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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 <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/8415f9fe12e544b9da89593dfbca8de2b52efe03.1634115360.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-10-13 09:57:11 +01:00 committed by Jens Axboe
parent c712dccc64
commit fac7c6d529
1 changed files with 12 additions and 15 deletions
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27
block/fops.c
View File

@ -17,7 +17,7 @@
#include <linux/fs.h>
#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;