include/linux/blktrace_api.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef BLKTRACE_H
0003 #define BLKTRACE_H
0004
0005 #include <linux/blk-mq.h>
0006 #include <linux/relay.h>
0007 #include <linux/compat.h>
0008 #include <uapi/linux/blktrace_api.h>
0009 #include <linux/list.h>
0010 #include <linux/blk_types.h>
0011
0012 #if defined(CONFIG_BLK_DEV_IO_TRACE)
0013
0014 #include <linux/sysfs.h>
0015
0016 struct blk_trace {
0017     int trace_state;
0018     struct rchan *rchan;
0019     unsigned long __percpu *sequence;
0020     unsigned char __percpu *msg_data;
0021     u16 act_mask;
0022     u64 start_lba;
0023     u64 end_lba;
0024     u32 pid;
0025     u32 dev;
0026     struct dentry *dir;
0027     struct list_head running_list;
0028     atomic_t dropped;
0029 };
0030
0031 extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
0032 extern void blk_trace_shutdown(struct request_queue *);
0033 __printf(3, 4) void __blk_trace_note_message(struct blk_trace *bt,
0034         struct cgroup_subsys_state *css, const char *fmt, ...);
0035
0036 /**
0037  * blk_add_trace_msg - Add a (simple) message to the blktrace stream
0038  * @q:      queue the io is for
0039  * @fmt:    format to print message in
0040  * args...  Variable argument list for format
0041  *
0042  * Description:
0043  *     Records a (simple) message onto the blktrace stream.
0044  *
0045  *     NOTE: BLK_TN_MAX_MSG characters are output at most.
0046  *     NOTE: Can not use 'static inline' due to presence of var args...
0047  *
0048  **/
0049 #define blk_add_cgroup_trace_msg(q, css, fmt, ...)          \
0050     do {                                \
0051         struct blk_trace *bt;                   \
0052                                     \
0053         rcu_read_lock();                    \
0054         bt = rcu_dereference((q)->blk_trace);           \
0055         if (unlikely(bt))                   \
0056             __blk_trace_note_message(bt, css, fmt, ##__VA_ARGS__);\
0057         rcu_read_unlock();                  \
0058     } while (0)
0059 #define blk_add_trace_msg(q, fmt, ...)                  \
0060     blk_add_cgroup_trace_msg(q, NULL, fmt, ##__VA_ARGS__)
0061 #define BLK_TN_MAX_MSG      128
0062
0063 static inline bool blk_trace_note_message_enabled(struct request_queue *q)
0064 {
0065     struct blk_trace *bt;
0066     bool ret;
0067
0068     rcu_read_lock();
0069     bt = rcu_dereference(q->blk_trace);
0070     ret = bt && (bt->act_mask & BLK_TC_NOTIFY);
0071     rcu_read_unlock();
0072     return ret;
0073 }
0074
0075 extern void blk_add_driver_data(struct request *rq, void *data, size_t len);
0076 extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
0077                struct block_device *bdev,
0078                char __user *arg);
0079 extern int blk_trace_startstop(struct request_queue *q, int start);
0080 extern int blk_trace_remove(struct request_queue *q);
0081
0082 #else /* !CONFIG_BLK_DEV_IO_TRACE */
0083 # define blk_trace_ioctl(bdev, cmd, arg)        (-ENOTTY)
0084 # define blk_trace_shutdown(q)              do { } while (0)
0085 # define blk_add_driver_data(rq, data, len)     do {} while (0)
0086 # define blk_trace_setup(q, name, dev, bdev, arg)   (-ENOTTY)
0087 # define blk_trace_startstop(q, start)          (-ENOTTY)
0088 # define blk_trace_remove(q)                (-ENOTTY)
0089 # define blk_add_trace_msg(q, fmt, ...)         do { } while (0)
0090 # define blk_add_cgroup_trace_msg(q, cg, fmt, ...)  do { } while (0)
0091 # define blk_trace_note_message_enabled(q)      (false)
0092 #endif /* CONFIG_BLK_DEV_IO_TRACE */
0093
0094 #ifdef CONFIG_COMPAT
0095
0096 struct compat_blk_user_trace_setup {
0097     char name[BLKTRACE_BDEV_SIZE];
0098     u16 act_mask;
0099     u32 buf_size;
0100     u32 buf_nr;
0101     compat_u64 start_lba;
0102     compat_u64 end_lba;
0103     u32 pid;
0104 };
0105 #define BLKTRACESETUP32 _IOWR(0x12, 115, struct compat_blk_user_trace_setup)
0106
0107 #endif
0108
0109 void blk_fill_rwbs(char *rwbs, blk_opf_t opf);
0110
0111 static inline sector_t blk_rq_trace_sector(struct request *rq)
0112 {
0113     /*
0114      * Tracing should ignore starting sector for passthrough requests and
0115      * requests where starting sector didn't get set.
0116      */
0117     if (blk_rq_is_passthrough(rq) || blk_rq_pos(rq) == (sector_t)-1)
0118         return 0;
0119     return blk_rq_pos(rq);
0120 }
0121
0122 static inline unsigned int blk_rq_trace_nr_sectors(struct request *rq)
0123 {
0124     return blk_rq_is_passthrough(rq) ? 0 : blk_rq_sectors(rq);
0125 }
0126
0127 #endif