On Mon, 25 Nov 2013 16:22:31 +0000 "Jan Beulich" <jbeul...@suse.com> wrote:
> Commit fad1a86e ("procfs: call default get_unmapped_area on MMU-present
> architectures"), as its title says, took care of only the MMU case,
> leaving the !MMU side still in the regressed state (returning -EIO in
> all cases where pde->proc_fops->get_unmapped_area is NULL).
The changelog is rather mystifying unless the reader goes off and finds
the fad1a86e changelog, so let's do that for them by adding this:
>From the fad1a86e changelog:
: Commit c4fe24485729 ("sparc: fix PCI device proc file mmap(2)") added
: proc_reg_get_unmapped_area in proc_reg_file_ops and
: proc_reg_file_ops_no_compat, by which now mmap always returns EIO if
: get_unmapped_area method is not defined for the target procfs file, which
: causes regression of mmap on /proc/vmcore.
:
: To address this issue, like get_unmapped_area(), call default
: current->mm->get_unmapped_area on MMU-present architectures if
: pde->proc_fops->get_unmapped_area, i.e. the one in actual file operation
: in the procfs file, is not defined.
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
> Cc: HATAYAMA Daisuke <d.hatay...@jp.fujitsu.com>
> Cc: Alexey Dobriyan <adobri...@gmail.com>
> Cc: David S. Miller <da...@davemloft.net>
I tagged this with
Cc: <sta...@vger.kernel.org> [3.12.x]
OK?
> +++ 3.13-rc1-proc-get-unmapped-area/fs/proc/inode.c
> @@ -292,16 +292,19 @@ proc_reg_get_unmapped_area(struct file *
> {
> struct proc_dir_entry *pde = PDE(file_inode(file));
> unsigned long rv = -EIO;
> - unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
> - unsigned long, unsigned long) = NULL;
> +
> if (use_pde(pde)) {
> + typeof(proc_reg_get_unmapped_area) *get_area
> #ifdef CONFIG_MMU
> - get_area = current->mm->get_unmapped_area;
> + = pde->proc_fops->get_unmapped_area
> + ?: current->mm->get_unmapped_area;
> +#else
> + = pde->proc_fops->get_unmapped_area;
> #endif
> - if (pde->proc_fops->get_unmapped_area)
> - get_area = pde->proc_fops->get_unmapped_area;
> - if (get_area)
> - rv = get_area(file, orig_addr, len, pgoff, flags);
> +
> + rv = get_area
> + ? get_area(file, orig_addr, len, pgoff, flags)
> + : orig_addr;
> unuse_pde(pde);
> }
> return rv;
That function has gone from bad to worse :(
How does this version look?
It would be acceptable and beneficial to create a new get_unmapped_area_t.
: static unsigned long
: proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
: unsigned long len, unsigned long pgoff,
: unsigned long flags)
: {
: struct proc_dir_entry *pde = PDE(file_inode(file));
: unsigned long rv = -EIO;
:
: if (use_pde(pde)) {
: typeof(proc_reg_get_unmapped_area) *get_area;
:
: get_area = pde->proc_fops->get_unmapped_area;
: #ifdef CONFIG_MMU
: if (!get_area)
: get_area = current->mm->get_unmapped_area;
: #endif
:
: if (get_area)
: rv = get_area(file, orig_addr, len, pgoff, flags);
: else
: rv = orig_addr;
: unuse_pde(pde);
: }
: return rv;
: }
---
a/fs/proc/inode.c~procfs-also-fix-proc_reg_get_unmapped_area-for-mmu-case-fix
+++ a/fs/proc/inode.c
@@ -294,17 +294,18 @@ proc_reg_get_unmapped_area(struct file *
unsigned long rv = -EIO;
if (use_pde(pde)) {
- typeof(proc_reg_get_unmapped_area) *get_area
+ typeof(proc_reg_get_unmapped_area) *get_area;
+
+ get_area = pde->proc_fops->get_unmapped_area;
#ifdef CONFIG_MMU
- = pde->proc_fops->get_unmapped_area
- ?: current->mm->get_unmapped_area;
-#else
- = pde->proc_fops->get_unmapped_area;
+ if (!get_area)
+ get_area = current->mm->get_unmapped_area;
#endif
- rv = get_area
- ? get_area(file, orig_addr, len, pgoff, flags)
- : orig_addr;
+ if (get_area)
+ rv = get_area(file, orig_addr, len, pgoff, flags);
+ else
+ rv = orig_addr;
unuse_pde(pde);
}
return rv;
_
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