From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Matthew Wilcox" <willy@infradead.org>,
"Christoph Hellwig" <hch@lst.de>,
linux-fsdevel@vger.kernel.org,
"Octavian Purdila" <octavian.purdila@intel.com>,
"Pantelis Antoniou" <pantelis.antoniou@konsulko.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Kai Mäkisara" <Kai.Makisara@kolumbus.fi>,
linux-scsi@vger.kernel.org
Subject: Re: [RFC] Re: broken userland ABI in configfs binary attributes
Date: Sat, 31 Aug 2019 10:32:41 +0200 [thread overview]
Message-ID: <20190831083241.GC28527@lst.de> (raw)
In-Reply-To: <20190826192819.GO1131@ZenIV.linux.org.uk>
On Mon, Aug 26, 2019 at 08:28:19PM +0100, Al Viro wrote:
> For configfs bin_attr it won't work, simply because it wants the entire
> thing to be present - callback parses the data. For SCSI tape... Maybe,
> but you'll need to take care of the overlaps with ->write(). Right now
> it can't happen (the last reference, about to be dropped right after
> st_flush() returns); if we do that on each ->flush(), we will have to
> cope with that fun and we'll need to keep an error (if any) for the
> next call of st_flush() to pick and return. I'm not saying it can't
> be done, but that's really a question for SCSI folks.
So for the one real life example of the configfs attribute life
actually is simpler. acpi_table_aml_write verifies early on that
the size matches what it expects. So if we document that any future
instance needs to be able to do that as well we should be able to
get away with just writing it from ->flush.
next prev parent reply other threads:[~2019-08-31 8:32 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 2:48 broken userland ABI in configfs binary attributes Al Viro
2019-08-26 16:29 ` [RFC] " Al Viro
2019-08-26 18:20 ` Matthew Wilcox
2019-08-26 19:28 ` Al Viro
2019-08-27 8:51 ` Miklos Szeredi
2019-08-27 11:58 ` Al Viro
2019-08-27 12:21 ` Miklos Szeredi
2019-08-27 12:53 ` Al Viro
2019-08-31 8:32 ` Christoph Hellwig [this message]
2019-08-31 13:35 ` Al Viro
2019-08-31 14:44 ` Christoph Hellwig
2019-08-31 15:58 ` Al Viro
2019-08-26 18:34 ` "Kai Mäkisara (Kolumbus)"
2019-08-26 19:32 ` Al Viro
2019-08-27 15:01 ` Boaz Harrosh
2019-08-27 17:27 ` Al Viro
2019-08-27 17:59 ` Boaz Harrosh
2019-08-29 22:22 ` Al Viro
2019-08-29 23:32 ` Al Viro
2019-08-30 4:10 ` Dave Chinner
2019-08-30 4:44 ` Al Viro
2019-08-31 8:28 ` Christoph Hellwig
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