On Fri, Jun 01, 2018 at 06:58:46PM +1000, Stephen Rothwell wrote:
> Hi Dan,
>
> Today's linux-next merge of the nvdimm tree got a conflict in:
>
> drivers/dax/super.c
>
> between commits:
>
> ba23cba9b3bd ("fs: allow per-device dax status checking for filesystems")
> 80660f20252d ("dax: change bdev_dax_supported() to support boolean returns")
>
> from the xfs tree and commit:
>
> e76384884344 ("mm: introduce MEMORY_DEVICE_FS_DAX and
> CONFIG_DEV_PAGEMAP_OPS")
>
> from the nvdimm tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> --
> Cheers,
> Stephen Rothwell
> diff --cc drivers/dax/super.c
> index 1d7bd96511f0,88672b6f6252..000000000000
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@@ -80,11 -80,13 +80,12 @@@ EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev)
> * This is a library function for filesystems to check if the block device
> * can be mounted with dax option.
> *
> - * Return: negative errno if unsupported, 0 if supported.
> + * Return: true if supported, false if unsupported
> */
> -int __bdev_dax_supported(struct super_block *sb, int blocksize)
> +bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
> {
> - struct block_device *bdev = sb->s_bdev;
> struct dax_device *dax_dev;
> + bool dax_enabled = false;
> pgoff_t pgoff;
> int err, id;
> void *kaddr;
> @@@ -134,15 -135,22 +135,22 @@@
> * on being able to do (page_address(pfn_to_page())).
> */
> WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));
> + dax_enabled = true;
> } else if (pfn_t_devmap(pfn)) {
> - /* pass */;
> - } else {
> + struct dev_pagemap *pgmap;
> +
> + pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL);
> + if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX)
> + dax_enabled = true;
> + put_dev_pagemap(pgmap);
> + }
> +
> + if (!dax_enabled) {
> - pr_debug("VFS (%s): error: dax support not enabled\n",
> - sb->s_id);
> + pr_debug("%s: error: dax support not enabled\n",
> + bdevname(bdev, buf));
> - return false;
> + return -EOPNOTSUPP;
Hang on a sec, the changes in the xfs tree make this function return a
boolean (true for dax-is-supported, false for dax-not-supported), but
this change partially reverts the boolean return values.
> }
> -
> - return true;
> + return 0;
The merge should retain the 'return false' above and the 'return true'
here... or possibly just return dax_enabled:
if (!dax_enabled) {
pr_debug(...);
pr_debug(...);
}
return dax_enabled;
--D
> }
> EXPORT_SYMBOL_GPL(__bdev_dax_supported);
> #endif
