scsi/sd: remove big kernel lock
Every user of the BKL in the sd driver is the
result of the pushdown from the block layer
into the open/close/ioctl functions.
The only place that used to rely on the BKL is
the sdkp->openers variable, which gets converted
into an atomic_t.
Nothing else seems to rely on the BKL, since the
functions do not touch global data without holding
another lock, and the open/close functions are
still protected from concurrent execution using
the bdev->bd_mutex.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-scsi@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 43d3caf..f81a930 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -47,7 +47,7 @@
struct scsi_device *device;
struct device dev;
struct gendisk *disk;
- unsigned int openers; /* protected by BKL for now, yuck */
+ atomic_t openers;
sector_t capacity; /* size in 512-byte sectors */
u32 index;
unsigned short hw_sector_size;