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    Subject[PATCH RT 17/25][RFC 3.0.23-rt39-rc1] fs: Protect open coded isize seqcount
    From: Thomas Gleixner <tglx@linutronix.de>

    A writer might be preempted in the write side critical section on
    RT. Disable preemption to avoid endless spinning of a preempting
    reader.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: stable-rt@vger.kernel.org
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
    ---
    include/linux/fs.h | 2 ++
    1 files changed, 2 insertions(+), 0 deletions(-)

    diff --git a/include/linux/fs.h b/include/linux/fs.h
    index 9c85217..c7984a5 100644
    --- a/include/linux/fs.h
    +++ b/include/linux/fs.h
    @@ -876,9 +876,11 @@ static inline loff_t i_size_read(const struct inode *inode)
    static inline void i_size_write(struct inode *inode, loff_t i_size)
    {
    #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
    + preempt_disable_rt();
    write_seqcount_begin(&inode->i_size_seqcount);
    inode->i_size = i_size;
    write_seqcount_end(&inode->i_size_seqcount);
    + preempt_enable_rt();
    #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
    preempt_disable();
    inode->i_size = i_size;
    --
    1.7.8.3



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