From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by kanga.kvack.org (Postfix) with ESMTP id 686FA6B0035 for ; Wed, 30 Jul 2014 16:34:39 -0400 (EDT) Received: by mail-pa0-f53.google.com with SMTP id rd3so2160273pab.26 for ; Wed, 30 Jul 2014 13:34:39 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTP id gy11si3521708pbd.84.2014.07.30.13.34.37 for ; Wed, 30 Jul 2014 13:34:38 -0700 (PDT) Date: Wed, 30 Jul 2014 16:34:35 -0400 From: Matthew Wilcox Subject: Re: [PATCH v8 04/22] Change direct_access calling convention Message-ID: <20140730203435.GR6754@linux.intel.com> References: <53D9174C.7040906@gmail.com> <53D9197C.2050000@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53D9197C.2050000@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Boaz Harrosh Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, Jul 30, 2014 at 07:12:44PM +0300, Boaz Harrosh wrote: > Off course I was wrong here size is in bytes not in sectors. Which points > out that maybe this API needs to be in sectors. > > [Actually it needs to be in pages both size and offset, because of return of > pfn, but its your call.] I considered a number of options here. The VM wants things to be in pages. The filesystem wants things to be in block size. The block device wants things to be in sectors. It's all a mess when you try and converge. Everybody understands bytes. Here's what I've come up with on top of patch 4/22. Let me know what you think. diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c index 3ee1c08..741293f 100644 --- a/arch/powerpc/sysdev/axonram.c +++ b/arch/powerpc/sysdev/axonram.c @@ -146,11 +146,6 @@ axon_ram_direct_access(struct block_device *device, sector_t sector, struct axon_ram_bank *bank = device->bd_disk->private_data; loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT; - if (offset >= bank->size) { - dev_err(&bank->device->dev, "Access outside of address space\n"); - return -ERANGE; - } - *kaddr = (void *)(bank->ph_addr + offset); *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT; diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 33a39e7..3483458 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -378,10 +378,6 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector, if (!brd) return -ENODEV; - if (sector & (PAGE_SECTORS-1)) - return -EINVAL; - if (sector + PAGE_SECTORS > get_capacity(bdev->bd_disk)) - return -ERANGE; page = brd_insert_page(brd, sector); if (!page) return -ENOSPC; diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index 58958d1..2ee5556 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -877,11 +877,7 @@ dcssblk_direct_access (struct block_device *bdev, sector_t secnum, if (!dev_info) return -ENODEV; dev_sz = dev_info->end - dev_info->start; - if (secnum % (PAGE_SIZE/512)) - return -EINVAL; offset = secnum * 512; - if (offset > dev_sz) - return -ERANGE; *kaddr = (void *) (dev_info->start + offset); *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT; diff --git a/fs/block_dev.c b/fs/block_dev.c index f1a158e..93ebdd53 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -450,8 +450,14 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector, const struct block_device_operations *ops = bdev->bd_disk->fops; if (!ops->direct_access) return -EOPNOTSUPP; - return ops->direct_access(bdev, sector + get_start_sect(bdev), addr, - pfn, size); + if ((sector + DIV_ROUND_UP(size, 512)) > + part_nr_sects_read(bdev->bd_part)) + return -ERANGE; + sector += get_start_sect(bdev); + if (sector % (PAGE_SIZE / 512)) + return -EINVAL; + size = ops->direct_access(bdev, sector, addr, pfn, size); + return size ? size : -ERANGE; } EXPORT_SYMBOL_GPL(bdev_direct_access); -- 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