1 // SPDX-License-Identifier: GPL-2.0-only
3  * Read/write thread of a guest agent for virtio-trace
16 #include "trace-agent.h"
30 	rw_ti->cpu_num = -1;  in rw_thread_info_new()
31 	rw_ti->in_fd = -1;  in rw_thread_info_new()
32 	rw_ti->out_fd = -1;  in rw_thread_info_new()
33 	rw_ti->read_pipe = -1;  in rw_thread_info_new()
34 	rw_ti->write_pipe = -1;  in rw_thread_info_new()
35 	rw_ti->pipe_size = PIPE_INIT;  in rw_thread_info_new()
40 void *rw_thread_init(int cpu, const char *in_path, const char *out_path,  in rw_thread_init()  argument
46 	rw_ti->cpu_num = cpu;  in rw_thread_init()
48 	/* set read(input) fd */  in rw_thread_init()
49 	rw_ti->in_fd = open(in_path, O_RDONLY);  in rw_thread_init()
50 	if (rw_ti->in_fd == -1) {  in rw_thread_init()
51 		pr_err("Could not open in_fd (CPU:%d)\n", cpu);  in rw_thread_init()
57 		/* virtio-serial output mode */  in rw_thread_init()
58 		rw_ti->out_fd = open(out_path, O_WRONLY);  in rw_thread_init()
59 		if (rw_ti->out_fd == -1) {  in rw_thread_init()
60 			pr_err("Could not open out_fd (CPU:%d)\n", cpu);  in rw_thread_init()
65 		rw_ti->out_fd = STDOUT_FILENO;  in rw_thread_init()
68 		pr_err("Could not create pipe in rw-thread(%d)\n", cpu);  in rw_thread_init()
74 	 * To read/write trace data speedy, pipe size is changed.  in rw_thread_init()
77 		pr_err("Could not change pipe size in rw-thread(%d)\n", cpu);  in rw_thread_init()
81 	rw_ti->read_pipe = data_pipe[1];  in rw_thread_init()
82 	rw_ti->write_pipe = data_pipe[0];  in rw_thread_init()
83 	rw_ti->pipe_size = pipe_size;  in rw_thread_init()
91 /* Bind a thread to a cpu */
100 	if (sched_setaffinity(0, sizeof(mask), &mask) == -1)  in bind_cpu()
101 		pr_err("Could not set CPU#%d affinity\n", (int)cpu_num);  in bind_cpu()
110 	bind_cpu(ts->cpu_num);  in rw_thread_main()
113 		/* Wait for a read order of trace data by Host OS */  in rw_thread_main()
124 		 * Each thread read trace_pipe_raw of each cpu bounding the  in rw_thread_main()
125 		 * thread, so contention of multi-threads does not occur.  in rw_thread_main()
127 		rlen = splice(ts->in_fd, NULL, ts->read_pipe, NULL,  in rw_thread_main()
128 				ts->pipe_size, SPLICE_F_MOVE | SPLICE_F_MORE);  in rw_thread_main()
131 			pr_err("Splice_read in rw-thread(%d)\n", ts->cpu_num);  in rw_thread_main()
138 			 * ring-buffer.  in rw_thread_main()
141 			pr_debug("Read retry(cpu:%d)\n", ts->cpu_num);  in rw_thread_main()
148 			ret = splice(ts->write_pipe, NULL, ts->out_fd, NULL,  in rw_thread_main()
149 					rlen - wlen,  in rw_thread_main()
153 				pr_err("Splice_write in rw-thread(%d)\n",  in rw_thread_main()
154 								ts->cpu_num);  in rw_thread_main()
161 				 * non-blocking mode. Then, writer might be  in rw_thread_main()
164 				 * non-blocking mode.  in rw_thread_main()
185 		pr_err("Could not create a rw thread(%d)\n", rw_ti->cpu_num);  in rw_thread_run()