Initial commit of blktap kernel files

jonludlam · Nov 4, 2011 · f6a983c · f6a983c
commit f6a983c
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diff --git a/Makefile b/Makefile
@@ -0,0 +1,3 @@
+obj-m := blktap.o
+
+blktap-objs := control.o ring.o device.o request.o sysfs.o
diff --git a/README b/README
@@ -0,0 +1,8 @@
+The kernel module for blktap2
+
+To compile:
+
+make -C /lib/modules/`uname -r`/build M=$PWD
+
+Tested on debian sid, with linux-image-3.0.0-rc3-686-pae
+
diff --git a/blktap.h b/blktap.h
@@ -0,0 +1,162 @@
+#ifndef _BLKTAP_H_
+#define _BLKTAP_H_
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/init.h>
+#include <linux/scatterlist.h>
+#include "linux-blktap.h"
+
+extern int blktap_debug_level;
+extern int blktap_ring_major;
+extern int blktap_device_major;
+
+#define BTPRINTK(level, tag, force, _f, _a...)				\
+	do {								\
+		if (blktap_debug_level > level &&			\
+		    (force || printk_ratelimit()))			\
+			printk(tag "%s: " _f, __func__, ##_a);		\
+	} while (0)
+
+#define BTDBG(_f, _a...)             BTPRINTK(8, KERN_DEBUG, 1, _f, ##_a)
+#define BTINFO(_f, _a...)            BTPRINTK(0, KERN_INFO, 0, _f, ##_a)
+#define BTWARN(_f, _a...)            BTPRINTK(0, KERN_WARNING, 0, _f, ##_a)
+#define BTERR(_f, _a...)             BTPRINTK(0, KERN_ERR, 0, _f, ##_a)
+
+#define MAX_BLKTAP_DEVICE            1024
+
+#define BLKTAP_DEVICE                4
+#define BLKTAP_DEVICE_CLOSED         5
+#define BLKTAP_SHUTDOWN_REQUESTED    8
+
+#define BLKTAP_REQUEST_FREE          0
+#define BLKTAP_REQUEST_PENDING       1
+
+struct blktap_device {
+	spinlock_t                     lock;
+	struct gendisk                *gd;
+};
+
+struct blktap_request;
+
+struct blktap_ring {
+	struct task_struct            *task;
+
+	struct vm_area_struct         *vma;
+	struct blktap_front_ring       ring;
+	unsigned long                  ring_vstart;
+	unsigned long                  user_vstart;
+
+	int                            n_pending;
+	struct blktap_request         *pending[BLKTAP_RING_SIZE];
+
+	wait_queue_head_t              poll_wait;
+
+	dev_t                          devno;
+	struct device                 *dev;
+};
+
+struct blktap_statistics {
+	unsigned long                  st_print;
+	int                            st_rd_req;
+	int                            st_wr_req;
+	int                            st_tr_req;
+	int                            st_oo_req;
+	int                            st_fl_req;
+	int                            st_rd_sect;
+	int                            st_wr_sect;
+	int                            st_tr_sect;
+	s64                            st_rd_cnt;
+	s64                            st_rd_sum_usecs;
+	s64                            st_rd_max_usecs;
+	s64                            st_wr_cnt;
+	s64                            st_wr_sum_usecs;
+	s64                            st_wr_max_usecs;	
+};
+
+struct blktap_request {
+	struct blktap                 *tap;
+	struct request                *rq;
+	int                            usr_idx;
+
+	int                            operation;
+
+	struct scatterlist             sg_table[BLKTAP_SEGMENT_MAX];
+	struct page                   *pages[BLKTAP_SEGMENT_MAX];
+	int                            nr_pages;
+};
+
+#define blktap_for_each_sg(_sg, _req, _i)	\
+	for (_sg = (_req)->sg_table, _i = 0;	\
+	     _i < (_req)->nr_pages;		\
+	     (_sg)++, (_i)++)
+
+struct blktap {
+	int                            minor;
+	unsigned long                  dev_inuse;
+
+	struct blktap_ring             ring;
+	struct blktap_device           device;
+	struct blktap_page_pool       *pool;
+
+	wait_queue_head_t              remove_wait;
+	struct work_struct             remove_work;
+	char                           name[BLKTAP_NAME_MAX];
+
+	struct blktap_statistics       stats;
+};
+
+struct blktap_page_pool {
+	struct mempool_s              *bufs;
+	spinlock_t                     lock;
+	struct kobject                 kobj;
+	wait_queue_head_t              wait;
+};
+
+extern struct mutex blktap_lock;
+extern struct blktap **blktaps;
+extern int blktap_max_minor;
+
+int blktap_control_destroy_tap(struct blktap *);
+size_t blktap_control_debug(struct blktap *, char *, size_t);
+
+int blktap_ring_init(void);
+void blktap_ring_exit(void);
+size_t blktap_ring_debug(struct blktap *, char *, size_t);
+int blktap_ring_create(struct blktap *);
+int blktap_ring_destroy(struct blktap *);
+struct blktap_request *blktap_ring_make_request(struct blktap *);
+void blktap_ring_free_request(struct blktap *,struct blktap_request *);
+void blktap_ring_submit_request(struct blktap *, struct blktap_request *);
+int blktap_ring_map_request(struct blktap *, struct file *, struct blktap_request *);
+void blktap_ring_unmap_request(struct blktap *, struct blktap_request *);
+void blktap_ring_set_message(struct blktap *, int);
+void blktap_ring_kick_user(struct blktap *);
+
+int blktap_sysfs_init(void);
+void blktap_sysfs_exit(void);
+int blktap_sysfs_create(struct blktap *);
+void blktap_sysfs_destroy(struct blktap *);
+
+int blktap_device_init(void);
+void blktap_device_exit(void);
+size_t blktap_device_debug(struct blktap *, char *, size_t);
+int blktap_device_create(struct blktap *, struct blktap_device_info *);
+int blktap_device_destroy(struct blktap *);
+void blktap_device_destroy_sync(struct blktap *);
+void blktap_device_run_queue(struct blktap *, struct file *);
+void blktap_device_end_request(struct blktap *, struct blktap_request *, int);
+
+int blktap_page_pool_init(struct kobject *);
+void blktap_page_pool_exit(void);
+struct blktap_page_pool *blktap_page_pool_get(const char *);
+
+size_t blktap_request_debug(struct blktap *, char *, size_t);
+struct blktap_request *blktap_request_alloc(struct blktap *);
+int blktap_request_get_pages(struct blktap *, struct blktap_request *, int);
+void blktap_request_free(struct blktap *, struct blktap_request *);
+void blktap_request_bounce(struct blktap *, struct blktap_request *, int);
+
+
+#endif