diff options
| author | Carl Henrik Lunde <chlunde@ping.uio.no> | 2008-06-12 20:13:58 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-06-12 11:20:57 -0700 |
| commit | 14a73f54798f39854e521fb596da7d50b7566bbd (patch) | |
| tree | 2c9055792b004d21a9ca52660b036ca92de057ea | |
| parent | 95dcf8350dc889e735d03c0debe2f7b26d243185 (diff) | |
block: disable IRQs until data is written to relay channel
As we may run relay_reserve from interrupt context we must always disable
IRQs. This is because a call to relay_reserve may expose previously written
data to use space.
Updated new message code and an old but related comment.
Signed-off-by: Carl Henrik Lunde <chlunde@ping.uio.no>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | block/blktrace.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/block/blktrace.c b/block/blktrace.c index 7ae87cc4a16..8d3a2778026 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -79,16 +79,17 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) { int n; va_list args; + unsigned long flags; char *buf; - preempt_disable(); + local_irq_save(flags); buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); va_start(args, fmt); n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); va_end(args); trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); - preempt_enable(); + local_irq_restore(flags); } EXPORT_SYMBOL_GPL(__trace_note_message); @@ -158,10 +159,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, /* * A word about the locking here - we disable interrupts to reserve * some space in the relay per-cpu buffer, to prevent an irq - * from coming in and stepping on our toes. Once reserved, it's - * enough to get preemption disabled to prevent read of this data - * before we are through filling it. get_cpu()/put_cpu() does this - * for us + * from coming in and stepping on our toes. */ local_irq_save(flags); |