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powerpc: Honor O_NONBLOCK flag when reading RTAS log

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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>
This commit is contained in:
Vitaly Mayatskikh 2008-09-28 23:24:33 +00:00 committed by Benjamin Herrenschmidt
parent 3396c72b92
commit 76c31f239e
1 changed files with 18 additions and 8 deletions
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26
arch/powerpc/platforms/pseries/rtasd.c
View file

@ -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)
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();
spin_unlock_irqrestore(&rtasd_log_lock, s);
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);
}
error = wait_event_interruptible(rtas_log_wait, rtas_log_size);
if (error)
goto out;
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);