Re: [PATCH 03/17] fs: rename and move block_page_mkwrite_return

[Matthew Wilcox]

On Mon, Apr 24, 2023 at 07:49:12AM +0200, Christoph Hellwig wrote:
> block_page_mkwrite_return is neither block nor mkwrite specific, and
> should not be under CONFIG_BLOCK.  Move it to mm.h and rename it to
> errno_to_vmfault.

Could you move it about 300 lines down and put it near vmf_error()
so we think about how to unify the two at some point?

Perhaps it should better be called vmf_fs_error() for now since the
errnos it handles are the kind generated by filesystems.

> +++ b/include/linux/mm.h
> @@ -3061,6 +3061,19 @@ extern vm_fault_t filemap_map_pages(struct vm_fault *vmf,
>  		pgoff_t start_pgoff, pgoff_t end_pgoff);
>  extern vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf);
>  
> +/* Convert errno to return value from ->page_mkwrite() call */
> +static inline vm_fault_t errno_to_vmfault(int err)
> +{
> +	if (err == 0)
> +		return VM_FAULT_LOCKED;
> +	if (err == -EFAULT || err == -EAGAIN)
> +		return VM_FAULT_NOPAGE;
> +	if (err == -ENOMEM)
> +		return VM_FAULT_OOM;
> +	/* -ENOSPC, -EDQUOT, -EIO ... */
> +	return VM_FAULT_SIGBUS;
> +}
> +
>  extern unsigned long stack_guard_gap;