| Message ID | 20190821232902.29476-2-jarkko.sakkinen@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | v22 fixes | expand |
On Thu, Aug 22, 2019 at 02:29:01AM +0300, Jarkko Sakkinen wrote: > The existence of the page is checked first hand for legit race > conditions (either two or more concurrent threads running the #PF > handler or the reclaimer has taken over the page): > > /* Page is already resident in the EPC. */ > if (entry->epc_page) { > if (entry->desc & SGX_ENCL_PAGE_RECLAIMED) > return ERR_PTR(-EBUSY); > > return entry; > } > > After that the existence is a checked as a condition for ELDU. > > This commit removes the redundant check. > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > --- Ha, I remember seeing this a while back and completely forgot about it. Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> > arch/x86/kernel/cpu/sgx/encl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index a20d498e9dcd..d6397f7ef3b8 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -123,7 +123,7 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl, > return ERR_CAST(epc_page); > } > > - epc_page = entry->epc_page ? entry->epc_page : sgx_encl_eldu(entry); > + epc_page = sgx_encl_eldu(entry); > if (IS_ERR(epc_page)) > return ERR_CAST(epc_page); > > -- > 2.20.1 >
On Wed, 2019-08-21 at 17:33 -0700, Sean Christopherson wrote: > On Thu, Aug 22, 2019 at 02:29:01AM +0300, Jarkko Sakkinen wrote: > > The existence of the page is checked first hand for legit race > > conditions (either two or more concurrent threads running the #PF > > handler or the reclaimer has taken over the page): > > > > /* Page is already resident in the EPC. */ > > if (entry->epc_page) { > > if (entry->desc & SGX_ENCL_PAGE_RECLAIMED) > > return ERR_PTR(-EBUSY); > > > > return entry; > > } > > > > After that the existence is a checked as a condition for ELDU. > > > > This commit removes the redundant check. > > > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > --- > > Ha, I remember seeing this a while back and completely forgot about it. > > Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> [I guess for this ack-by would be appropriate as they are not mainline patches] Thanks Sean. These kind of regression are almost unavoidable because of heavy rebasing... /Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index a20d498e9dcd..d6397f7ef3b8 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -123,7 +123,7 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl, return ERR_CAST(epc_page); } - epc_page = entry->epc_page ? entry->epc_page : sgx_encl_eldu(entry); + epc_page = sgx_encl_eldu(entry); if (IS_ERR(epc_page)) return ERR_CAST(epc_page);
The existence of the page is checked first hand for legit race conditions (either two or more concurrent threads running the #PF handler or the reclaimer has taken over the page): /* Page is already resident in the EPC. */ if (entry->epc_page) { if (entry->desc & SGX_ENCL_PAGE_RECLAIMED) return ERR_PTR(-EBUSY); return entry; } After that the existence is a checked as a condition for ELDU. This commit removes the redundant check. Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)