From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F38EC433DB for ; Thu, 14 Jan 2021 07:18:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 497CD239A1 for ; Thu, 14 Jan 2021 07:18:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726742AbhANHSn (ORCPT ); Thu, 14 Jan 2021 02:18:43 -0500 Received: from mx2.suse.de ([195.135.220.15]:36824 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726121AbhANHSn (ORCPT ); Thu, 14 Jan 2021 02:18:43 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 870A1AB7A; Thu, 14 Jan 2021 07:18:01 +0000 (UTC) Subject: Re: [PATCH v13 39/45] sg: add mmap_sz tracking To: Douglas Gilbert , linux-scsi@vger.kernel.org Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, kashyap.desai@broadcom.com References: <20210113224526.861000-1-dgilbert@interlog.com> <20210113224526.861000-40-dgilbert@interlog.com> From: Hannes Reinecke Message-ID: Date: Thu, 14 Jan 2021 08:18:00 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20210113224526.861000-40-dgilbert@interlog.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 1/13/21 11:45 PM, Douglas Gilbert wrote: > Track mmap_sz from prior mmap(2) call, per sg file descriptor. Also > reset this value whenever munmap(2) is called. Fail SG_FLAG_MMAP_IO > uses if mmap(2) hasn't been called or the memory associated with it > is not large enough for the current request. > > Signed-off-by: Douglas Gilbert > --- > drivers/scsi/sg.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c > index c5533bbaf0d5..d0f25f8f572b 100644 > --- a/drivers/scsi/sg.c > +++ b/drivers/scsi/sg.c > @@ -232,6 +232,7 @@ struct sg_fd { /* holds the state of a file descriptor */ > atomic_t waiting; /* number of requests awaiting receive */ > atomic_t req_cnt; /* number of requests */ > int sgat_elem_sz; /* initialized to scatter_elem_sz */ > + int mmap_sz; /* byte size of previous mmap() call */ > unsigned long ffd_bm[1]; /* see SG_FFD_* defines above */ > pid_t tid; /* thread id when opened */ > u8 next_cmd_len; /* 0: automatic, >0: use on next write() */ > @@ -725,10 +726,14 @@ sg_write(struct file *filp, const char __user *p, size_t count, loff_t *ppos) > static inline int > sg_chk_mmap(struct sg_fd *sfp, int rq_flags, int len) > { > + if (!test_bit(SG_FFD_MMAP_CALLED, sfp->ffd_bm)) > + return -EBADFD; > if (atomic_read(&sfp->submitted) > 0) > return -EBUSY; /* already active requests on fd */ > if (len > sfp->rsv_srp->sgat_h.buflen) > return -ENOMEM; /* MMAP_IO size must fit in reserve */ > + if (unlikely(len > sfp->mmap_sz)) > + return -ENOMEM; /* MMAP_IO size can't exceed mmap() size */ > if (rq_flags & SG_FLAG_DIRECT_IO) > return -EINVAL; /* not both MMAP_IO and DIRECT_IO */ > return 0; > @@ -2262,6 +2267,8 @@ sg_vma_close(struct vm_area_struct *vma) > pr_warn("%s: sfp null\n", __func__); > return; > } > + sfp->mmap_sz = 0; > + clear_bit(SG_FFD_MMAP_CALLED, sfp->ffd_bm); > kref_put(&sfp->f_ref, sg_remove_sfp); /* get in: sg_vma_open() */ > } > > @@ -2383,6 +2390,7 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma) > goto fini; > } > } > + sfp->mmap_sz = req_sz; > vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; > vma->vm_private_data = sfp; > vma->vm_ops = &sg_mmap_vm_ops; > @@ -4048,8 +4056,7 @@ sg_proc_debug_fd(struct sg_fd *fp, char *obp, int len, unsigned long idx) > (int)test_bit(SG_FFD_FORCE_PACKID, fp->ffd_bm), > (int)test_bit(SG_FFD_KEEP_ORPHAN, fp->ffd_bm), > fp->ffd_bm[0]); > - n += scnprintf(obp + n, len - n, " mmap_called=%d\n", > - test_bit(SG_FFD_MMAP_CALLED, fp->ffd_bm)); > + n += scnprintf(obp + n, len - n, " mmap_sz=%d\n", fp->mmap_sz); > n += scnprintf(obp + n, len - n, > " submitted=%d waiting=%d open thr_id=%d\n", > atomic_read(&fp->submitted), > What is the point of having the SG_FFD_MMAP_CALLED bit now? Doesn't the new 'mmap_sz' value carry the same information? Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer