From: Pekka Paalanen Date: Mon, 12 May 2008 19:21:02 +0000 (+0200) Subject: ftrace: add readpos to struct trace_seq; add trace_seq_to_user() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6c6c27969a4c6024e6c8838829546c02aaddca18;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git ftrace: add readpos to struct trace_seq; add trace_seq_to_user() Refactor code from tracing_read_pipe() and create trace_seq_to_user(). Moved trace_seq_reset() call before iter->trace->read() call so that when all leftover data is returned, trace_seq is reset automatically. Signed-off-by: Pekka Paalanen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c232d8248a09..82ced406aacf 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -400,6 +400,26 @@ static void trace_seq_reset(struct trace_seq *s) { s->len = 0; + s->readpos = 0; +} + +ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) +{ + int len; + int ret; + + if (s->len <= s->readpos) + return -EBUSY; + + len = s->len - s->readpos; + if (cnt > len) + cnt = len; + ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); + if (ret) + return -EFAULT; + + s->readpos += len; + return cnt; } static void @@ -2361,46 +2381,32 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, struct trace_iterator *iter = filp->private_data; struct trace_array_cpu *data; static cpumask_t mask; - static int start; unsigned long flags; #ifdef CONFIG_FTRACE int ftrace_save; #endif - int read = 0; int cpu; - int len; - int ret; + ssize_t sret; /* return any leftover data */ - if (iter->seq.len > start) { - len = iter->seq.len - start; - if (cnt > len) - cnt = len; - ret = copy_to_user(ubuf, iter->seq.buffer + start, cnt); - if (ret) - cnt = -EFAULT; - - start += len; + sret = trace_seq_to_user(&iter->seq, ubuf, cnt); + if (sret != -EBUSY) + return sret; + sret = 0; - return cnt; - } + trace_seq_reset(&iter->seq); mutex_lock(&trace_types_lock); if (iter->trace->read) { - ret = iter->trace->read(iter, filp, ubuf, cnt, ppos); - if (ret) { - read = ret; + sret = iter->trace->read(iter, filp, ubuf, cnt, ppos); + if (sret) goto out; - } } - trace_seq_reset(&iter->seq); - start = 0; - while (trace_empty(iter)) { if ((filp->f_flags & O_NONBLOCK)) { - read = -EAGAIN; + sret = -EAGAIN; goto out; } @@ -2426,7 +2432,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, iter->tr->waiter = NULL; if (signal_pending(current)) { - read = -EINTR; + sret = -EINTR; goto out; } @@ -2496,6 +2502,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, } while (find_next_entry_inc(iter) != NULL) { + int ret; int len = iter->seq.len; ret = print_trace_line(iter); @@ -2526,24 +2533,16 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, local_irq_restore(flags); /* Now copy what we have to the user */ - read = iter->seq.len; - if (read > cnt) - read = cnt; - - ret = copy_to_user(ubuf, iter->seq.buffer, read); - - if (read < iter->seq.len) - start = read; - else + sret = trace_seq_to_user(&iter->seq, ubuf, cnt); + if (iter->seq.readpos >= iter->seq.len) trace_seq_reset(&iter->seq); - - if (ret) - read = -EFAULT; + if (sret == -EBUSY) + sret = 0; out: mutex_unlock(&trace_types_lock); - return read; + return sret; } static ssize_t diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ee53d706066f..8845033ab49d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -155,6 +155,7 @@ struct tracer { struct trace_seq { unsigned char buffer[PAGE_SIZE]; unsigned int len; + unsigned int readpos; }; /* @@ -301,6 +302,8 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace, extern void *head_page(struct trace_array_cpu *data); extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...); +extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, + size_t cnt); extern long ns2usecs(cycle_t nsec); extern unsigned long trace_flags;