Messages in this thread | | | Date | Wed, 14 May 2008 18:38:37 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/2] mtd: mtdchar.c silence sparse warning |
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On Wed, 14 May 2008 18:22:10 -0700 Harvey Harrison <harvey.harrison@gmail.com> wrote:
> The copy_to_user was casting away the address space to get the offset > of the length member. Use offsetof() instead and add it to the void __user *argp. > > drivers/mtd/mtdchar.c:527:23: warning: cast removes address space of expression > drivers/mtd/mtdchar.c:527:23: warning: incorrect type in argument 1 (different address spaces) > drivers/mtd/mtdchar.c:527:23: expected void [noderef] <asn:1>*to > drivers/mtd/mtdchar.c:527:23: got unsigned int *<noident> > > Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> > --- > drivers/mtd/mtdchar.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c > index 5d3ac51..3522d4a 100644 > --- a/drivers/mtd/mtdchar.c > +++ b/drivers/mtd/mtdchar.c > @@ -524,7 +524,7 @@ static int mtd_ioctl(struct inode *inode, struct file *file, > if (ops.oobretlen > 0xFFFFFFFFU) > ret = -EOVERFLOW; > retlen = ops.oobretlen; > - if (copy_to_user(&((struct mtd_oob_buf *)argp)->length, > + if (copy_to_user(argp + offsetof(struct mtd_oob_buf, length), > &retlen, sizeof(buf.length))) > ret = -EFAULT;
Cleaner would be:
struct mtd_oob_buf __user *user_mtd_oob_buf = argp;
if (copy_to_user(&user_mtd_oob_buf->length, ...
?
(cleaner, faster and shorter would be put_user(), but that's off-topic).
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