From 76c31f239ea221a6c84bd26141262a43bfe8b7f4 Mon Sep 17 00:00:00 2001
From: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Date: Sun, 28 Sep 2008 23:24:33 +0000
Subject: powerpc: Honor O_NONBLOCK flag when reading RTAS log
rtas_log_read() doesn't check file flags for O_NONBLOCK and blocks
non-blocking readers of /proc/ppc64/rtas/error_log when there is
no data available. This fixes it.
Also rtas_log_read() returns now with ENODATA to prevent suspending of
process in wait_event_interruptible() when logging facility was
switched off and log is already empty.
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/platforms/pseries/rtasd.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
(limited to 'arch/powerpc/platforms')
diff --git a/arch/powerpc/platforms/pseries/rtasd.c b/arch/powerpc/platforms/pseries/rtasd.c
index c9ffd8c..f4e55be 100644
--- a/arch/powerpc/platforms/pseries/rtasd.c
+++ b/arch/powerpc/platforms/pseries/rtasd.c
@@ -295,19 +295,29 @@ static ssize_t rtas_log_read(struct file * file, char __user * buf,
if (!tmp)
return -ENOMEM;
-
spin_lock_irqsave(&rtasd_log_lock, s);
/* if it's 0, then we know we got the last one (the one in NVRAM) */
- if (rtas_log_size == 0 && logging_enabled)
- nvram_clear_error_log();
- spin_unlock_irqrestore(&rtasd_log_lock, s);
+ while (rtas_log_size == 0) {
+ if (file->f_flags & O_NONBLOCK) {
+ spin_unlock_irqrestore(&rtasd_log_lock, s);
+ error = -EAGAIN;
+ goto out;
+ }
+ if (!logging_enabled) {
+ spin_unlock_irqrestore(&rtasd_log_lock, s);
+ error = -ENODATA;
+ goto out;
+ }
+ nvram_clear_error_log();
- error = wait_event_interruptible(rtas_log_wait, rtas_log_size);
- if (error)
- goto out;
+ spin_unlock_irqrestore(&rtasd_log_lock, s);
+ error = wait_event_interruptible(rtas_log_wait, rtas_log_size);
+ if (error)
+ goto out;
+ spin_lock_irqsave(&rtasd_log_lock, s);
+ }
- spin_lock_irqsave(&rtasd_log_lock, s);
offset = rtas_error_log_buffer_max * (rtas_log_start & LOG_NUMBER_MASK);
memcpy(tmp, &rtas_log_buf[offset], count);
--
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