From: Chao Yu <chao2.yu@samsung.com>
Date: Wed, 11 Feb 2015 10:20:38 +0000 (+0800)
Subject: f2fs: use spinlock for segmap_lock instead of rwlock
X-Git-Tag: omap-for-v4.1/prcm-dts-mfd-syscon-fix~98^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1a118ccfd60fc78e64c0a3ab9e85075545839d6e;p=pandora-kernel.git

f2fs: use spinlock for segmap_lock instead of rwlock

rwlock can provide better concurrency when there are much more readers than
writers because readers can hold the rwlock simultaneously.

But now, for segmap_lock rwlock in struct free_segmap_info, there is only one
reader 'mount' from below call path:
->f2fs_fill_super
  ->build_segment_manager
    ->build_dirty_segmap
      ->init_dirty_segmap
        ->find_next_inuse
          read_lock
          ...
          read_unlock

Now that our concurrency can not be improved since there is no other reader for
this lock, we do not need to use rwlock_t type for segmap_lock, let's replace it
with spinlock_t type.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

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