From: Christoph Hellwig <hch@lst.de>
To: Josef Bacik <josef@toxicpanda.com>
Cc: hch@lst.de, viro@ZenIV.linux.org.uk,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
willy@infradead.org, kernel-team@fb.com
Subject: Re: [PATCH 1/6] proc: use vmalloc for our kernel buffer
Date: Tue, 1 Sep 2020 17:14:20 +0200 [thread overview]
Message-ID: <20200901151420.GA30709@lst.de> (raw)
In-Reply-To: <20200813210411.905010-2-josef@toxicpanda.com>
On Thu, Aug 13, 2020 at 05:04:06PM -0400, Josef Bacik wrote:
> Since
>
> sysctl: pass kernel pointers to ->proc_handler
>
> we have been pre-allocating a buffer to copy the data from the proc
> handlers into, and then copying that to userspace. The problem is this
> just blind kmalloc()'s the buffer size passed in from the read, which in
> the case of our 'cat' binary was 64kib. Order-4 allocations are not
> awesome, and since we can potentially allocate up to our maximum order,
> use vmalloc for these buffers.
Maybe the subject should read ".. also use vmalloc" as we still default
to kmalloc for small allocations?
Otherwise looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2020-09-01 17:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-13 21:04 [PATCH 0/6] Some buffer management fixes for proc Josef Bacik
2020-08-13 21:04 ` [PATCH 1/6] proc: use vmalloc for our kernel buffer Josef Bacik
2020-09-01 15:14 ` Christoph Hellwig [this message]
2020-08-13 21:04 ` [PATCH 2/6] tree-wide: rename vmemdup_user to kvmemdup_user Josef Bacik
2020-09-01 15:14 ` Christoph Hellwig
2020-08-13 21:04 ` [PATCH 3/6] proc: allocate count + 1 for our read buffer Josef Bacik
2020-09-01 15:14 ` Christoph Hellwig
2020-08-13 21:04 ` [PATCH 4/6] sysctl: make proc_put_long() use scnprintf Josef Bacik
2020-09-01 15:15 ` Christoph Hellwig
2020-08-13 21:04 ` [PATCH 5/6] parport: rework procfs handlers to take advantage of the new buffer Josef Bacik
2020-09-01 15:15 ` Christoph Hellwig
2020-08-13 21:04 ` [PATCH 6/6] sunrpc: rework proc " Josef Bacik
2020-09-01 15:15 ` Christoph Hellwig
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