From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id B30476B0069 for ; Thu, 24 Nov 2016 04:47:02 -0500 (EST) Received: by mail-wm0-f71.google.com with SMTP id u144so13209590wmu.1 for ; Thu, 24 Nov 2016 01:47:02 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id ip3si35950429wjb.97.2016.11.24.01.47.01 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 24 Nov 2016 01:47:01 -0800 (PST) From: Jan Kara Subject: [PATCH 4/6] dax: Finish fault completely when loading holes Date: Thu, 24 Nov 2016 10:46:34 +0100 Message-Id: <1479980796-26161-5-git-send-email-jack@suse.cz> In-Reply-To: <1479980796-26161-1-git-send-email-jack@suse.cz> References: <1479980796-26161-1-git-send-email-jack@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: linux-fsdevel@vger.kernel.org Cc: Ross Zwisler , linux-ext4@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, Johannes Weiner , Jan Kara The only case when we do not finish the page fault completely is when we are loading hole pages into a radix tree. Avoid this special case and finish the fault in that case as well inside the DAX fault handler. It will allow us for easier iomap handling. Signed-off-by: Jan Kara --- fs/dax.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index ddf77ef2ca18..38f996976ebf 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -540,15 +540,16 @@ int dax_invalidate_clean_mapping_entry(struct address_space *mapping, * otherwise it will simply fall out of the page cache under memory * pressure without ever having been dirtied. */ -static int dax_load_hole(struct address_space *mapping, void *entry, +static int dax_load_hole(struct address_space *mapping, void **entry, struct vm_fault *vmf) { struct page *page; + int ret; /* Hole page already exists? Return it... */ - if (!radix_tree_exceptional_entry(entry)) { - vmf->page = entry; - return VM_FAULT_LOCKED; + if (!radix_tree_exceptional_entry(*entry)) { + page = *entry; + goto out; } /* This will replace locked radix tree entry with a hole page */ @@ -556,8 +557,17 @@ static int dax_load_hole(struct address_space *mapping, void *entry, vmf->gfp_mask | __GFP_ZERO); if (!page) return VM_FAULT_OOM; + out: vmf->page = page; - return VM_FAULT_LOCKED; + ret = finish_fault(vmf); + vmf->page = NULL; + *entry = page; + if (!ret) { + /* Grab reference for PTE that is now referencing the page */ + get_page(page); + return VM_FAULT_NOPAGE; + } + return ret; } static int copy_user_dax(struct block_device *bdev, sector_t sector, size_t size, @@ -1162,8 +1172,8 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, case IOMAP_UNWRITTEN: case IOMAP_HOLE: if (!(vmf->flags & FAULT_FLAG_WRITE)) { - vmf_ret = dax_load_hole(mapping, entry, vmf); - break; + vmf_ret = dax_load_hole(mapping, &entry, vmf); + goto finish_iomap; } /*FALLTHRU*/ default: @@ -1184,8 +1194,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } } unlock_entry: - if (vmf_ret != VM_FAULT_LOCKED || error) - put_locked_mapping_entry(mapping, vmf->pgoff, entry); + put_locked_mapping_entry(mapping, vmf->pgoff, entry); out: if (error == -ENOMEM) return VM_FAULT_OOM | major; -- 2.6.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org