sched/rt, fs: Use CONFIG_PREEMPTION

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the i_size() and part_nr_sects_…() code over to use
CONFIG_PREEMPTION. Update the comment for fsstack_copy_inode_size() also
to refer to CONFIG_PREEMPTION.

[bigeasy: +PREEMPT comments]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20191015191821.11479-24-bigeasy@linutronix.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

fs/stack.c

@@ -23,7 +23,7 @@ void fsstack_copy_inode_size(struct inode *dst, struct inode *src)
 
 	/*
 	 * But on 32-bit, we ought to make an effort to keep the two halves of
-	 * i_blocks in sync despite SMP or PREEMPT - though stat's
+	 * i_blocks in sync despite SMP or PREEMPTION - though stat's
 	 * generic_fillattr() doesn't bother, and we won't be applying quotas
 	 * (where i_blocks does become important) at the upper level.
 	 *
@@ -38,14 +38,14 @@ void fsstack_copy_inode_size(struct inode *dst, struct inode *src)
 		spin_unlock(&src->i_lock);
 
 	/*
-	 * If CONFIG_SMP or CONFIG_PREEMPT on 32-bit, it's vital for
+	 * If CONFIG_SMP or CONFIG_PREEMPTION on 32-bit, it's vital for
 	 * fsstack_copy_inode_size() to hold some lock around
 	 * i_size_write(), otherwise i_size_read() may spin forever (see
 	 * include/linux/fs.h).  We don't necessarily hold i_mutex when this
 	 * is called, so take i_lock for that case.
 	 *
 	 * And if on 32-bit, continue our effort to keep the two halves of
-	 * i_blocks in sync despite SMP or PREEMPT: use i_lock  for that case
+	 * i_blocks in sync despite SMP or PREEMPTION: use i_lock for that case
 	 * too, and do both at once by combining the tests.
 	 *
 	 * There is none of this locking overhead in the 64-bit case.

include/linux/fs.h

@@ -855,7 +855,7 @@ static inline loff_t i_size_read(const struct inode *inode)
 		i_size = inode->i_size;
 	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
 	return i_size;
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	loff_t i_size;
 
 	preempt_disable();
@@ -880,7 +880,7 @@ static inline void i_size_write(struct inode *inode, loff_t i_size)
 	inode->i_size = i_size;
 	write_seqcount_end(&inode->i_size_seqcount);
 	preempt_enable();
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	preempt_disable();
 	inode->i_size = i_size;
 	preempt_enable();

include/linux/genhd.h

@@ -718,7 +718,7 @@ static inline void hd_free_part(struct hd_struct *part)
  * accessor function.
  *
  * Code written along the lines of i_size_read() and i_size_write().
- * CONFIG_PREEMPT case optimizes the case of UP kernel with preemption
+ * CONFIG_PREEMPTION case optimizes the case of UP kernel with preemption
  * on.
  */
 static inline sector_t part_nr_sects_read(struct hd_struct *part)
@@ -731,7 +731,7 @@ static inline sector_t part_nr_sects_read(struct hd_struct *part)
 		nr_sects = part->nr_sects;
 	} while (read_seqcount_retry(&part->nr_sects_seq, seq));
 	return nr_sects;
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	sector_t nr_sects;
 
 	preempt_disable();
@@ -754,7 +754,7 @@ static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
 	write_seqcount_begin(&part->nr_sects_seq);
 	part->nr_sects = size;
 	write_seqcount_end(&part->nr_sects_seq);
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	preempt_disable();
 	part->nr_sects = size;
 	preempt_enable();