From fac7c6d529acf2b5428ad08c1b1127e29e570790 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 13 Oct 2021 09:57:11 +0100 Subject: [PATCH] block: cache bdev in struct file for raw bdev IO bdev = &BDEV_I(file->f_mapping->host)->bdev Getting struct block_device from a file requires 2 memory dereferences as illustrated above, that takes a toll on performance, so cache it in yet unused file->private_data. That gives a noticeable peak performance improvement. Signed-off-by: Pavel Begunkov Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/8415f9fe12e544b9da89593dfbca8de2b52efe03.1634115360.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- block/fops.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/block/fops.c b/block/fops.c index ce12555..551b71af 100644 --- a/block/fops.c +++ b/block/fops.c @@ -17,7 +17,7 @@ #include #include "blk.h" -static struct inode *bdev_file_inode(struct file *file) +static inline struct inode *bdev_file_inode(struct file *file) { return file->f_mapping->host; } @@ -54,8 +54,7 @@ static void blkdev_bio_end_io_simple(struct bio *bio) static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, unsigned int nr_pages) { - struct file *file = iocb->ki_filp; - struct block_device *bdev = I_BDEV(bdev_file_inode(file)); + struct block_device *bdev = iocb->ki_filp->private_data; struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; loff_t pos = iocb->ki_pos; bool should_dirty = false; @@ -183,9 +182,7 @@ static void blkdev_bio_end_io(struct bio *bio) static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, unsigned int nr_pages) { - struct file *file = iocb->ki_filp; - struct inode *inode = bdev_file_inode(file); - struct block_device *bdev = I_BDEV(inode); + struct block_device *bdev = iocb->ki_filp->private_data; struct blk_plug plug; struct blkdev_dio *dio; struct bio *bio; @@ -389,8 +386,7 @@ static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) { - struct inode *bd_inode = bdev_file_inode(filp); - struct block_device *bdev = I_BDEV(bd_inode); + struct block_device *bdev = filp->private_data; int error; error = file_write_and_wait_range(filp, start, end); @@ -432,6 +428,8 @@ static int blkdev_open(struct inode *inode, struct file *filp) bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp); if (IS_ERR(bdev)) return PTR_ERR(bdev); + + filp->private_data = bdev; filp->f_mapping = bdev->bd_inode->i_mapping; filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); return 0; @@ -439,7 +437,7 @@ static int blkdev_open(struct inode *inode, struct file *filp) static int blkdev_close(struct inode *inode, struct file *filp) { - struct block_device *bdev = I_BDEV(bdev_file_inode(filp)); + struct block_device *bdev = filp->private_data; blkdev_put(bdev, filp->f_mode); return 0; @@ -454,14 +452,14 @@ static int blkdev_close(struct inode *inode, struct file *filp) */ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) { - struct file *file = iocb->ki_filp; - struct inode *bd_inode = bdev_file_inode(file); + struct block_device *bdev = iocb->ki_filp->private_data; + struct inode *bd_inode = bdev->bd_inode; loff_t size = i_size_read(bd_inode); struct blk_plug plug; size_t shorted = 0; ssize_t ret; - if (bdev_read_only(I_BDEV(bd_inode))) + if (bdev_read_only(bdev)) return -EPERM; if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) @@ -493,9 +491,8 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) { - struct file *file = iocb->ki_filp; - struct inode *bd_inode = bdev_file_inode(file); - loff_t size = i_size_read(bd_inode); + struct block_device *bdev = iocb->ki_filp->private_data; + loff_t size = i_size_read(bdev->bd_inode); loff_t pos = iocb->ki_pos; size_t shorted = 0; ssize_t ret; -- 2.7.4