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.
1081 if (!*kaddr)
1082 rc = -EFAULT;
1083 out:
1084 dax_read_unlock(id);
--> 1085 return rc;
1086 }
regards,
dan carpenter
