On Tue, May 05, 2020 at 01:39:16PM -0500, Eric W. Biederman wrote: > Hari Bathini <hbathini@xxxxxxxxxxxxx> writes: > > > On 05/05/20 3:29 am, Eric W. Biederman wrote: > >> > >> Recently a patch was proposed to kimage_alloc_page to slightly alter > >> the logic of how pages allocated with incompatible flags were > >> detected. The logic was being altered because the semantics of the > >> page alloctor were changing yet again. > >> > >> Looking at that case I realized that there is no reason for it to even > >> exist. Either the indirect page allocations and the source page > >> allocations could be separated out, or I could do as I am doing now > >> and simply teach the indirect pages to live in high memory. > >> > >> This patch replaced pointers of type kimage_entry_t * with a new type > >> kimage_entry_pos_t. This new type holds the physical address of the > >> indirect page and the offset within that page of the next indirect > >> entry to write. A special constant KIMAGE_ENTRY_POS_INVALID is added > >> that kimage_image_pos_t variables that don't currently have a valid > >> may be set to. > >> > >> Two new functions kimage_read_entry and kimage_write_entry have been > >> provided to write entries in way that works if they live in high > >> memory. > >> > >> The now unnecessary checks to see if a destination entry is non-zero > >> and to increment it if so have been removed. For safety new indrect > >> pages are now cleared so we have a guarantee everything that has not > >> been used yet is zero. Along with this writing an extra trailing 0 > >> entry has been removed, as it is known all trailing entries are now 0. > >> > >> With highmem support implemented for indirect pages > >> kimage_image_alloc_page has been updated to always allocate > >> GFP_HIGHUSER pages, and handling of pages with different > >> gfp flags has been removed. > >> > >> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > > > Eric, the patch failed with data access exception on ppc64. Using the below patch on top > > got me going... > > Doh! Somehow I thought I had put that logic or something equivalent > into kimage_write_entry and it appears I did not. I will see if I can > respin the patch. > > Thank you very much for testing. Hello, Eric. It seems that this patch isn't upstreamed. Could you respin the patch? I've tested this one on x86_32 (highmem enabled) and it works well. Thanks.
