From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756063AbeDQQQB (ORCPT ); Tue, 17 Apr 2018 12:16:01 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:47168 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755445AbeDQQQA (ORCPT ); Tue, 17 Apr 2018 12:16:00 -0400 Date: Tue, 17 Apr 2018 09:15:57 -0700 From: Matthew Wilcox To: Souptick Joarder Cc: Jani Nikula , joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, airlied@linux.ie, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gpu: drm: i915: Change return type to vm_fault_t Message-ID: <20180417161557.GA3603@bombadil.infradead.org> References: <20180417151127.GA31655@jordon-HP-15-Notebook-PC> <87h8o9g8be.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 17, 2018 at 09:14:32PM +0530, Souptick Joarder wrote: > Not exactly. The plan for these patches is to introduce new vm_fault_t type > in vm_operations_struct fault handlers. It's now available in 4.17-rc1. We will > push all the required drivers/filesystem changes through different maintainers > to linus tree. Once everything is converted into vm_fault_t type then Changing > it from a signed to an unsigned int causes GCC to warn about an assignment > from an incompatible type -- int foo(void) is incompatible with > unsigned int foo(void). > > Please refer 1c8f422059ae ("mm: change return type to vm_fault_t") in 4.17-rc1. I think this patch would be clearer if you did - int ret; + int err; + vm_fault_t ret; Then it would be clearer to the maintainer that you're splitting apart the VM_FAULT and errno codes. Sorry for not catching this during initial review. > On Tue, Apr 17, 2018 at 8:59 PM, Jani Nikula > wrote: > > On Tue, 17 Apr 2018, Souptick Joarder wrote: > >> Use new return type vm_fault_t for fault handler. For > >> now, this is just documenting that the function returns > >> a VM_FAULT value rather than an errno. Once all instances > >> are converted, vm_fault_t will become a distinct type. > >> > >> Reference id -> 1c8f422059ae ("mm: change return type to > >> vm_fault_t") > >> > >> Signed-off-by: Souptick Joarder > >> --- > >> drivers/gpu/drm/i915/i915_drv.h | 3 ++- > >> drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++------- > >> 2 files changed, 10 insertions(+), 8 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > >> index a42deeb..95b0d50 100644 > >> --- a/drivers/gpu/drm/i915/i915_drv.h > >> +++ b/drivers/gpu/drm/i915/i915_drv.h > >> @@ -51,6 +51,7 @@ > >> #include > >> #include > >> #include > >> +#include > >> > >> #include "i915_params.h" > >> #include "i915_reg.h" > >> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv, > >> unsigned int flags); > >> int __must_check i915_gem_suspend(struct drm_i915_private *dev_priv); > >> void i915_gem_resume(struct drm_i915_private *dev_priv); > >> -int i915_gem_fault(struct vm_fault *vmf); > >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf); > >> int i915_gem_object_wait(struct drm_i915_gem_object *obj, > >> unsigned int flags, > >> long timeout, > >> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > >> index dd89abd..bdac690 100644 > >> --- a/drivers/gpu/drm/i915/i915_gem.c > >> +++ b/drivers/gpu/drm/i915/i915_gem.c > >> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void) > >> * The current feature set supported by i915_gem_fault() and thus GTT mmaps > >> * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version). > >> */ > >> -int i915_gem_fault(struct vm_fault *vmf) > >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf) > >> { > >> #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */ > >> struct vm_area_struct *area = vmf->vma; > >> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf) > >> pgoff_t page_offset; > >> unsigned int flags; > >> int ret; > >> + vm_fault_t retval; > > > > What's the point of changing the name? An unnecessary change. > > > > BR, > > Jani. > > > >> > >> /* We don't use vmf->pgoff since that has the fake offset */ > >> page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT; > >> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf) > >> * and so needs to be reported. > >> */ > >> if (!i915_terminally_wedged(&dev_priv->gpu_error)) { > >> - ret = VM_FAULT_SIGBUS; > >> + retval = VM_FAULT_SIGBUS; > >> break; > >> } > >> case -EAGAIN: > >> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf) > >> * EBUSY is ok: this just means that another thread > >> * already did the job. > >> */ > >> - ret = VM_FAULT_NOPAGE; > >> + retval = VM_FAULT_NOPAGE; > >> break; > >> case -ENOMEM: > >> - ret = VM_FAULT_OOM; > >> + retval = VM_FAULT_OOM; > >> break; > >> case -ENOSPC: > >> case -EFAULT: > >> - ret = VM_FAULT_SIGBUS; > >> + retval = VM_FAULT_SIGBUS; > >> break; > >> default: > >> WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret); > >> - ret = VM_FAULT_SIGBUS; > >> + retval = VM_FAULT_SIGBUS; > >> break; > >> } > >> - return ret; > >> + return retval; > >> } > >> > >> static void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj) > >> -- > >> 1.9.1 > >> > > > > -- > > Jani Nikula, Intel Open Source Technology Center