compote: basic infrastructure to allocate memory using compote

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>

3 files changed, 111 insertions, 0 deletions

diff --git a/compote-uapi.h b/compote-uapi.h
new file mode 100644
index 0000000..bbedb2a
--- /dev/null
+++ b/compote-uapi.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Jérôme Glisse <jglisse@redhat.com>
+ */
+#ifndef COMPOTE_UAPI_H
+#define COMPOTE_UAPI_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+#include <linux/irqnr.h>
+
+struct compote_ioctl_mem_alloc {
+	uint64_t		nbytes;
+	uint64_t		foffset;
+};
+
+struct compote_ioctl_mem_free {
+	uint64_t		foffset;
+};
+
+/* Expose the address space of the calling process through hmm dummy dev file */
+#define COMPOTE_IOCTL_MEM_ALLOC		_IOWR('H', 0x00, struct compote_ioctl_mem_alloc)
+#define COMPOTE_IOCTL_MEM_FREE		_IOWR('H', 0x01, struct compote_ioctl_mem_free)
+
+#endif /* COMPOTE_UAPI_H */
diff --git a/compote.c b/compote.c
index 1267118..190aff6 100644
--- a/compote.c
+++ b/compote.c
@@ -25,6 +25,7 @@
 #include <fcntl.h>
 
 #include "compote.h"
+#include "compote-uapi.h"
 
 
 int compote_context_new(compote_context_t **ctxp)
@@ -59,9 +60,65 @@ void compote_context_del(compote_context_t **ctxp)
     free(ctx);
 }
 
+int compote_context_ioctl(compote_context_t *ctx, int command, void *arg)
+{
+    do {
+        int ret;
+
+        ret = ioctl(ctx->fd, command, arg);
+        if (ret && errno != EINTR) {
+            printf("ret %d errno %d\n", ret, errno);
+            return ret;
+        }
+    } while (errno == EINTR);
+
+    return 0;
+}
+
+int compote_mo_new(compote_context_t *ctx, compote_mo_t **mop, uint64_t nbytes)
+{
+    struct compote_ioctl_mem_alloc arg;
+    compote_mo_t *mo;
+    int ret;
+
+    *mop = NULL;
+    mo = calloc(1, sizeof(*mo));
+    if (mo == NULL) {
+        return -ENOMEM;
+    }
+
+    arg.nbytes = nbytes;
+    ret = compote_context_ioctl(ctx, COMPOTE_IOCTL_MEM_ALLOC, &arg);
+    if (ret) {
+        free(mo);
+        return ret;
+    }
+
+    mo->foffset = arg.foffset;
+    mo->nbytes = nbytes;
+    *mop = mo;
+    return 0;
+}
+
+void compote_mo_del(compote_context_t *ctx, compote_mo_t **mop)
+{
+    struct compote_ioctl_mem_free arg;
+    compote_mo_t *mo = *mop;
+
+    *mop = NULL;
+    if (mo == NULL) {
+        return;
+    }
+
+    arg.foffset = mo->foffset;
+    compote_context_ioctl(ctx, COMPOTE_IOCTL_MEM_FREE, &arg);
+    free(mo);
+}
+
 int main(int argc, char *argv[])
 {
     compote_context_t *ctx;
+    compote_mo_t *mo;
     int ret;
 
     ret = compote_context_new(&ctx);
@@ -69,8 +126,14 @@ int main(int argc, char *argv[])
         return ret;
     }
 
+    ret = compote_mo_new(ctx, &mo, 64 << 10);
+    if (ret) {
+        return ret;
+    }
+
     printf("La compote c'est bon !\n");
 
+    compote_mo_del(ctx, &mo);
     compote_context_del(&ctx);
     return 0;
 }
diff --git a/compote.h b/compote.h
index f2ea929..4c5bb18 100644
--- a/compote.h
+++ b/compote.h
@@ -16,11 +16,23 @@
 #ifndef COMPOTE_H
 #define COMPOTE_H
 
+#include <stdint.h>
+
 typedef struct {
     int                         fd;
 } compote_context_t;
 
+typedef struct {
+    uint64_t                    foffset;
+    uint64_t                    nbytes;
+    void                        *ptr;
+} compote_mo_t;
+
 int compote_context_new(compote_context_t **ctxp);
 void compote_context_del(compote_context_t **ctxp);
+int compote_context_ioctl(compote_context_t *ctx, int command, void *arg);
+
+int compote_mo_new(compote_context_t *ctx, compote_mo_t **mop, uint64_t nbytes);
+void compote_mo_del(compote_context_t *ctx, compote_mo_t **mop);
 
 #endif // COMPOTE_H