diff options
| author | Jane Chu <jane.chu@oracle.com> | 2023-06-15 12:13:25 -0600 |
|---|---|---|
| committer | Vishal Verma <vishal.l.verma@intel.com> | 2023-06-26 07:54:23 -0600 |
| commit | 1ea7ca1b090145519aad998679222f0a14ab8fce (patch) | |
| tree | fb2db2940309adf5d9a477fdfe742af55ad710c0 /include/linux/dax.h | |
| parent | 95bf6df03d412f678a7b558da186c2ef797ac40c (diff) | |
dax: enable dax fault handler to report VM_FAULT_HWPOISON
When multiple processes mmap() a dax file, then at some point,
a process issues a 'load' and consumes a hwpoison, the process
receives a SIGBUS with si_code = BUS_MCEERR_AR and with si_lsb
set for the poison scope. Soon after, any other process issues
a 'load' to the poisoned page (that is unmapped from the kernel
side by memory_failure), it receives a SIGBUS with
si_code = BUS_ADRERR and without valid si_lsb.
This is confusing to user, and is different from page fault due
to poison in RAM memory, also some helpful information is lost.
Channel dax backend driver's poison detection to the filesystem
such that instead of reporting VM_FAULT_SIGBUS, it could report
VM_FAULT_HWPOISON.
If user level block IO syscalls fail due to poison, the errno will
be converted to EIO to maintain block API consistency.
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Link: https://lore.kernel.org/r/20230615181325.1327259-2-jane.chu@oracle.com
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Diffstat (limited to 'include/linux/dax.h')
| -rw-r--r-- | include/linux/dax.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/dax.h b/include/linux/dax.h index bf6258472e49..261944ec0887 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -261,6 +261,19 @@ static inline bool dax_mapping(struct address_space *mapping) return mapping->host && IS_DAX(mapping->host); } +/* + * Due to dax's memory and block duo personalities, hwpoison reporting + * takes into consideration which personality is presently visible. + * When dax acts like a block device, such as in block IO, an encounter of + * dax hwpoison is reported as -EIO. + * When dax acts like memory, such as in page fault, a detection of hwpoison + * is reported as -EHWPOISON which leads to VM_FAULT_HWPOISON. + */ +static inline int dax_mem2blk_err(int err) +{ + return (err == -EHWPOISON) ? -EIO : err; +} + #ifdef CONFIG_DEV_DAX_HMEM_DEVICES void hmem_register_resource(int target_nid, struct resource *r); #else |