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md/bitmap: use set_bit, test_bit, etc for operation on bitmap->flags.
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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>
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NeilBrown committed May 22, 2012
1 parent 84e9234 commit b405fe9
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Showing 2 changed files with 24 additions and 28 deletions.
46 changes: 21 additions & 25 deletions drivers/md/bitmap.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 {

Expand All @@ -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);
}
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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);
Expand All @@ -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;
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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));
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
Expand All @@ -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;
Expand Down
6 changes: 3 additions & 3 deletions drivers/md/bitmap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand Down

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