Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
blktrace: split out relaying a blktrace event
Split out the code relaying a blktrace event to user-space using relayfs.
This enables adding a second version supporting a new version of the
protocol.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
authored by
Johannes Thumshirn
and committed by
Jens Axboe
04678e72
472eca53
+32
-28
+32
-28
kernel/trace/blktrace.c
+32
-28
kernel/trace/blktrace.c
···
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memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
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}
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+
static void relay_blktrace_event(struct blk_trace *bt, unsigned long sequence,
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pid_t pid, int cpu, sector_t sector, int bytes,
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u32 what, int error, u64 cgid,
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ssize_t cgid_len, void *pdu_data, int pdu_len)
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{
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struct blk_io_trace *t;
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size_t trace_len = sizeof(*t) + pdu_len + cgid_len;
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+
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t = relay_reserve(bt->rchan, trace_len);
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if (!t)
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return;
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+
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t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
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t->sequence = sequence;
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t->time = ktime_to_ns(ktime_get());
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+
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record_blktrace_event(t, pid, cpu, sector, bytes, what, bt->dev, error,
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cgid, cgid_len, pdu_data, pdu_len);
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}
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+
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/*
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* Send out a notify message.
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*/
···
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if (!bt->rchan)
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return;
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-
t = relay_reserve(bt->rchan, trace_len);
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-
if (t) {
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t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
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t->time = ktime_to_ns(ktime_get());
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-
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record_blktrace_event(t, pid, cpu, 0, 0,
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action | (cgid ? __BLK_TN_CGROUP : 0),
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bt->dev, 0, cgid, cgid_len, (void *)data,
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len);
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-
}
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relay_blktrace_event(bt, 0, pid, cpu, 0, 0,
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action | (cgid ? __BLK_TN_CGROUP : 0), 0, cgid,
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cgid_len, (void *)data, len);
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}
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/*
···
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struct task_struct *tsk = current;
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struct ring_buffer_event *event = NULL;
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struct trace_buffer *buffer = NULL;
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-
struct blk_io_trace *t;
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unsigned long flags = 0;
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unsigned long *sequence;
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unsigned int trace_ctx = 0;
···
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return;
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cpu = raw_smp_processor_id();
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-
trace_len = sizeof(*t) + pdu_len + cgid_len;
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if (blk_tracer) {
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tracing_record_cmdline(current);
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buffer = blk_tr->array_buffer.buffer;
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trace_ctx = tracing_gen_ctx_flags(0);
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trace_len = sizeof(struct blk_io_trace) + pdu_len + cgid_len;
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event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
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trace_len, trace_ctx);
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if (!event)
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return;
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-
t = ring_buffer_event_data(event);
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-
record_blktrace_event(t, pid, cpu, sector, bytes, what, bt->dev,
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-
error, cgid, cgid_len, pdu_data, pdu_len);
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record_blktrace_event(ring_buffer_event_data(event),
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pid, cpu, sector, bytes, what, bt->dev,
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error, cgid, cgid_len, pdu_data,
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pdu_len);
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trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
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return;
···
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* from coming in and stepping on our toes.
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*/
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local_irq_save(flags);
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-
t = relay_reserve(bt->rchan, trace_len);
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-
if (t) {
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-
sequence = per_cpu_ptr(bt->sequence, cpu);
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-
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t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
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t->sequence = ++(*sequence);
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t->time = ktime_to_ns(ktime_get());
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-
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record_blktrace_event(t, pid, cpu, sector, bytes, what,
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bt->dev, error, cgid, cgid_len,
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pdu_data, pdu_len);
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-
}
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-
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sequence = per_cpu_ptr(bt->sequence, cpu);
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(*sequence)++;
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relay_blktrace_event(bt, *sequence, pid, cpu, sector, bytes, what,
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error, cgid, cgid_len, pdu_data, pdu_len);
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local_irq_restore(flags);
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}
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