On Thu 14-04-16 10:48:30, Toshi Kani wrote:
> +
> +/**
> + * dax_get_unmapped_area - handle get_unmapped_area for a DAX file
> + * @filp: The file being mmap'd, if not NULL
> + * @addr: The mmap address. If NULL, the kernel assigns the address
> + * @len: The mmap size in bytes
> + * @pgoff: The page offset in the file where the mapping starts from.
> + * @flags: The mmap flags
> + *
> + * This function can be called by a filesystem for get_unmapped_area().
> + * When a target file is a DAX file, it aligns the mmap address at the
> + * beginning of the file by the pmd size.
> + */
> +unsigned long dax_get_unmapped_area(struct file *filp, unsigned long addr,
> + unsigned long len, unsigned long pgoff, unsigned long flags)
> +{
> + unsigned long off, off_end, off_pmd, len_pmd, addr_pmd;
I think we need to use 'loff_t' for the offsets for things to work on
32-bits.
> + if (!IS_ENABLED(CONFIG_FS_DAX_PMD) ||
> + !filp || addr || !IS_DAX(filp->f_mapping->host))
> + goto out;
> +
> + off = pgoff << PAGE_SHIFT;
And here we need to type to loff_t before the shift...
> + off_end = off + len;
> + off_pmd = round_up(off, PMD_SIZE); /* pmd-aligned offset */
> +
> + if ((off_end <= off_pmd) || ((off_end - off_pmd) < PMD_SIZE))
None of these parenthesis is actually needed (and IMHO they make the code
less readable, not more).
> + goto out;
> +
> + len_pmd = len + PMD_SIZE;
> + if ((off + len_pmd) < off)
> + goto out;
> +
> + addr_pmd = current->mm->get_unmapped_area(filp, addr, len_pmd,
> + pgoff, flags);
> + if (!IS_ERR_VALUE(addr_pmd)) {
> + addr_pmd += (off - addr_pmd) & (PMD_SIZE - 1);
> + return addr_pmd;
Otherwise the patch looks good to me.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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