From: Jan Kara Subject: [PATCH 06/18] dax: Remove dead zeroing code from fault handlers Date: Mon, 18 Apr 2016 23:35:29 +0200 Message-ID: <1461015341-20153-7-git-send-email-jack@suse.cz> References: <1461015341-20153-1-git-send-email-jack@suse.cz> Cc: linux-ext4@vger.kernel.org, linux-mm@kvack.org, Ross Zwisler , Dan Williams , linux-nvdimm@lists.01.org, Matthew Wilcox , Jan Kara To: linux-fsdevel@vger.kernel.org Return-path: In-Reply-To: <1461015341-20153-1-git-send-email-jack@suse.cz> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org Now that all filesystems zero out blocks allocated for a fault handler, we can just remove the zeroing from the handler itself. Also add checks that no filesystem returns to us unwritten or new buffer. Signed-off-by: Jan Kara --- fs/dax.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index c5ccf745d279..ccb8bc399d78 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -587,11 +587,6 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh, error = PTR_ERR(dax.addr); goto out; } - - if (buffer_unwritten(bh) || buffer_new(bh)) { - clear_pmem(dax.addr, PAGE_SIZE); - wmb_pmem(); - } dax_unmap_atomic(bdev, &dax); error = dax_radix_entry(mapping, vmf->pgoff, dax.sector, false, @@ -670,7 +665,7 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, if (error) goto unlock_page; - if (!buffer_mapped(&bh) && !buffer_unwritten(&bh) && !vmf->cow_page) { + if (!buffer_mapped(&bh) && !vmf->cow_page) { if (vmf->flags & FAULT_FLAG_WRITE) { error = get_block(inode, block, &bh, 1); count_vm_event(PGMAJFAULT); @@ -722,7 +717,7 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } /* Filesystem should not return unwritten buffers to us! */ - WARN_ON_ONCE(buffer_unwritten(&bh)); + WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); error = dax_insert_mapping(inode, &bh, vma, vmf); out: @@ -854,7 +849,7 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if (get_block(inode, block, &bh, 1) != 0) return VM_FAULT_SIGBUS; alloc = true; - WARN_ON_ONCE(buffer_unwritten(&bh)); + WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); } bdev = bh.b_bdev; @@ -953,14 +948,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, dax_pmd_dbg(&bh, address, "pfn not in memmap"); goto fallback; } - - if (buffer_unwritten(&bh) || buffer_new(&bh)) { - clear_pmem(dax.addr, PMD_SIZE); - wmb_pmem(); - count_vm_event(PGMAJFAULT); - mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); - result |= VM_FAULT_MAJOR; - } dax_unmap_atomic(bdev, &dax); /* -- 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