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authorCarl Henrik Lunde <chlunde@ping.uio.no>2008-06-12 20:13:58 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2008-06-12 11:20:57 -0700
commit14a73f54798f39854e521fb596da7d50b7566bbd (patch)
tree2c9055792b004d21a9ca52660b036ca92de057ea /block
parent95dcf8350dc889e735d03c0debe2f7b26d243185 (diff)
downloadlinux-2.6.34-ux500-14a73f54798f39854e521fb596da7d50b7566bbd.tar.gz
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>
Diffstat (limited to 'block')
-rw-r--r--block/blktrace.c10
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);