From patchwork Thu Apr 16 05:31:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11492289 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7A98E913 for ; Thu, 16 Apr 2020 05:32:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2CC0120771 for ; Thu, 16 Apr 2020 05:32:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="o5C4y+Ts" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CC0120771 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 447698E007F; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 3D5848E007E; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 274598E007F; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0101.hostedemail.com [216.40.44.101]) by kanga.kvack.org (Postfix) with ESMTP id 0E3028E0001 for ; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B96D4585D for ; Thu, 16 Apr 2020 05:32:14 +0000 (UTC) X-FDA: 76712597388.20.toys65_138879535cd59 X-Spam-Summary: 2,0,0,3f8b8740b668c865,d41d8cd98f00b204,batv+5bc73a3a1daf6c448284+6080+infradead.org+hch@bombadil.srs.infradead.org,,RULES_HIT:4:41:69:355:379:541:800:960:973:988:989:1042:1260:1311:1314:1345:1359:1431:1434:1437:1515:1605:1730:1747:1777:1792:1801:2393:2538:2559:2562:2639:2693:3138:3139:3140:3141:3142:3865:3866:3867:3868:3870:3871:3872:3874:4250:4321:4605:5007:6119:6261:6653:6742:7809:7875:7903:9010:9149:9592:10004:11026:11473:11657:11658:11914:12043:12160:12296:12297:12438:12517:12519:12555:12895:12986:13161:13229:13894:14096:14394:21080:21433:21451:21627:21740:21772:21987:30045:30054:30055:30064:30067,0,RBL:198.137.202.133:@bombadil.srs.infradead.org:.lbl8.mailshell.net-64.201.201.201 62.8.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: toys65_138879535cd59 X-Filterd-Recvd-Size: 15647 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf16.hostedemail.com (Postfix) with ESMTP for ; Thu, 16 Apr 2020 05:32:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=SVuBq79e0qB3sbkQmjsapq4IOy80jQar5oImUUqnrfY=; b=o5C4y+TsU+kJsUjTGzv+tVAbLl hiHyIHr6UKLkP+q9P0Mj1bwczyn+mL1PGAgcwWjLFxGT5/xkoa4z7ByX+vQaCPq43vjqfQ39ACVrx 1M1DVR2LpU8c90uyYXo1U+BnrcoG71M1nmOZskpptb4z6LvI1PU28YhJwyARgbuDKG3TOPT+Y0/Jo 0aJTMMo4Z3cK2p4ovRkeCeSAWjHvVT+AOg9uZNGJFtzUP/UGHvmP8d8YutoguAFFNqII3flozQfj6 x831PTSrPB9iDFqMbeTH9p/L9n8aIAZFbLvrloMyX5pBeimP0gdNPRooufBgSbpUBFxR0vaLLcwgm xLRGP4Mg==; Received: from [2001:4bb8:184:4aa1:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOx87-0003d5-6i; Thu, 16 Apr 2020 05:32:03 +0000 From: Christoph Hellwig To: Linus Torvalds , Andrew Morton Cc: Al Viro , Felix Kuehling , Alex Deucher , Zhenyu Wang , Zhi Wang , Felipe Balbi , "Michael S. Tsirkin" , Jason Wang , Jens Axboe , linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-usb@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 1/3] kernel: move use_mm/unuse_mm to kthread.c Date: Thu, 16 Apr 2020 07:31:56 +0200 Message-Id: <20200416053158.586887-2-hch@lst.de> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200416053158.586887-1-hch@lst.de> References: <20200416053158.586887-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: These helpers are only for use with kernel threads, and I will tie them more into the kthread infrastructure going forward. Also move the prototypes to kthread.h - mmu_context.h was a little weird to start with as it otherwise contains very low-level MM bits. Signed-off-by: Christoph Hellwig Acked-by: Felix Kuehling --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 1 + .../drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c | 1 - .../drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c | 1 - .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c | 2 - .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c | 2 - .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c | 2 - drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +- drivers/usb/gadget/function/f_fs.c | 2 +- drivers/usb/gadget/legacy/inode.c | 2 +- drivers/vfio/vfio_iommu_type1.c | 2 +- drivers/vhost/vhost.c | 1 - fs/aio.c | 1 - fs/io-wq.c | 1 - fs/io_uring.c | 1 - include/linux/kthread.h | 5 ++ include/linux/mmu_context.h | 5 -- kernel/kthread.c | 56 ++++++++++++++++ mm/Makefile | 2 +- mm/mmu_context.c | 64 ------------------- 19 files changed, 67 insertions(+), 86 deletions(-) delete mode 100644 mm/mmu_context.c diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h index 13feb313e9b3..b820c8fc689f 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h @@ -27,6 +27,7 @@ #include #include +#include #include #include #include diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c index 6529caca88fe..35d4a5ab0228 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c @@ -22,7 +22,6 @@ #include #include #include -#include #include #include "amdgpu.h" #include "amdgpu_amdkfd.h" diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c index 4ec6d0c03201..b1655054b919 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c @@ -19,7 +19,6 @@ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ -#include #include "amdgpu.h" #include "amdgpu_amdkfd.h" #include "gc/gc_10_1_0_offset.h" diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c index 0b7e78748540..7d01420c0c85 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c @@ -20,8 +20,6 @@ * OTHER DEALINGS IN THE SOFTWARE. */ -#include - #include "amdgpu.h" #include "amdgpu_amdkfd.h" #include "cikd.h" diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c index ccd635b812b5..635cd1a26bed 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c @@ -20,8 +20,6 @@ * OTHER DEALINGS IN THE SOFTWARE. */ -#include - #include "amdgpu.h" #include "amdgpu_amdkfd.h" #include "gfx_v8_0.h" diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c index df841c2ac5e7..c7fd0c47b254 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c @@ -19,8 +19,6 @@ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ -#include - #include "amdgpu.h" #include "amdgpu_amdkfd.h" #include "gc/gc_9_0_offset.h" diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 074c4efb58eb..ca1dd6e6f395 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -31,7 +31,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index c81023b195c3..c57b1b2507c6 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -32,7 +32,7 @@ #include #include -#include +#include #include #include diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index aa0de9e35afa..8b5233888bf8 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -21,7 +21,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 85b32c325282..5f50866a8b01 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -27,7 +27,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index d450e16c5c25..ead1deed80d3 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -14,7 +14,6 @@ #include #include #include -#include #include #include #include diff --git a/fs/aio.c b/fs/aio.c index 5f3d3d814928..328829f0343b 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -27,7 +27,6 @@ #include #include #include -#include #include #include #include diff --git a/fs/io-wq.c b/fs/io-wq.c index 4023c9846860..5f590bf27bff 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -10,7 +10,6 @@ #include #include #include -#include #include #include #include diff --git a/fs/io_uring.c b/fs/io_uring.c index 5190bfb6a665..f5a80f6f28f5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -55,7 +55,6 @@ #include #include #include -#include #include #include #include diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 8bbcaad7ef0f..c2d40c9672d6 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -5,6 +5,8 @@ #include #include +struct mm_struct; + __printf(4, 5) struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), void *data, @@ -198,6 +200,9 @@ bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work); void kthread_destroy_worker(struct kthread_worker *worker); +void use_mm(struct mm_struct *mm); +void unuse_mm(struct mm_struct *mm); + struct cgroup_subsys_state; #ifdef CONFIG_BLK_CGROUP diff --git a/include/linux/mmu_context.h b/include/linux/mmu_context.h index d9a543a9e1cc..c51a84132d7c 100644 --- a/include/linux/mmu_context.h +++ b/include/linux/mmu_context.h @@ -4,11 +4,6 @@ #include -struct mm_struct; - -void use_mm(struct mm_struct *mm); -void unuse_mm(struct mm_struct *mm); - /* Architectures that care about IRQ state in switch_mm can override this. */ #ifndef switch_mm_irqs_off # define switch_mm_irqs_off switch_mm diff --git a/kernel/kthread.c b/kernel/kthread.c index bfbfa481be3a..ce4610316377 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1,13 +1,17 @@ // SPDX-License-Identifier: GPL-2.0-only /* Kernel thread helper functions. * Copyright (C) 2004 IBM Corporation, Rusty Russell. + * Copyright (C) 2009 Red Hat, Inc. * * Creation is done via kthreadd, so that we get a clean environment * even if we're invoked from userspace (think modprobe, hotplug cpu, * etc.). */ #include +#include +#include #include +#include #include #include #include @@ -25,6 +29,7 @@ #include #include + static DEFINE_SPINLOCK(kthread_create_lock); static LIST_HEAD(kthread_create_list); struct task_struct *kthreadd_task; @@ -1203,6 +1208,57 @@ void kthread_destroy_worker(struct kthread_worker *worker) } EXPORT_SYMBOL(kthread_destroy_worker); +/* + * use_mm + * Makes the calling kernel thread take on the specified + * mm context. + * (Note: this routine is intended to be called only + * from a kernel thread context) + */ +void use_mm(struct mm_struct *mm) +{ + struct mm_struct *active_mm; + struct task_struct *tsk = current; + + task_lock(tsk); + active_mm = tsk->active_mm; + if (active_mm != mm) { + mmgrab(mm); + tsk->active_mm = mm; + } + tsk->mm = mm; + switch_mm(active_mm, mm, tsk); + task_unlock(tsk); +#ifdef finish_arch_post_lock_switch + finish_arch_post_lock_switch(); +#endif + + if (active_mm != mm) + mmdrop(active_mm); +} +EXPORT_SYMBOL_GPL(use_mm); + +/* + * unuse_mm + * Reverses the effect of use_mm, i.e. releases the + * specified mm context which was earlier taken on + * by the calling kernel thread + * (Note: this routine is intended to be called only + * from a kernel thread context) + */ +void unuse_mm(struct mm_struct *mm) +{ + struct task_struct *tsk = current; + + task_lock(tsk); + sync_mm_rss(mm); + tsk->mm = NULL; + /* active_mm is still 'mm' */ + enter_lazy_tlb(mm, tsk); + task_unlock(tsk); +} +EXPORT_SYMBOL_GPL(unuse_mm); + #ifdef CONFIG_BLK_CGROUP /** * kthread_associate_blkcg - associate blkcg to current kthread diff --git a/mm/Makefile b/mm/Makefile index fccd3756b25f..cafde277ed8d 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -41,7 +41,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ maccess.o page-writeback.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ util.o mmzone.o vmstat.o backing-dev.o \ - mm_init.o mmu_context.o percpu.o slab_common.o \ + mm_init.o percpu.o slab_common.o \ compaction.o vmacache.o \ interval_tree.o list_lru.o workingset.o \ debug.o gup.o $(mmu-y) diff --git a/mm/mmu_context.c b/mm/mmu_context.c deleted file mode 100644 index 3e612ae748e9..000000000000 --- a/mm/mmu_context.c +++ /dev/null @@ -1,64 +0,0 @@ -/* Copyright (C) 2009 Red Hat, Inc. - * - * See ../COPYING for licensing terms. - */ - -#include -#include -#include -#include -#include -#include - -#include - -/* - * use_mm - * Makes the calling kernel thread take on the specified - * mm context. - * (Note: this routine is intended to be called only - * from a kernel thread context) - */ -void use_mm(struct mm_struct *mm) -{ - struct mm_struct *active_mm; - struct task_struct *tsk = current; - - task_lock(tsk); - active_mm = tsk->active_mm; - if (active_mm != mm) { - mmgrab(mm); - tsk->active_mm = mm; - } - tsk->mm = mm; - switch_mm(active_mm, mm, tsk); - task_unlock(tsk); -#ifdef finish_arch_post_lock_switch - finish_arch_post_lock_switch(); -#endif - - if (active_mm != mm) - mmdrop(active_mm); -} -EXPORT_SYMBOL_GPL(use_mm); - -/* - * unuse_mm - * Reverses the effect of use_mm, i.e. releases the - * specified mm context which was earlier taken on - * by the calling kernel thread - * (Note: this routine is intended to be called only - * from a kernel thread context) - */ -void unuse_mm(struct mm_struct *mm) -{ - struct task_struct *tsk = current; - - task_lock(tsk); - sync_mm_rss(mm); - tsk->mm = NULL; - /* active_mm is still 'mm' */ - enter_lazy_tlb(mm, tsk); - task_unlock(tsk); -} -EXPORT_SYMBOL_GPL(unuse_mm); From patchwork Thu Apr 16 05:31:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11492295 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F0C02913 for ; Thu, 16 Apr 2020 05:32:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A479020771 for ; Thu, 16 Apr 2020 05:32:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="NW+cnTIK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A479020771 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 69F3B8E007E; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 4E5E88E0080; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 310C38E0001; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0180.hostedemail.com [216.40.44.180]) by kanga.kvack.org (Postfix) with ESMTP id 109168E007E for ; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id BED9C5DFD for ; Thu, 16 Apr 2020 05:32:14 +0000 (UTC) X-FDA: 76712597388.11.shake36_1383adb82075c X-Spam-Summary: 2,0,0,b3b1758116e7def6,d41d8cd98f00b204,batv+5bc73a3a1daf6c448284+6080+infradead.org+hch@bombadil.srs.infradead.org,,RULES_HIT:1:41:69:355:379:541:800:960:973:988:989:1260:1311:1314:1345:1359:1437:1515:1605:1730:1747:1777:1792:1801:2393:2553:2559:2562:2636:2898:3138:3139:3140:3141:3142:3865:3866:3867:3868:3870:3871:3872:3874:4321:4605:5007:6119:6261:6653:6691:6742:7875:7903:7904:8531:10004:11026:11473:11657:11658:11914:12043:12160:12294:12296:12297:12438:12517:12519:12555:12679:12895:12986:13894:14096:14394:14877:21080:21220:21433:21451:21627:21740:21795:21987:21990:30003:30051:30054:30055:30064:30070:30090,0,RBL:198.137.202.133:@bombadil.srs.infradead.org:.lbl8.mailshell.net-64.201.201.201 62.8.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:34,LUA_SUMMARY:none X-HE-Tag: shake36_1383adb82075c X-Filterd-Recvd-Size: 12931 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Thu, 16 Apr 2020 05:32:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=hjp14iUZlRKTsu3uiFZgsg/rZSgDThHclQfpO/jd+7A=; b=NW+cnTIKfLE8yZDKQxf0Vg0THe 5H5KzRETI5QOYIlFyPmeCgPjtkaUhqXHeZZZGR/B+w8PXjfEd3lNa9Mj4/QGOn9tRUvEyT/HP9ZIp cKEl09X0/SbpZcRbE1Mh7Vb8zgGIkzoVR64uw8oNvPmVn2QsTvA69pwSJU2Q9bz6jt8JwGUEha4a3 nEyjxcyILK4jFRfqVPEF9h3TFLMWpf06HDpQ10he4+pJSYC72xrIKSlVdJSFZ2mOVmnJ/zSW+Wkkg up4NceVeglq0unxoki79IiA560yjgT195Q5ZMkbfrmRVZHPrxLQzMKmwpSM4G7LUPJzX6NE+e8U3J 03vtijDA==; Received: from [2001:4bb8:184:4aa1:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOx89-0003dI-PY; Thu, 16 Apr 2020 05:32:06 +0000 From: Christoph Hellwig To: Linus Torvalds , Andrew Morton Cc: Al Viro , Felix Kuehling , Alex Deucher , Zhenyu Wang , Zhi Wang , Felipe Balbi , "Michael S. Tsirkin" , Jason Wang , Jens Axboe , linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-usb@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 2/3] kernel: better document the use_mm/unuse_mm API contract Date: Thu, 16 Apr 2020 07:31:57 +0200 Message-Id: <20200416053158.586887-3-hch@lst.de> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200416053158.586887-1-hch@lst.de> References: <20200416053158.586887-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. Signed-off-by: Christoph Hellwig Acked-by: Felix Kuehling Acked-by: Greg Kroah-Hartman [usb] --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 4 +-- drivers/gpu/drm/i915/gvt/kvmgt.c | 4 +-- drivers/usb/gadget/function/f_fs.c | 4 +-- drivers/usb/gadget/legacy/inode.c | 4 +-- drivers/vfio/vfio_iommu_type1.c | 4 +-- drivers/vhost/vhost.c | 4 +-- fs/io-wq.c | 6 ++-- fs/io_uring.c | 6 ++-- include/linux/kthread.h | 4 +-- kernel/kthread.c | 33 +++++++++++----------- mm/oom_kill.c | 6 ++-- mm/vmacache.c | 4 +-- 12 files changed, 41 insertions(+), 42 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h index b820c8fc689f..b063bd7f41d8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h @@ -192,9 +192,9 @@ uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev *s if ((mmptr) == current->mm) { \ valid = !get_user((dst), (wptr)); \ } else if (current->mm == NULL) { \ - use_mm(mmptr); \ + kthread_use_mm(mmptr); \ valid = !get_user((dst), (wptr)); \ - unuse_mm(mmptr); \ + kthread_unuse_mm(mmptr); \ } \ pagefault_enable(); \ } \ diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index ca1dd6e6f395..f2927575b793 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -2048,7 +2048,7 @@ static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa, if (kthread) { if (!mmget_not_zero(kvm->mm)) return -EFAULT; - use_mm(kvm->mm); + kthread_use_mm(kvm->mm); } idx = srcu_read_lock(&kvm->srcu); @@ -2057,7 +2057,7 @@ static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa, srcu_read_unlock(&kvm->srcu, idx); if (kthread) { - unuse_mm(kvm->mm); + kthread_unuse_mm(kvm->mm); mmput(kvm->mm); } diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index c57b1b2507c6..d9e48bd7c692 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -827,9 +827,9 @@ static void ffs_user_copy_worker(struct work_struct *work) mm_segment_t oldfs = get_fs(); set_fs(USER_DS); - use_mm(io_data->mm); + kthread_use_mm(io_data->mm); ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data); - unuse_mm(io_data->mm); + kthread_unuse_mm(io_data->mm); set_fs(oldfs); } diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 8b5233888bf8..a05552bc2ff8 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -462,9 +462,9 @@ static void ep_user_copy_worker(struct work_struct *work) struct kiocb *iocb = priv->iocb; size_t ret; - use_mm(mm); + kthread_use_mm(mm); ret = copy_to_iter(priv->buf, priv->actual, &priv->to); - unuse_mm(mm); + kthread_unuse_mm(mm); if (!ret) ret = -EFAULT; diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 5f50866a8b01..2eb105aa9723 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -2333,7 +2333,7 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, return -EPERM; if (kthread) - use_mm(mm); + kthread_use_mm(mm); else if (current->mm != mm) goto out; @@ -2351,7 +2351,7 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, *copied = __copy_from_user(data, (void __user *)vaddr, count) ? 0 : count; if (kthread) - unuse_mm(mm); + kthread_unuse_mm(mm); out: mmput(mm); return *copied ? 0 : -EFAULT; diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ead1deed80d3..17d598e74780 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -332,7 +332,7 @@ static int vhost_worker(void *data) mm_segment_t oldfs = get_fs(); set_fs(USER_DS); - use_mm(dev->mm); + kthread_use_mm(dev->mm); for (;;) { /* mb paired w/ kthread_stop */ @@ -360,7 +360,7 @@ static int vhost_worker(void *data) schedule(); } } - unuse_mm(dev->mm); + kthread_unuse_mm(dev->mm); set_fs(oldfs); return 0; } diff --git a/fs/io-wq.c b/fs/io-wq.c index 5f590bf27bff..748621f7391e 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -170,7 +170,7 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker) } __set_current_state(TASK_RUNNING); set_fs(KERNEL_DS); - unuse_mm(worker->mm); + kthread_unuse_mm(worker->mm); mmput(worker->mm); worker->mm = NULL; } @@ -417,7 +417,7 @@ static struct io_wq_work *io_get_next_work(struct io_wqe *wqe) static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work) { if (worker->mm) { - unuse_mm(worker->mm); + kthread_unuse_mm(worker->mm); mmput(worker->mm); worker->mm = NULL; } @@ -426,7 +426,7 @@ static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work) return; } if (mmget_not_zero(work->mm)) { - use_mm(work->mm); + kthread_use_mm(work->mm); if (!worker->mm) set_fs(USER_DS); worker->mm = work->mm; diff --git a/fs/io_uring.c b/fs/io_uring.c index f5a80f6f28f5..8a8148512da7 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5876,7 +5876,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr, err = -EFAULT; goto fail_req; } - use_mm(ctx->sqo_mm); + kthread_use_mm(ctx->sqo_mm); *mm = ctx->sqo_mm; } @@ -5948,7 +5948,7 @@ static int io_sq_thread(void *data) * may sleep. */ if (cur_mm) { - unuse_mm(cur_mm); + kthread_unuse_mm(cur_mm); mmput(cur_mm); cur_mm = NULL; } @@ -6025,7 +6025,7 @@ static int io_sq_thread(void *data) set_fs(old_fs); if (cur_mm) { - unuse_mm(cur_mm); + kthread_unuse_mm(cur_mm); mmput(cur_mm); } revert_creds(old_cred); diff --git a/include/linux/kthread.h b/include/linux/kthread.h index c2d40c9672d6..12258ea077cf 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -200,8 +200,8 @@ bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work); void kthread_destroy_worker(struct kthread_worker *worker); -void use_mm(struct mm_struct *mm); -void unuse_mm(struct mm_struct *mm); +void kthread_use_mm(struct mm_struct *mm); +void kthread_unuse_mm(struct mm_struct *mm); struct cgroup_subsys_state; diff --git a/kernel/kthread.c b/kernel/kthread.c index ce4610316377..8ed4b4fbec7c 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1208,18 +1208,18 @@ void kthread_destroy_worker(struct kthread_worker *worker) } EXPORT_SYMBOL(kthread_destroy_worker); -/* - * use_mm - * Makes the calling kernel thread take on the specified - * mm context. - * (Note: this routine is intended to be called only - * from a kernel thread context) +/** + * kthread_use_mm - make the calling kthread operate on an address space + * @mm: address space to operate on */ -void use_mm(struct mm_struct *mm) +void kthread_use_mm(struct mm_struct *mm) { struct mm_struct *active_mm; struct task_struct *tsk = current; + WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); + WARN_ON_ONCE(tsk->mm); + task_lock(tsk); active_mm = tsk->active_mm; if (active_mm != mm) { @@ -1236,20 +1236,19 @@ void use_mm(struct mm_struct *mm) if (active_mm != mm) mmdrop(active_mm); } -EXPORT_SYMBOL_GPL(use_mm); +EXPORT_SYMBOL_GPL(kthread_use_mm); -/* - * unuse_mm - * Reverses the effect of use_mm, i.e. releases the - * specified mm context which was earlier taken on - * by the calling kernel thread - * (Note: this routine is intended to be called only - * from a kernel thread context) +/** + * kthread_unuse_mm - reverse the effect of kthread_use_mm() + * @mm: address space to operate on */ -void unuse_mm(struct mm_struct *mm) +void kthread_unuse_mm(struct mm_struct *mm) { struct task_struct *tsk = current; + WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); + WARN_ON_ONCE(!tsk->mm); + task_lock(tsk); sync_mm_rss(mm); tsk->mm = NULL; @@ -1257,7 +1256,7 @@ void unuse_mm(struct mm_struct *mm) enter_lazy_tlb(mm, tsk); task_unlock(tsk); } -EXPORT_SYMBOL_GPL(unuse_mm); +EXPORT_SYMBOL_GPL(kthread_unuse_mm); #ifdef CONFIG_BLK_CGROUP /** diff --git a/mm/oom_kill.c b/mm/oom_kill.c index dfc357614e56..958d2972313f 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -126,7 +126,7 @@ static bool oom_cpuset_eligible(struct task_struct *tsk, struct oom_control *oc) /* * The process p may have detached its own ->mm while exiting or through - * use_mm(), but one or more of its subthreads may still have a valid + * kthread_use_mm(), but one or more of its subthreads may still have a valid * pointer. Return p, or any of its subthreads with a valid ->mm, with * task_lock() held. */ @@ -919,8 +919,8 @@ static void __oom_kill_process(struct task_struct *victim, const char *message) continue; } /* - * No use_mm() user needs to read from the userspace so we are - * ok to reap it. + * No kthead_use_mm() user needs to read from the userspace so + * we are ok to reap it. */ if (unlikely(p->flags & PF_KTHREAD)) continue; diff --git a/mm/vmacache.c b/mm/vmacache.c index cdc32a3b02fa..ceedbab82106 100644 --- a/mm/vmacache.c +++ b/mm/vmacache.c @@ -25,8 +25,8 @@ * task's vmacache pertains to a different mm (ie, its own). There is * nothing we can do here. * - * Also handle the case where a kernel thread has adopted this mm via use_mm(). - * That kernel thread's vmacache is not applicable to this mm. + * Also handle the case where a kernel thread has adopted this mm via + * kthread_use_mm(). That kernel thread's vmacache is not applicable to this mm. */ static inline bool vmacache_valid_mm(struct mm_struct *mm) { From patchwork Thu Apr 16 05:31:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11492307 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 72637913 for ; Thu, 16 Apr 2020 05:32:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 31E0420857 for ; Thu, 16 Apr 2020 05:32:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YibKIVsw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31E0420857 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9EF858E0080; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 9A10A8E0001; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 88D8D8E0081; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0221.hostedemail.com [216.40.44.221]) by kanga.kvack.org (Postfix) with ESMTP id 659018E0001 for ; Thu, 16 Apr 2020 01:32:15 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 284F18245578 for ; Thu, 16 Apr 2020 05:32:15 +0000 (UTC) X-FDA: 76712597430.23.glove49_1397a2994c63a X-Spam-Summary: 2,0,0,0bf7ab404fb6aafd,d41d8cd98f00b204,batv+5bc73a3a1daf6c448284+6080+infradead.org+hch@bombadil.srs.infradead.org,,RULES_HIT:41:355:379:541:800:960:973:988:989:1260:1311:1314:1345:1359:1437:1515:1535:1544:1711:1730:1747:1777:1792:1801:2393:2559:2562:2901:3138:3139:3140:3141:3142:3355:3865:3866:3867:3868:3870:3871:3874:4117:4321:4605:5007:6119:6261:6653:6742:7903:8531:9592:10004:11026:11473:11657:11658:11914:12043:12160:12296:12297:12438:12517:12519:12555:12895:13894:14096:14181:14394:14721:14877:21080:21324:21451:21627:21740:21795:21972:21990:30003:30051:30054:30069,0,RBL:198.137.202.133:@bombadil.srs.infradead.org:.lbl8.mailshell.net-62.8.0.100 64.201.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:90,LUA_SUMMARY:none X-HE-Tag: glove49_1397a2994c63a X-Filterd-Recvd-Size: 6910 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Thu, 16 Apr 2020 05:32:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=067wQeP/XsQZz7g9kDshfnJ5VToeesdhipVsn0gNrtY=; b=YibKIVswQ5pUBnsRMM6VfjsvQ8 g4PkIfoEwbBcSGD1mLF+cQGk90fOYWm0fTmHuUNjn6GTpQXyIWjV4KoR08kg9crGiaO89xCJvC/0j tyOiapEMb0oHb8sAiYMe6l55EZ2juDaT/0ZiN7o50JEV4RaKsxdjS1w5hhsuNy4H3Ua1KZ+QsQ76i h9udkToejdlmgZPNEn3mYobJY6O79O2dzot1xmq7C1Asm8KAZ9OyZGJMK2joYCbz7VGjYLzEzOGc1 jqkNWWfMFa/3SegvAOVFQRy65e82bVNzbrubo/KsI2n28M9QW1nzS6EMiyZ0NApYCYFDbesPY5sci iWGGTEsg==; Received: from [2001:4bb8:184:4aa1:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOx8C-0003dn-CA; Thu, 16 Apr 2020 05:32:08 +0000 From: Christoph Hellwig To: Linus Torvalds , Andrew Morton Cc: Al Viro , Felix Kuehling , Alex Deucher , Zhenyu Wang , Zhi Wang , Felipe Balbi , "Michael S. Tsirkin" , Jason Wang , Jens Axboe , linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-usb@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 3/3] kernel: set USER_DS in kthread_use_mm Date: Thu, 16 Apr 2020 07:31:58 +0200 Message-Id: <20200416053158.586887-4-hch@lst.de> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200416053158.586887-1-hch@lst.de> References: <20200416053158.586887-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Some architectures like arm64 and s390 require USER_DS to be set for kernel threads to access user address space, which is the whole purpose of kthread_use_mm, but other like x86 don't. That has lead to a huge mess where some callers are fixed up once they are tested on said architectures, while others linger around and yet other like io_uring try to do "clever" optimizations for what usually is just a trivial asignment to a member in the thread_struct for most architectures. Make kthread_use_mm set USER_DS, and kthread_unuse_mm restore to the previous value instead. Signed-off-by: Christoph Hellwig Acked-by: Michael S. Tsirkin [vhost] Acked-by: Greg Kroah-Hartman [usb] --- drivers/usb/gadget/function/f_fs.c | 4 ---- drivers/vhost/vhost.c | 3 --- fs/io-wq.c | 8 ++------ fs/io_uring.c | 4 ---- kernel/kthread.c | 6 ++++++ 5 files changed, 8 insertions(+), 17 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index d9e48bd7c692..a1198f4c527c 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -824,13 +824,9 @@ static void ffs_user_copy_worker(struct work_struct *work) bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD; if (io_data->read && ret > 0) { - mm_segment_t oldfs = get_fs(); - - set_fs(USER_DS); kthread_use_mm(io_data->mm); ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data); kthread_unuse_mm(io_data->mm); - set_fs(oldfs); } io_data->kiocb->ki_complete(io_data->kiocb, ret, ret); diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 17d598e74780..b2abfbdf3cb2 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -329,9 +329,7 @@ static int vhost_worker(void *data) struct vhost_dev *dev = data; struct vhost_work *work, *work_next; struct llist_node *node; - mm_segment_t oldfs = get_fs(); - set_fs(USER_DS); kthread_use_mm(dev->mm); for (;;) { @@ -361,7 +359,6 @@ static int vhost_worker(void *data) } } kthread_unuse_mm(dev->mm); - set_fs(oldfs); return 0; } diff --git a/fs/io-wq.c b/fs/io-wq.c index 748621f7391e..a5e90ac39e4d 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -169,7 +169,6 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker) dropped_lock = true; } __set_current_state(TASK_RUNNING); - set_fs(KERNEL_DS); kthread_unuse_mm(worker->mm); mmput(worker->mm); worker->mm = NULL; @@ -421,14 +420,11 @@ static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work) mmput(worker->mm); worker->mm = NULL; } - if (!work->mm) { - set_fs(KERNEL_DS); + if (!work->mm) return; - } + if (mmget_not_zero(work->mm)) { kthread_use_mm(work->mm); - if (!worker->mm) - set_fs(USER_DS); worker->mm = work->mm; /* hang on to this mm */ work->mm = NULL; diff --git a/fs/io_uring.c b/fs/io_uring.c index 8a8148512da7..40f90b98a18a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5908,15 +5908,12 @@ static int io_sq_thread(void *data) struct io_ring_ctx *ctx = data; struct mm_struct *cur_mm = NULL; const struct cred *old_cred; - mm_segment_t old_fs; DEFINE_WAIT(wait); unsigned long timeout; int ret = 0; complete(&ctx->completions[1]); - old_fs = get_fs(); - set_fs(USER_DS); old_cred = override_creds(ctx->creds); timeout = jiffies + ctx->sq_thread_idle; @@ -6023,7 +6020,6 @@ static int io_sq_thread(void *data) if (current->task_works) task_work_run(); - set_fs(old_fs); if (cur_mm) { kthread_unuse_mm(cur_mm); mmput(cur_mm); diff --git a/kernel/kthread.c b/kernel/kthread.c index 8ed4b4fbec7c..86357cd38eb2 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -52,6 +52,7 @@ struct kthread { unsigned long flags; unsigned int cpu; void *data; + mm_segment_t oldfs; struct completion parked; struct completion exited; #ifdef CONFIG_BLK_CGROUP @@ -1235,6 +1236,9 @@ void kthread_use_mm(struct mm_struct *mm) if (active_mm != mm) mmdrop(active_mm); + + to_kthread(tsk)->oldfs = get_fs(); + set_fs(USER_DS); } EXPORT_SYMBOL_GPL(kthread_use_mm); @@ -1249,6 +1253,8 @@ void kthread_unuse_mm(struct mm_struct *mm) WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); WARN_ON_ONCE(!tsk->mm); + set_fs(to_kthread(tsk)->oldfs); + task_lock(tsk); sync_mm_rss(mm); tsk->mm = NULL;