       return 0;
+       if (splice_flags & SPLICE_F_MOVE) {
+               ret = do_vmsplice_unmap(STDIN_FILENO, buf, 4096);
+               if (ret < 0)
+                       perror("vmsplice");
+       }
+
+       return ret;
 }