On Tue, Jun 07, 2022 at 04:54:29PM +0800, Shiyang Ruan wrote:
>
>
> 在 2022/6/7 15:59, Dan Carpenter 写道:
> > Hello Shiyang Ruan,
> >
> > The patch 1447ac26a964: "fsdax: output address in dax_iomap_pfn() and
> > rename it" from Jun 3, 2022, leads to the following Smatch static
> > checker warning:
> >
> > fs/dax.c:1085 dax_iomap_direct_access()
> > error: uninitialized symbol 'rc'.
> >
> > fs/dax.c
> > 1052 static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos,
> > 1053 size_t size, void **kaddr, pfn_t *pfnp)
> > 1054 {
> > 1055 pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
> > 1056 int id, rc;
> > 1057 long length;
> > 1058
> > 1059 id = dax_read_lock();
> > 1060 length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
> > 1061 DAX_ACCESS, kaddr, pfnp);
> > 1062 if (length < 0) {
> > 1063 rc = length;
> > 1064 goto out;
> > 1065 }
> > 1066 if (!pfnp)
> > 1067 goto out_check_addr;
> >
> > Is this an error path?
> >
> > 1068 rc = -EINVAL;
> > 1069 if (PFN_PHYS(length) < size)
> > 1070 goto out;
> > 1071 if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1))
> > 1072 goto out;
> > 1073 /* For larger pages we need devmap */
> > 1074 if (length > 1 && !pfn_t_devmap(*pfnp))
> > 1075 goto out;
> > 1076 rc = 0;
> > 1077
> > 1078 out_check_addr:
> > 1079 if (!kaddr)
> > 1080 goto out;
> >
> > How is it supposed to be handled if both "pfnp" and "kaddr" are NULL?
> >
> > Smatch says that "kaddr" can never be NULL so this code is just future
> > proofing but I didn't look at it carefully.
>
> Yes, we always pass the @kaddr in all caller, it won't be NULL now. And
> even @kaddr and @pfnp are both NULL, it won't cause any error. So, I think
> the rc should be initialized to 0 :
>
> {
> pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
> - int id, rc;
> + int id, rc = 0;
> long length;
>
> Do I need to fix this and resend a patch to the list? Or you could help me
> fix this?
Could you handle this? Is this in Andrew's tree? I think you send a
follow on patch and he'll eventually fold it into the original patch.
regards,
dan carpenter
