On 2024-10-31 01:22, Ming Lei wrote:
On Thu, Oct 31, 2024 at 08:14:49AM +0800, Ming Lei wrote:
On Wed, Oct 30, 2024 at 06:56:48PM +0100, Klara Modin wrote:
Hi,
On 2024-10-24 07:00, Christoph Hellwig wrote:
From: Ming Lei <ming.lei@xxxxxxxxxx>
The iov_iter_extract_pages interface allows to return physically
discontiguous pages, as long as all but the first and last page
in the array are page aligned and page size. Rewrite
iov_iter_extract_bvec_pages to take advantage of that instead of only
returning ranges of physically contiguous pages.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
[hch: minor cleanups, new commit log]
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
With this patch (e4e535bff2bc82bb49a633775f9834beeaa527db in next-20241030),
I'm unable to connect via nvme-tcp with this in the log:
nvme nvme1: failed to send request -5
nvme nvme1: Connect command failed: host path error
nvme nvme1: failed to connect queue: 0 ret=880
With the patch reverted it works as expected:
nvme nvme1: creating 24 I/O queues.
nvme nvme1: mapped 24/0/0 default/read/poll queues.
nvme nvme1: new ctrl: NQN
"nqn.2018-06.eu.kasm.int:freenas:backup:parmesan.int.kasm.eu", addr
[2001:0678:0a5c:1204:6245:cbff:fe9c:4f59]:4420, hostnqn:
nqn.2018-06.eu.kasm.int:parmesan
I can't reproduce it by running blktest 'nvme_trtype=tcp ./check nvme/'
on both next tree & for-6.13/block.
Can you collect the following bpftrace log by running the script before
connecting to nvme-tcp?
I didn't seem to get any output from the bpftrace script (I confirmed
that I had the config as you requested, but I'm not very familiar with
bpftrace so I could have done something wrong). I could, however,
reproduce the issue in qemu and added breakpoints on
nvmf_connect_io_queue and iov_iter_extract_pages. The breakpoint on
iov_iter_extract_pages got hit once when running nvme connect:
(gdb) break nvmf_connect_io_queue
Breakpoint 1 at 0xffffffff81a5d960: file
/home/klara/git/linux/drivers/nvme/host/fabrics.c, line 525.
(gdb) break iov_iter_extract_pages
Breakpoint 2 at 0xffffffff817633b0: file
/home/klara/git/linux/lib/iov_iter.c, line 1900.
(gdb) c
Continuing.
[Switching to Thread 1.1]
Thread 1 hit Breakpoint 2, iov_iter_extract_pages
(i=i@entry=0xffffc900001ebd68,
pages=pages@entry=0xffffc900001ebb08, maxsize=maxsize@entry=72,
maxpages=8,
extraction_flags=extraction_flags@entry=0,
offset0=offset0@entry=0xffffc900001ebb10)
at /home/klara/git/linux/lib/iov_iter.c:1900
1900 {
(gdb) print i->count
$5 = 72
(gdb) print i->iov_offset
$6 = 0
(gdb) print i->bvec->bv_offset
$7 = 3952
(gdb) print i->bvec->bv_len
$8 = 72
(gdb) c
Continuing.
I didn't hit the breakpoint in nvmf_connect_io_queue, but I instead hit
it if I add it to nvmf_connect_admin_queue. I added this function to the
bpftrace script but that didn't produce any output either.
And please try the following patch:
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 9fc06f5fb748..c761f6db3cb4 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1699,6 +1699,7 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i,
i->bvec++;
skip = 0;
}
+ bi.bi_idx = 0;
bi.bi_size = maxsize + skip;
bi.bi_bvec_done = skip;
Applying this seems to fix the problem.
Thanks,
Klara Modin
Thanks,
Ming
