Add mmap ioctl to mmfs.

.gitignore

@@ -59,6 +59,7 @@ tests/getstats
 tests/getversion
 tests/lock
 tests/mmfs_basic
+tests/mmfs_mmap
 tests/mmfs_readwrite
 tests/openclose
 tests/setversion

linux-core/mmfs_drv.c

@@ -32,6 +32,8 @@
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/module.h>
+#include <linux/mman.h>
+#include <linux/pagemap.h>
 #include "mmfs.h"
 
 /** @file mmfs.c
@@ -244,6 +246,45 @@ mmfs_pread_ioctl(struct inode *inode, struct file *filp,
 	return 0;
 }
 
+/**
+ * Maps the contents of an object, returning the address it is mapped
+ * into.
+ *
+ * While the mapping holds a reference on the contents of the object, it doesn't
+ * imply a ref on the object itself.
+ */
+static int
+mmfs_mmap_ioctl(struct inode *inode, struct file *filp,
+		 unsigned int cmd, unsigned long arg)
+{
+	struct mmfs_file *mmfs_filp = filp->private_data;
+	struct mmfs_mmap_args args;
+	struct mmfs_object *obj;
+	loff_t offset;
+
+	if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
+		return -EFAULT;
+
+	obj = mmfs_object_lookup(mmfs_filp, args.handle);
+	if (obj == NULL)
+		return -EINVAL;
+
+	offset = args.offset;
+
+	down_write(&current->mm->mmap_sem);
+	args.addr = (void *)do_mmap(obj->filp, 0, args.size,
+				    PROT_READ | PROT_WRITE, MAP_SHARED,
+				    args.offset);
+	up_write(&current->mm->mmap_sem);
+
+	mmfs_object_unreference(obj);
+
+	if (copy_to_user((void __user *)arg, &args, sizeof(args)))
+		return -EFAULT;
+
+	return 0;
+}
+
 /**
  * Writes data to the object referenced by handle.
  *
@@ -297,6 +338,8 @@ mmfs_ioctl(struct inode *inode, struct file *filp,
 		return mmfs_pread_ioctl(inode, filp, cmd, arg);
 	case MMFS_IOCTL_PWRITE:
 		return mmfs_pwrite_ioctl(inode, filp, cmd, arg);
+	case MMFS_IOCTL_MMAP:
+		return mmfs_mmap_ioctl(inode, filp, cmd, arg);
 	default:
 		return -EINVAL;
 	}

tests/Makefile.am

@@ -24,7 +24,8 @@ TESTS = auth \
 	setversion \
 	updatedraw \
 	mmfs_basic \
-	mmfs_readwrite
+	mmfs_readwrite \
+	mmfs_mmap
 
 EXTRA_PROGRAMS = $(TESTS)
 CLEANFILES = $(EXTRA_PROGRAMS) $(EXTRA_LTLIBRARIES)

tests/mmfs_mmap.c

@@ -0,0 +1,129 @@
+/*
+ * Copyright © 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Eric Anholt <eric@anholt.net>
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include "mmfs.h"
+
+#define MMFS_BUFFER_SIZE 16384
+
+int do_read(int fd, int handle, void *buf, int offset, int size)
+{
+	struct mmfs_pread_args read;
+
+	/* Ensure that we don't have any convenient data in buf in case
+	 * we fail.
+	 */
+	memset(buf, 0xd0, size);
+
+	memset(&read, 0, sizeof(read));
+	read.handle = handle;
+	read.data = buf;
+	read.size = size;
+	read.offset = offset;
+
+	return ioctl(fd, MMFS_IOCTL_PREAD, &read);
+}
+
+int do_write(int fd, int handle, void *buf, int offset, int size)
+{
+	struct mmfs_pwrite_args write;
+
+	memset(&write, 0, sizeof(write));
+	write.handle = handle;
+	write.data = buf;
+	write.size = size;
+	write.offset = offset;
+
+	return ioctl(fd, MMFS_IOCTL_PWRITE, &write);
+}
+
+int main(int argc, char **argv)
+{
+	int fd;
+	struct mmfs_alloc_args alloc;
+	struct mmfs_mmap_args mmap;
+	struct mmfs_unreference_args unref;
+	uint8_t expected[MMFS_BUFFER_SIZE];
+	uint8_t buf[MMFS_BUFFER_SIZE];
+	int ret;
+	int handle;
+
+	fd = open_mmfs_device();
+
+	memset(&mmap, 0, sizeof(mmap));
+	mmap.handle = 0x10101010;
+	mmap.offset = 0;
+	mmap.size = 4096;
+	printf("Testing mmaping of bad object.\n");
+	ret = ioctl(fd, MMFS_IOCTL_MMAP, &mmap);
+	assert(ret == -1 && errno == EINVAL);
+
+	memset(&alloc, 0, sizeof(alloc));
+	alloc.size = MMFS_BUFFER_SIZE;
+	ret = ioctl(fd, MMFS_IOCTL_ALLOC, &alloc);
+	assert(ret == 0);
+	handle = alloc.handle;
+
+	printf("Testing mmaping of newly allocated object.\n");
+	mmap.handle = handle;
+	mmap.offset = 0;
+	mmap.size = MMFS_BUFFER_SIZE;
+	ret = ioctl(fd, MMFS_IOCTL_MMAP, &mmap);
+	assert(ret == 0);
+
+	printf("Testing contents of newly allocated object.\n");
+	memset(expected, 0, sizeof(expected));
+	assert(memcmp(mmap.addr, expected, sizeof(expected)) == 0);
+
+	printf("Testing coherency of writes and mmap reads.\n");
+	memset(buf, 0, sizeof(buf));
+	memset(buf + 1024, 0x01, 1024);
+	memset(expected + 1024, 0x01, 1024);
+	ret = do_write(fd, handle, buf, 0, MMFS_BUFFER_SIZE);
+	assert(ret == 0);
+	assert(memcmp(buf, mmap.addr, sizeof(buf)) == 0);
+
+	printf("Testing that mapping stays after unreference\n");
+	unref.handle = handle;
+	ret = ioctl(fd, MMFS_IOCTL_UNREFERENCE, &unref);
+	assert(ret == 0);
+	assert(memcmp(buf, mmap.addr, sizeof(buf)) == 0);
+
+	printf("Testing unmapping\n");
+	munmap(mmap.addr, MMFS_BUFFER_SIZE);
+
+	close(fd);
+
+	return 0;
+}