Messages in this thread |  | | From | Roman Kiryanov <> | Date | Mon, 13 Aug 2018 20:47:54 -0700 | Subject | Re: [PATCH 6/9] platform: goldfish: pipe: Fail compilation if structs are too large |
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Hi,
thank you for reviewing my patches. I decided to put BUILD_BUG_ON close to places where it is important that these structs fit into a memory page to give some context.
Regards, Roman. On Mon, Aug 13, 2018 at 6:48 PM Joe Perches <joe@perches.com> wrote: > > On Mon, 2018-08-13 at 16:38 -0700, rkir@google.com wrote: > > From: Roman Kiryanov <rkir@google.com> > > > > Since the driver provides no workaround prevent in cases if structs do > > no fit into a memory page, it is better to fail complation to find about > > the issue earlt instead of returning errors at runtime. > > Minor earlt/early typo > > > diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c > [] > > @@ -797,9 +798,7 @@ static int goldfish_pipe_device_init(struct platform_device *pdev) > > * needs to be contained in a single physical page. The easiest choice > > * is to just allocate a page and place the buffers in it. > > */ > > - if (WARN_ON(sizeof(*dev->buffers) > PAGE_SIZE)) > > - return -ENOMEM; > > - > > + BUILD_BUG_ON(sizeof(*dev->buffers) > PAGE_SIZE); > > page = (char *)__get_free_page(GFP_KERNEL); > > if (!page) { > > kfree(dev->pipes); > > @@ -842,8 +841,7 @@ static int goldfish_pipe_probe(struct platform_device *pdev) > > struct resource *r; > > struct goldfish_pipe_dev *dev = pipe_dev; > > > > - if (WARN_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE)) > > - return -ENOMEM; > > + BUILD_BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE); > > > > /* not thread safe, but this should not happen */ > > WARN_ON(dev->base != NULL); > > Why separate these BUILD_BUG_ONs into 2 different functions? > > Why not just > BUILD_BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE); > BUILD_BUG_ON(sizeof(struct goldfish_pipe_dev_buffers) > PAGE_SIZE); >
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