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authorAndi Kleen <ak@linux.intel.com>2012-01-12 17:20:34 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:12 -0800
commit87192a2a49c475cf322cb143e0fa63b0102d8567 (patch)
tree70acf2fb1e4a9a3a62559ad9218278d2fb114599
parentae55e1aaa7e2e57e538cb98cf617f511c5dc4f73 (diff)
vfs: cache request_queue in struct block_device
This makes it possible to get from the inode to the request_queue with one less cache miss. Used in followon optimization. The livetime of the pointer is the same as the gendisk. This assumes that the queue will always stay the same in the gendisk while it's visible to block_devices. I think that's safe correct? Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/block_dev.c3
-rw-r--r--include/linux/fs.h2
2 files changed, 5 insertions, 0 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index afe74dda632..0e575d1304b 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1139,6 +1139,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
mutex_lock_nested(&bdev->bd_mutex, for_part);
if (!bdev->bd_openers) {
bdev->bd_disk = disk;
+ bdev->bd_queue = disk->queue;
bdev->bd_contains = bdev;
if (!partno) {
struct backing_dev_info *bdi;
@@ -1159,6 +1160,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
disk_put_part(bdev->bd_part);
bdev->bd_part = NULL;
bdev->bd_disk = NULL;
+ bdev->bd_queue = NULL;
mutex_unlock(&bdev->bd_mutex);
disk_unblock_events(disk);
put_disk(disk);
@@ -1232,6 +1234,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
disk_put_part(bdev->bd_part);
bdev->bd_disk = NULL;
bdev->bd_part = NULL;
+ bdev->bd_queue = NULL;
bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info);
if (bdev != bdev->bd_contains)
__blkdev_put(bdev->bd_contains, mode, 1);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e694bd4434a..4bc8169fb5a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -660,6 +660,7 @@ struct address_space {
* must be enforced here for CRIS, to let the least significant bit
* of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
*/
+struct request_queue;
struct block_device {
dev_t bd_dev; /* not a kdev_t - it's a search key */
@@ -682,6 +683,7 @@ struct block_device {
unsigned bd_part_count;
int bd_invalidated;
struct gendisk * bd_disk;
+ struct request_queue * bd_queue;
struct list_head bd_list;
/*
* Private data. You must have bd_claim'ed the block_device