From: Christoph Hellwig <hch@infradead.org>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
Song Liu <song@kernel.org>, Christoph Hellwig <hch@infradead.org>,
Donald Buczek <buczek@molgen.mpg.de>,
Guoqing Jiang <guoqing.jiang@linux.dev>, Xiao Ni <xni@redhat.com>,
Stephen Bates <sbates@raithlin.com>,
Martin Oliveira <Martin.Oliveira@eideticom.com>,
David Sloan <David.Sloan@eideticom.com>
Subject: Re: [PATCH v2 12/17] md/raid5-cache: Move struct r5l_log definition to raid5-log.h
Date: Sun, 29 May 2022 22:59:11 -0700 [thread overview]
Message-ID: <YpRdL+2e7gngOYPa@infradead.org> (raw)
In-Reply-To: <20220526163604.32736-13-logang@deltatee.com>
On Thu, May 26, 2022 at 10:35:59AM -0600, Logan Gunthorpe wrote:
> Move struct r5l_log definition to raid5-log.h. While this reduces
> encapsulation, it is necessary for the definition of r5l_log to be
> public so that rcu_access_pointer() can be used on conf-log in the
> next patch.
>
> rcu_access_pointer(p) doesn't technically dereference the log pointer
> however, it does use typeof(*p) and some older GCC versions (anything
> earlier than gcc-10) will wrongly try to dereference the structure:
>
> include/linux/rcupdate.h:384:9: error: dereferencing pointer to
> incomplete type ‘struct r5l_log’
>
> typeof(*p) *local = (typeof(*p) *__force)READ_ONCE(p); \
> ^
>
> include/linux/rcupdate.h:495:31: note: in expansion of
> macro ‘__rcu_access_pointer’
>
> #define rcu_access_pointer(p) __rcu_access_pointer((p),
> __UNIQUE_ID(rcu), __rcu)
>
> To prevent this, simply provide the definition where
> rcu_access_pointer() may be used.
What about just moving any code that does the rcu_access_pointer on
conf->log to raid5-cache.c and doing an out of line call for it
instead?
next prev parent reply other threads:[~2022-05-30 5:59 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-26 16:35 [PATCH v2 00/17] Bug fixes for mdadm tests Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 01/17] md/raid5-log: Drop extern decorators for function prototypes Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 02/17] md/raid5-cache: Add r5c_conf_is_writeback() helper Logan Gunthorpe
2022-05-30 5:56 ` Christoph Hellwig
2022-05-26 16:35 ` [PATCH v2 03/17] md/raid5-cache: Refactor r5l_start() to take a struct r5conf Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 04/17] md/raid5-cache: Refactor r5l_flush_stripe_to_raid() " Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 05/17] md/raid5-cache: Refactor r5l_wake_reclaim() " Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 06/17] md/raid5-cache: Refactor remaining functions to take a r5conf Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 07/17] md/raid5-ppl: Drop unused argument from ppl_handle_flush_request() Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 08/17] md/raid5-cache: Pass the log through to r5c_finish_cache_stripe() Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 09/17] md/raid5-cache: Don't pass conf to r5c_calculate_new_cp() Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 10/17] md/raid5-cache: Take struct r5l_log in r5c_log_required_to_flush_cache() Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 11/17] md/raid5: Ensure array is suspended for calls to log_exit() Logan Gunthorpe
2022-05-26 16:35 ` [PATCH v2 12/17] md/raid5-cache: Move struct r5l_log definition to raid5-log.h Logan Gunthorpe
2022-05-30 5:59 ` Christoph Hellwig [this message]
2022-05-30 15:48 ` Logan Gunthorpe
2022-06-01 22:36 ` Song Liu
2022-06-01 22:42 ` Logan Gunthorpe
2022-06-01 22:50 ` Song Liu
2022-05-26 16:36 ` [PATCH v2 13/17] md/raid5-cache: Add RCU protection to conf->log accesses Logan Gunthorpe
2022-05-30 6:01 ` Christoph Hellwig
2022-05-30 15:57 ` Logan Gunthorpe
2022-05-26 16:36 ` [PATCH v2 14/17] md/raid5-cache: Annotate pslot with __rcu notation Logan Gunthorpe
2022-05-26 16:36 ` [PATCH v2 15/17] md: Use enum for overloaded magic numbers used by mddev->curr_resync Logan Gunthorpe
2022-05-30 6:01 ` Christoph Hellwig
2022-05-30 15:43 ` Logan Gunthorpe
2022-05-26 16:36 ` [PATCH v2 16/17] md: Ensure resync is reported after it starts Logan Gunthorpe
2022-05-30 6:02 ` Christoph Hellwig
2022-05-26 16:36 ` [PATCH v2 17/17] md: Notify sysfs sync_completed in md_reap_sync_thread() Logan Gunthorpe
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