[jffs2] kill wbuf_queued/wbuf_dwork_lock

schedule_delayed_work() happening when the work is already pending is
a cheap no-op.  Don't bother with ->wbuf_queued logics - it's both
broken (cancelling ->wbuf_dwork leaves it set, as spotted by Jeff Harris)
and pointless.  It's cheaper to let schedule_delayed_work() handle that
case.

Reported-by: Jeff Harris <jefftharris@gmail.com>
Tested-by: Jeff Harris <jefftharris@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 2 insertions, 17 deletions

diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index 413ef89c2d1b..046fee8b6e9b 100644
--- a/fs/jffs2/jffs2_fs_sb.h
+++ b/fs/jffs2/jffs2_fs_sb.h
@@ -134,8 +134,6 @@ struct jffs2_sb_info {
         struct rw_semaphore wbuf_sem;   /* Protects the write buffer */
 
         struct delayed_work wbuf_dwork; /* write-buffer write-out work */
-        int wbuf_queued;                /* non-zero delayed work is queued */
-        spinlock_t wbuf_dwork_lock;     /* protects wbuf_dwork and and wbuf_queued */
 
         unsigned char *oobbuf;
         int oobavail; /* How many bytes are available for JFFS2 in OOB */
diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
index a6597d60d76d..09ed55190ee2 100644
--- a/fs/jffs2/wbuf.c
+++ b/fs/jffs2/wbuf.c
@@ -1162,10 +1162,6 @@ static void delayed_wbuf_sync(struct work_struct *work)
         struct jffs2_sb_info *c = work_to_sb(work);
         struct super_block *sb = OFNI_BS_2SFFJ(c);
 
-        spin_lock(&c->wbuf_dwork_lock);
-        c->wbuf_queued = 0;
-        spin_unlock(&c->wbuf_dwork_lock);
-
         if (!(sb->s_flags & MS_RDONLY)) {
                 jffs2_dbg(1, "%s()\n", __func__);
                 jffs2_flush_wbuf_gc(c, 0);
@@ -1180,14 +1176,9 @@ void jffs2_dirty_trigger(struct jffs2_sb_info *c)
         if (sb->s_flags & MS_RDONLY)
                 return;
 
-        spin_lock(&c->wbuf_dwork_lock);
-        if (!c->wbuf_queued) {
+        delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+        if (queue_delayed_work(system_long_wq, &c->wbuf_dwork, delay))
                 jffs2_dbg(1, "%s()\n", __func__);
-                delay = msecs_to_jiffies(dirty_writeback_interval * 10);
-                queue_delayed_work(system_long_wq, &c->wbuf_dwork, delay);
-                c->wbuf_queued = 1;
-        }
-        spin_unlock(&c->wbuf_dwork_lock);
 }
 
 int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
@@ -1211,7 +1202,6 @@ int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
 
         /* Initialise write buffer */
         init_rwsem(&c->wbuf_sem);
-        spin_lock_init(&c->wbuf_dwork_lock);
         INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
         c->wbuf_pagesize = c->mtd->writesize;
         c->wbuf_ofs = 0xFFFFFFFF;
@@ -1251,7 +1241,6 @@ int jffs2_dataflash_setup(struct jffs2_sb_info *c) {
 
         /* Initialize write buffer */
         init_rwsem(&c->wbuf_sem);
-        spin_lock_init(&c->wbuf_dwork_lock);
         INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
         c->wbuf_pagesize =  c->mtd->erasesize;
 
@@ -1311,7 +1300,6 @@ int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c) {
 
         /* Initialize write buffer */
         init_rwsem(&c->wbuf_sem);
-        spin_lock_init(&c->wbuf_dwork_lock);
         INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
 
         c->wbuf_pagesize = c->mtd->writesize;
@@ -1346,7 +1334,6 @@ int jffs2_ubivol_setup(struct jffs2_sb_info *c) {
                 return 0;
 
         init_rwsem(&c->wbuf_sem);
-        spin_lock_init(&c->wbuf_dwork_lock);
         INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
 
         c->wbuf_pagesize =  c->mtd->writesize;