From: Minwoo Im <minwoo.im.dev@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
Jens Axboe <axboe@fb.com>,
linux-nvme@lists.infradead.org, Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [RFC] nvme: set block size during namespace validation
Date: Thu, 24 Dec 2020 01:16:50 +0900 [thread overview]
Message-ID: <20201223161650.GA13354@localhost.localdomain> (raw)
In-Reply-To: <20201223154904.GA5967@lst.de>
Hello,
On 20-12-23 16:49:04, Christoph Hellwig wrote:
> set_blocksize just sets the block sise used for buffer heads and should
> not be called by the driver. blkdev_get updates the block size, so
> you must already have the fd re-reading the partition table open?
> I'm not entirely sure how we can work around this except by avoiding
> buffer head I/O in the partition reread code. Note that this affects
> all block drivers where the block size could change at runtime.
Thank you Christoph for your comment on this.
Agreed. BLKRRPART leads us to block_read_full_page which takes buffer
heads for I/O.
Yes, __blkdev_get() sets i_blkbits of block device inode via
set_init_blocksize. And Yes again as nvme-cli already opened the block
device fd and requests the BLKRRPART with that fd. Also, __bdev_get()
only updates the i_blkbits(blocksize) in case bdev->bd_openers == 0 which
is the first time to open this block device.
Then, how about having NVMe driver prevent underflow case for the
request->__data_len is smaller than the logical block size like:
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index ce1b61519441..030353d203bf 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -803,7 +803,11 @@ static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
cmnd->rw.opcode = op;
cmnd->rw.nsid = cpu_to_le32(ns->head->ns_id);
cmnd->rw.slba = cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
- cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
+
+ if (unlikely(blk_rq_bytes(req) < (1 << ns->lba_shift)))
+ cmnd->rw.length = 0;
+ else
+ cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
if (req_op(req) == REQ_OP_WRITE && ctrl->nr_streams)
nvme_assign_write_stream(ctrl, req, &control, &dsmgmt);
Thanks,
_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2020-12-23 16:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 15:01 [RFC] nvme: set block size during namespace validation Minwoo Im
2020-12-23 15:49 ` Christoph Hellwig
2020-12-23 16:16 ` Minwoo Im [this message]
2020-12-23 16:27 ` Christoph Hellwig
2020-12-23 18:31 ` Minwoo Im
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201223161650.GA13354@localhost.localdomain \
--to=minwoo.im.dev@gmail.com \
--cc=axboe@fb.com \
--cc=hch@lst.de \
--cc=kbusch@kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=sagi@grimberg.me \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).