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author | Jens Axboe <axboe@kernel.dk> | 2021-10-28 16:57:09 +0200 |
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committer | Jens Axboe <axboe@kernel.dk> | 2021-12-03 22:51:29 +0100 |
commit | ceaa762527f41a431b552bc000de4b626d2d8cb7 (patch) | |
tree | 74e9ff872d0cbfe0373c25edb60840d77b06c245 /block | |
parent | mm: move filemap_range_needs_writeback() into header (diff) | |
download | linux-ceaa762527f41a431b552bc000de4b626d2d8cb7.tar.xz linux-ceaa762527f41a431b552bc000de4b626d2d8cb7.zip |
block: move direct_IO into our own read_iter handler
Don't call into generic_file_read_iter() if we know it's O_DIRECT, just
set it up ourselves and call our own handler. This avoids an indirect call
for O_DIRECT.
Fall back to filemap_read() if we fail.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r-- | block/fops.c | 37 |
1 files changed, 32 insertions, 5 deletions
diff --git a/block/fops.c b/block/fops.c index ad732a36f9b3..4d0e220f379e 100644 --- a/block/fops.c +++ b/block/fops.c @@ -566,21 +566,48 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct block_device *bdev = iocb->ki_filp->private_data; loff_t size = bdev_nr_bytes(bdev); + size_t count = iov_iter_count(to); loff_t pos = iocb->ki_pos; size_t shorted = 0; - ssize_t ret; + ssize_t ret = 0; - if (unlikely(pos + iov_iter_count(to) > size)) { + if (unlikely(pos + count > size)) { if (pos >= size) return 0; size -= pos; - if (iov_iter_count(to) > size) { - shorted = iov_iter_count(to) - size; + if (count > size) { + shorted = count - size; iov_iter_truncate(to, size); } } - ret = generic_file_read_iter(iocb, to); + if (iocb->ki_flags & IOCB_DIRECT) { + struct address_space *mapping = iocb->ki_filp->f_mapping; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_needs_writeback(mapping, iocb->ki_pos, + iocb->ki_pos + count - 1)) + return -EAGAIN; + } else { + ret = filemap_write_and_wait_range(mapping, + iocb->ki_pos, + iocb->ki_pos + count - 1); + if (ret < 0) + return ret; + } + + file_accessed(iocb->ki_filp); + + ret = blkdev_direct_IO(iocb, to); + if (ret >= 0) { + iocb->ki_pos += ret; + count -= ret; + } + if (ret < 0 || !count) + return ret; + } + + ret = filemap_read(iocb, to, ret); if (unlikely(shorted)) iov_iter_reexpand(to, iov_iter_count(to) + shorted); |