[PATCH] nvme: core: don't hold rcu read lock in nvme_ns_chr_uring_cmd_iopoll

[Kanchan Joshi]

On Wed, Aug 09, 2023 at 03:53:35PM +0800, Ming Lei wrote:
>On Wed, Aug 09, 2023 at 12:29:20PM +0530, Kanchan Joshi wrote:
>> On Wed, Aug 09, 2023 at 10:04:40AM +0800, Ming Lei wrote:
>> > Now nvme_ns_chr_uring_cmd_iopoll() has switched to request based io
>> > polling, and the associated NS is guaranteed to be live in case of
>> > io polling, so request is guaranteed to be valid because blk-mq uses
>> > pre-allocated request pool.
>> >
>> > Remove the rcu read lock in nvme_ns_chr_uring_cmd_iopoll(), which
>> > isn't needed any more after switching to request based io polling.
>>
>> > Fix "BUG: sleeping function called from invalid context" because
>> > set_page_dirty_lock() from blk_rq_unmap_user() may sleep.
>> >
>> > Fixes: 585079b6e425 ("nvme: wire up async polling for io passthrough commands")
>> > Reported-by: Guangwu Zhang <guazhang at redhat.com>
>>
>> Thanks Ming. Looks fine, but any link to this report?
>> I don't see this breaking in my tests. So I wonder how to reproduce and
>> improve the coverage.
>
>It is reported in RH BZ2227639, and follows the stack trace:

Tried to access, but no luck.
Any chance that steps can be posted here?