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authorThomas Gleixner <tglx@linutronix.de>2012-03-01 16:12:47 +0100
committerSteven Rostedt <rostedt@goodmis.org>2012-05-14 12:37:24 -0400
commitadc36a76b4bc82fa59740582446d71a9d6375c68 (patch)
treeaeba7c1cc910402784afb91d380d1e838a77e7eb
parent3578b387e062f6bb626c3dcad4f632039fe1fa33 (diff)
fs: Protect open coded isize seqcount
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>
-rw-r--r--include/linux/fs.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9c852175e460..c7984a57232d 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;