md/bitmap: use set_bit, test_bit, etc for operation on bitmap->flags.

We currently use '&' and '|' which isn't the norm in the kernel
and doesn't allow easy atomicity.
So change to bit numbers and {set,clear,test}_bit.
This allows us to remove a spinlock/unlock (which was dubious anyway)
and some other simplifications.

Signed-off-by: NeilBrown <neilb@suse.de>

2 files changed, 24 insertions, 28 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 09d360ff77dc..f3a9dffc3fc8 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -271,7 +271,7 @@ static void write_page(struct bitmap *bitmap, struct page *page, int wait)
         if (bitmap->storage.file == NULL) {
                 switch (write_sb_page(bitmap, page, wait)) {
                 case -EINVAL:
-                        bitmap->flags |= BITMAP_WRITE_ERROR;
+                        set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
                 }
         } else {
 
@@ -289,20 +289,16 @@ static void write_page(struct bitmap *bitmap, struct page *page, int wait)
                         wait_event(bitmap->write_wait,
                                    atomic_read(&bitmap->pending_writes)==0);
         }
-        if (bitmap->flags & BITMAP_WRITE_ERROR)
+        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
                 bitmap_file_kick(bitmap);
 }
 
 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 {
         struct bitmap *bitmap = bh->b_private;
-        unsigned long flags;
 
-        if (!uptodate) {
-                spin_lock_irqsave(&bitmap->lock, flags);
-                bitmap->flags |= BITMAP_WRITE_ERROR;
-                spin_unlock_irqrestore(&bitmap->lock, flags);
-        }
+        if (!uptodate)
+                set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
         if (atomic_dec_and_test(&bitmap->pending_writes))
                 wake_up(&bitmap->write_wait);
 }
@@ -389,7 +385,7 @@ static int read_page(struct file *file, unsigned long index,
 
         wait_event(bitmap->write_wait,
                    atomic_read(&bitmap->pending_writes)==0);
-        if (bitmap->flags & BITMAP_WRITE_ERROR)
+        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
                 ret = -EIO;
 out:
         if (ret)
@@ -521,7 +517,7 @@ static int bitmap_new_disk_sb(struct bitmap *bitmap)
 
         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 
-        bitmap->flags |= BITMAP_STALE;
+        set_bit(BITMAP_STALE, &bitmap->flags);
         sb->state = cpu_to_le32(bitmap->flags);
         bitmap->events_cleared = bitmap->mddev->events;
         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
@@ -545,7 +541,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
                 chunksize = 128 * 1024 * 1024;
                 daemon_sleep = 5 * HZ;
                 write_behind = 0;
-                bitmap->flags = BITMAP_STALE;
+                set_bit(BITMAP_STALE, &bitmap->flags);
                 err = 0;
                 goto out_no_sb;
         }
@@ -617,20 +613,20 @@ static int bitmap_read_sb(struct bitmap *bitmap)
                                "-- forcing full recovery\n",
                                bmname(bitmap), events,
                                (unsigned long long) bitmap->mddev->events);
-                        bitmap->flags |= BITMAP_STALE;
+                        set_bit(BITMAP_STALE, &bitmap->flags);
                 }
         }
 
         /* assign fields using values from superblock */
         bitmap->flags |= le32_to_cpu(sb->state);
         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
-                bitmap->flags |= BITMAP_HOSTENDIAN;
+                set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
         err = 0;
 out:
         kunmap_atomic(sb);
 out_no_sb:
-        if (bitmap->flags & BITMAP_STALE)
+        if (test_bit(BITMAP_STALE, &bitmap->flags))
                 bitmap->events_cleared = bitmap->mddev->events;
         bitmap->mddev->bitmap_info.chunksize = chunksize;
         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
@@ -796,8 +792,7 @@ static void bitmap_file_kick(struct bitmap *bitmap)
 {
         char *path, *ptr = NULL;
 
-        if (!(bitmap->flags & BITMAP_STALE)) {
-                bitmap->flags |= BITMAP_STALE;
+        if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
                 bitmap_update_sb(bitmap);
 
                 if (bitmap->storage.file) {
@@ -868,7 +863,7 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 
         /* set the bit */
         kaddr = kmap_atomic(page);
-        if (bitmap->flags & BITMAP_HOSTENDIAN)
+        if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
                 set_bit(bit, kaddr);
         else
                 __set_bit_le(bit, kaddr);
@@ -890,7 +885,7 @@ static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
                 return;
         bit = file_page_offset(&bitmap->storage, chunk);
         paddr = kmap_atomic(page);
-        if (bitmap->flags & BITMAP_HOSTENDIAN)
+        if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
                 clear_bit(bit, paddr);
         else
                 __clear_bit_le(bit, paddr);
@@ -941,7 +936,7 @@ void bitmap_unplug(struct bitmap *bitmap)
                 else
                         md_super_wait(bitmap->mddev);
         }
-        if (bitmap->flags & BITMAP_WRITE_ERROR)
+        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
                 bitmap_file_kick(bitmap);
 }
 EXPORT_SYMBOL(bitmap_unplug);
@@ -988,7 +983,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                 return 0;
         }
 
-        outofdate = bitmap->flags & BITMAP_STALE;
+        outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
         if (outofdate)
                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
                         "recovery\n", bmname(bitmap));
@@ -1045,12 +1040,13 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                 write_page(bitmap, page, 1);
 
                                 ret = -EIO;
-                                if (bitmap->flags & BITMAP_WRITE_ERROR)
+                                if (test_bit(BITMAP_WRITE_ERROR,
+                                             &bitmap->flags))
                                         goto err;
                         }
                 }
                 paddr = kmap_atomic(page);
-                if (bitmap->flags & BITMAP_HOSTENDIAN)
+                if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
                         b = test_bit(bit, paddr);
                 else
                         b = test_bit_le(bit, paddr);
@@ -1758,7 +1754,7 @@ int bitmap_create(struct mddev *mddev)
         mddev->bitmap = bitmap;
 
 
-        return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
+        return test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
 
  error:
         bitmap_free(bitmap);
@@ -1799,7 +1795,7 @@ int bitmap_load(struct mddev *mddev)
 
         if (err)
                 goto out;
-        bitmap->flags &= ~BITMAP_STALE;
+        clear_bit(BITMAP_STALE, &bitmap->flags);
 
         /* Kick recovery in case any bits were set */
         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
@@ -1809,7 +1805,7 @@ int bitmap_load(struct mddev *mddev)
 
         bitmap_update_sb(bitmap);
 
-        if (bitmap->flags & BITMAP_WRITE_ERROR)
+        if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
                 err = -EIO;
 out:
         return err;
diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
index 26689260e179..e2d999a62ba9 100644
--- a/drivers/md/bitmap.h
+++ b/drivers/md/bitmap.h
@@ -111,9 +111,9 @@ typedef __u16 bitmap_counter_t;
 
 /* use these for bitmap->flags and bitmap->sb->state bit-fields */
 enum bitmap_state {
-        BITMAP_STALE  = 0x002,  /* the bitmap file is out of date or had -EIO */
-        BITMAP_WRITE_ERROR = 0x004, /* A write error has occurred */
-        BITMAP_HOSTENDIAN = 0x8000,
+        BITMAP_STALE       = 1,  /* the bitmap file is out of date or had -EIO */
+        BITMAP_WRITE_ERROR = 2, /* A write error has occurred */
+        BITMAP_HOSTENDIAN  =15,
 };
 
 /* the superblock at the front of the bitmap file -- little endian */