On Wed, Mar 03, 2021 at 08:59:17AM -0800, Dave Hansen wrote:
> On 3/3/21 7:03 AM, Jarkko Sakkinen wrote:
> > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> > index 52d070fb4c9a..ed99c60024dc 100644
> > --- a/arch/x86/kernel/cpu/sgx/main.c
> > +++ b/arch/x86/kernel/cpu/sgx/main.c
> > @@ -305,7 +305,6 @@ static void sgx_reclaim_pages(void)
> > {
> > struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
> > struct sgx_backing backing[SGX_NR_TO_SCAN];
> > - struct sgx_epc_section *section;
> > struct sgx_encl_page *encl_page;
> > struct sgx_epc_page *epc_page;
> > pgoff_t page_index;
> > @@ -378,11 +377,7 @@ static void sgx_reclaim_pages(void)
> > kref_put(&encl_page->encl->refcount, sgx_encl_release);
> > epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
> >
> > - section = &sgx_epc_sections[epc_page->section];
> > - spin_lock(§ion->lock);
> > - list_add_tail(&epc_page->list, §ion->page_list);
> > - section->free_cnt++;
> > - spin_unlock(§ion->lock);
> > + sgx_free_epc_page(epc_page);
> > }
> > }
>
> In current upstream (3fb6d0e00e), sgx_free_epc_page() calls __eremove().
> This code does not call __eremove(). That seems to be changing
> behavior where none was intended.
EREMOVE does not matter here, as it doesn't in almost all most of the sites
where sgx_free_epc_page() is used in the driver. It does nothing to an
uninitialized pages.
The two patches that I posted originally for Kai's series took EREMOVE out
of sgx_free_epc_page() and put an explicit EREMOVE where it is actually
needed, but for reasons unknown to me, that change is gone.
Replacing the ad-hoc code with sgx_free_epc_page() is absolutely the right
action to take because it follows the pattern how sgx_free_epc_page() is
used in the driver.
For reference:
https://lore.kernel.org/linux-sgx/20210113233541.17669-1-jarkko@xxxxxxxxxx/
> Was this, perhaps, based on top of Kai's series that changes the
> behavior of sgx_free_epc_page()?
I did not refer to that patch series.
/Jarkko
