From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 2 Mar 2018 23:54:55 +0100 From: Christoph Hellwig Subject: Re: [PATCH v5 09/12] mm, dax: replace IS_DAX() with IS_DEVDAX() or IS_FSDAX() Message-ID: <20180302225455.GD31240@lst.de> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <151996286235.28483.2635632878864807577.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151996286235.28483.2635632878864807577.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: owner-linux-mm@kvack.org To: Dan Williams Cc: linux-nvdimm@lists.01.org, Matthew Wilcox , Ross Zwisler , stable@vger.kernel.org, Jan Kara , linux-xfs@vger.kernel.org, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Thu, Mar 01, 2018 at 07:54:22PM -0800, Dan Williams wrote: > static inline bool vma_is_dax(struct vm_area_struct *vma) > { > - return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host); > + struct inode *inode; > + > + if (!vma->vm_file) > + return false; > + inode = file_inode(vma->vm_file); > + return IS_FSDAX(inode) || IS_DEVDAX(inode); If you look at the definition of IS_FSDAX and IS_DEVDAX this is going to evaluate into some bullshit code. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 65C2322546B8C for ; Thu, 1 Mar 2018 19:57:19 -0800 (PST) Subject: [PATCH v5 09/12] mm, dax: replace IS_DAX() with IS_DEVDAX() or IS_FSDAX() From: Dan Williams Date: Thu, 01 Mar 2018 19:54:22 -0800 Message-ID: <151996286235.28483.2635632878864807577.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Jan Kara , Matthew Wilcox , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: In preparation for fixing the broken definition of S_DAX in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case, convert all IS_DAX() usages to use explicit tests for the DEVDAX and FSDAX sub-cases of DAX functionality. Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- include/linux/fs.h | 16 +++++++--------- mm/fadvise.c | 3 ++- mm/filemap.c | 4 ++-- mm/huge_memory.c | 4 +++- mm/madvise.c | 3 ++- 5 files changed, 16 insertions(+), 14 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index bd0c46880572..33e859e7d100 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3208,21 +3208,19 @@ static inline bool io_is_direct(struct file *filp) static inline bool vma_is_dax(struct vm_area_struct *vma) { - return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host); + struct inode *inode; + + if (!vma->vm_file) + return false; + inode = file_inode(vma->vm_file); + return IS_FSDAX(inode) || IS_DEVDAX(inode); } static inline bool vma_is_fsdax(struct vm_area_struct *vma) { - struct inode *inode; - if (!vma->vm_file) return false; - if (!vma_is_dax(vma)) - return false; - inode = file_inode(vma->vm_file); - if (S_ISCHR(inode->i_mode)) - return false; /* device-dax */ - return true; + return IS_FSDAX(file_inode(vma->vm_file)); } static inline int iocb_flags(struct file *file) diff --git a/mm/fadvise.c b/mm/fadvise.c index 767887f5f3bf..00d9317636a2 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -55,7 +55,8 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice) bdi = inode_to_bdi(mapping->host); - if (IS_DAX(inode) || (bdi == &noop_backing_dev_info)) { + if (IS_FSDAX(inode) || IS_DEVDAX(inode) + || (bdi == &noop_backing_dev_info)) { switch (advice) { case POSIX_FADV_NORMAL: case POSIX_FADV_RANDOM: diff --git a/mm/filemap.c b/mm/filemap.c index 693f62212a59..4bc4e067ebf2 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2357,7 +2357,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) * DAX files, so don't bother trying. */ if (retval < 0 || !count || iocb->ki_pos >= size || - IS_DAX(inode)) + IS_FSDAX(inode)) goto out; } @@ -3225,7 +3225,7 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) * not succeed (even if it did, DAX does not handle dirty * page-cache pages correctly). */ - if (written < 0 || !iov_iter_count(from) || IS_DAX(inode)) + if (written < 0 || !iov_iter_count(from) || IS_FSDAX(inode)) goto out; status = generic_perform_write(file, from, pos = iocb->ki_pos); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 87ab9b8f56b5..ed238936e29b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -529,10 +529,12 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { loff_t off = (loff_t)pgoff << PAGE_SHIFT; + struct inode *inode; if (addr) goto out; - if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) + inode = filp->f_mapping->host; + if (!IS_FSDAX(inode) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) goto out; addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); diff --git a/mm/madvise.c b/mm/madvise.c index 4d3c922ea1a1..bdb83cf018b1 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -275,6 +275,7 @@ static long madvise_willneed(struct vm_area_struct *vma, unsigned long start, unsigned long end) { struct file *file = vma->vm_file; + struct inode *inode = file_inode(file); *prev = vma; #ifdef CONFIG_SWAP @@ -293,7 +294,7 @@ static long madvise_willneed(struct vm_area_struct *vma, return -EBADF; #endif - if (IS_DAX(file_inode(file))) { + if (IS_FSDAX(inode) || IS_DEVDAX(inode)) { /* no bad return value, but ignore advice */ return 0; } _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id CF33622492727 for ; Fri, 2 Mar 2018 14:47:07 -0800 (PST) Date: Fri, 2 Mar 2018 23:53:16 +0100 From: Christoph Hellwig Subject: Re: [PATCH v5 02/12] dax: introduce IS_DEVDAX() and IS_FSDAX() Message-ID: <20180302225316.GC31240@lst.de> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <151996282448.28483.10415125852182473579.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <151996282448.28483.10415125852182473579.stgit@dwillia2-desk3.amr.corp.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: Theodore Ts'o , Matthew Wilcox , "Darrick J. Wong" , linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Andreas Dilger , Alexander Viro , linux-fsdevel@vger.kernel.org, Jan Kara , hch@lst.de List-ID: > +static inline bool IS_DEVDAX(struct inode *inode) > +{ > + if (!IS_ENABLED(CONFIG_DEV_DAX)) > + return false; > + if ((inode->i_flags & S_DAX) == 0) > + return false; > + if (!S_ISCHR(inode->i_mode)) > + return false; > + return true; > +} > + > +static inline bool IS_FSDAX(struct inode *inode) > +{ > + if (!IS_ENABLED(CONFIG_FS_DAX)) > + return false; > + if ((inode->i_flags & S_DAX) == 0) > + return false; > + if (S_ISCHR(inode->i_mode)) > + return false; > + return true; Encoding the is char device or not thing here is just nasty. I think this is going entirely in the wrong direction. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 2 Mar 2018 11:58:11 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH v6] dax: introduce IS_DEVDAX() and IS_FSDAX() Message-ID: <20180302195811.GA18989@magnolia> References: <152001757529.22146.17936438768625217740.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <152001757529.22146.17936438768625217740.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: owner-linux-mm@kvack.org To: Dan Williams Cc: linux-nvdimm@lists.01.org, Theodore Ts'o , Andreas Dilger , Alexander Viro , linux-xfs@vger.kernel.org, Matthew Wilcox , Ross Zwisler , stable@vger.kernel.org, Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, Mar 02, 2018 at 11:06:36AM -0800, Dan Williams wrote: > The current IS_DAX() helper that checks if a file is in DAX mode serves > two purposes. It is a control flow branch condition for DAX vs > non-DAX paths and it is a mechanism to perform dead code elimination. The > dead code elimination is required in the CONFIG_FS_DAX=n case since > there are symbols in fs/dax.c that will be elided. While the > dead code elimination can be addressed with nop stubs for the fs/dax.c > symbols that does not address the need for a DAX control flow helper > where fs/dax.c symbols are not involved. > > Moreover, the control flow changes, in some cases, need to be cognizant > of whether the DAX file is a typical file or a Device-DAX special file. > Introduce IS_DEVDAX() and IS_FSDAX() to simultaneously address the > file-type control flow and dead-code elimination use cases. IS_DAX() > will be deleted after all sites are converted to use the file-type > specific helper. > > Note, this change is also a pre-requisite for fixing the definition of > the S_DAX inode flag in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case. > The flag needs to be defined, non-zero, if either DAX facility is > enabled. > > Cc: "Theodore Ts'o" > Cc: Andreas Dilger > Cc: Alexander Viro > Cc: "Darrick J. Wong" > Cc: linux-xfs@vger.kernel.org > Cc: Matthew Wilcox > Cc: Ross Zwisler > Cc: > Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") > Reported-by: Jan Kara > Reviewed-by: Jan Kara > Signed-off-by: Dan Williams > --- > Changes since v5: > * add comments to clarify the S_ISCHR() checks (Darrick) Looks ok, Reviewed-by: Darrick J. Wong --D > > include/linux/fs.h | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 79c413985305..751975b8b29b 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1909,6 +1909,30 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags > #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ > (inode)->i_rdev == WHITEOUT_DEV) > > +static inline bool IS_DEVDAX(struct inode *inode) > +{ > + if (!IS_ENABLED(CONFIG_DEV_DAX)) > + return false; > + if ((inode->i_flags & S_DAX) == 0) > + return false; > + /* regular files with S_DAX are filesystem-dax instances */ > + if (!S_ISCHR(inode->i_mode)) > + return false; > + return true; > +} > + > +static inline bool IS_FSDAX(struct inode *inode) > +{ > + if (!IS_ENABLED(CONFIG_FS_DAX)) > + return false; > + if ((inode->i_flags & S_DAX) == 0) > + return false; > + /* character devices with S_DAX are device-dax instances */ > + if (S_ISCHR(inode->i_mode)) > + return false; > + return true; > +} > + > static inline bool HAS_UNMAPPED_ID(struct inode *inode) > { > return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid); > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 553332250EDFF for ; Fri, 2 Mar 2018 11:09:32 -0800 (PST) Subject: [PATCH v6] dax: introduce IS_DEVDAX() and IS_FSDAX() From: Dan Williams Date: Fri, 02 Mar 2018 11:06:36 -0800 Message-ID: <152001757529.22146.17936438768625217740.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: References: MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Theodore Ts'o , Matthew Wilcox , "Darrick J. Wong" , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Andreas Dilger , Alexander Viro , linux-fsdevel@vger.kernel.org, Jan Kara List-ID: The current IS_DAX() helper that checks if a file is in DAX mode serves two purposes. It is a control flow branch condition for DAX vs non-DAX paths and it is a mechanism to perform dead code elimination. The dead code elimination is required in the CONFIG_FS_DAX=n case since there are symbols in fs/dax.c that will be elided. While the dead code elimination can be addressed with nop stubs for the fs/dax.c symbols that does not address the need for a DAX control flow helper where fs/dax.c symbols are not involved. Moreover, the control flow changes, in some cases, need to be cognizant of whether the DAX file is a typical file or a Device-DAX special file. Introduce IS_DEVDAX() and IS_FSDAX() to simultaneously address the file-type control flow and dead-code elimination use cases. IS_DAX() will be deleted after all sites are converted to use the file-type specific helper. Note, this change is also a pre-requisite for fixing the definition of the S_DAX inode flag in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case. The flag needs to be defined, non-zero, if either DAX facility is enabled. Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Alexander Viro Cc: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Jan Kara Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- Changes since v5: * add comments to clarify the S_ISCHR() checks (Darrick) include/linux/fs.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/include/linux/fs.h b/include/linux/fs.h index 79c413985305..751975b8b29b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1909,6 +1909,30 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ (inode)->i_rdev == WHITEOUT_DEV) +static inline bool IS_DEVDAX(struct inode *inode) +{ + if (!IS_ENABLED(CONFIG_DEV_DAX)) + return false; + if ((inode->i_flags & S_DAX) == 0) + return false; + /* regular files with S_DAX are filesystem-dax instances */ + if (!S_ISCHR(inode->i_mode)) + return false; + return true; +} + +static inline bool IS_FSDAX(struct inode *inode) +{ + if (!IS_ENABLED(CONFIG_FS_DAX)) + return false; + if ((inode->i_flags & S_DAX) == 0) + return false; + /* character devices with S_DAX are device-dax instances */ + if (S_ISCHR(inode->i_mode)) + return false; + return true; +} + static inline bool HAS_UNMAPPED_ID(struct inode *inode) { return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid); _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x244.google.com (mail-oi0-x244.google.com [IPv6:2607:f8b0:4003:c06::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 576D022352282 for ; Fri, 2 Mar 2018 10:31:31 -0800 (PST) Received: by mail-oi0-x244.google.com with SMTP id x12so7708360oie.13 for ; Fri, 02 Mar 2018 10:37:41 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20180302174530.GV19312@magnolia> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <151996282448.28483.10415125852182473579.stgit@dwillia2-desk3.amr.corp.intel.com> <20180302174530.GV19312@magnolia> From: Dan Williams Date: Fri, 2 Mar 2018 10:37:40 -0800 Message-ID: Subject: Re: [PATCH v5 02/12] dax: introduce IS_DEVDAX() and IS_FSDAX() List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: "Darrick J. Wong" Cc: Theodore Ts'o , Matthew Wilcox , linux-nvdimm , Linux Kernel Mailing List , stable , linux-xfs , Linux MM , Andreas Dilger , Alexander Viro , linux-fsdevel , Jan Kara , Christoph Hellwig List-ID: On Fri, Mar 2, 2018 at 9:45 AM, Darrick J. Wong wrote: > On Thu, Mar 01, 2018 at 07:53:44PM -0800, Dan Williams wrote: >> The current IS_DAX() helper that checks if a file is in DAX mode serves >> two purposes. It is a control flow branch condition for DAX vs >> non-DAX paths and it is a mechanism to perform dead code elimination. The >> dead code elimination is required in the CONFIG_FS_DAX=n case since >> there are symbols in fs/dax.c that will be elided. While the >> dead code elimination can be addressed with nop stubs for the fs/dax.c >> symbols that does not address the need for a DAX control flow helper >> where fs/dax.c symbols are not involved. >> >> Moreover, the control flow changes, in some cases, need to be cognizant >> of whether the DAX file is a typical file or a Device-DAX special file. >> Introduce IS_DEVDAX() and IS_FSDAX() to simultaneously address the >> file-type control flow and dead-code elimination use cases. IS_DAX() >> will be deleted after all sites are converted to use the file-type >> specific helper. >> >> Note, this change is also a pre-requisite for fixing the definition of >> the S_DAX inode flag in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case. >> The flag needs to be defined, non-zero, if either DAX facility is >> enabled. >> >> Cc: "Theodore Ts'o" >> Cc: Andreas Dilger >> Cc: Alexander Viro >> Cc: "Darrick J. Wong" >> Cc: linux-xfs@vger.kernel.org >> Cc: Matthew Wilcox >> Cc: Ross Zwisler >> Cc: >> Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") >> Reported-by: Jan Kara >> Reviewed-by: Jan Kara >> Signed-off-by: Dan Williams >> --- >> include/linux/fs.h | 22 ++++++++++++++++++++++ >> 1 file changed, 22 insertions(+) >> >> diff --git a/include/linux/fs.h b/include/linux/fs.h >> index 79c413985305..bd0c46880572 100644 >> --- a/include/linux/fs.h >> +++ b/include/linux/fs.h >> @@ -1909,6 +1909,28 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags >> #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ >> (inode)->i_rdev == WHITEOUT_DEV) >> >> +static inline bool IS_DEVDAX(struct inode *inode) >> +{ >> + if (!IS_ENABLED(CONFIG_DEV_DAX)) >> + return false; >> + if ((inode->i_flags & S_DAX) == 0) >> + return false; >> + if (!S_ISCHR(inode->i_mode)) >> + return false; >> + return true; >> +} >> + >> +static inline bool IS_FSDAX(struct inode *inode) >> +{ >> + if (!IS_ENABLED(CONFIG_FS_DAX)) >> + return false; > > I echo Jan's complaint from the last round that the dead code > elimination here is subtle, as compared to: > > #if IS_ENABLED(CONFIG_FS_DAX) > static inline bool IS_FSDAX(struct inode *inode) { ... } > #else > # define IS_FSDAX(inode) (false) > #endif > > But I guess even with that we're relying on dead code elimination higher > up in the call stack... If IS_FSDAX() was only a dead-code elimination mechanism rather than a runtime branch condition then I agree. Otherwise I think IS_ENABLED() is suitable and not subtle, especially when used in a header file. >> + if ((inode->i_flags & S_DAX) == 0) >> + return false; >> + if (S_ISCHR(inode->i_mode)) >> + return false; > > I'm curious, do we have character devices with S_DAX set? Yes, Device-DAX, see: ab68f2622136 /dev/dax, pmem: direct access to persistent memory > I /think/ we're expecting that only block/char devices and files will > ever have S_DAX set, so IS_FSDAX is only true for block devices and > files. Right? We had S_DAX on block-devices for a short while, but deleted it and went with the Device-DAX interface instead. So it's only regular files and /dev/daxX.Y nodes these days. > (A comment here about why S_ISCHR->false here would be helpful.) Ok. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 2 Mar 2018 09:45:30 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH v5 02/12] dax: introduce IS_DEVDAX() and IS_FSDAX() Message-ID: <20180302174530.GV19312@magnolia> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <151996282448.28483.10415125852182473579.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151996282448.28483.10415125852182473579.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: owner-linux-mm@kvack.org To: Dan Williams Cc: linux-nvdimm@lists.01.org, Theodore Ts'o , Andreas Dilger , Alexander Viro , linux-xfs@vger.kernel.org, Matthew Wilcox , Ross Zwisler , stable@vger.kernel.org, Jan Kara , hch@lst.de, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Thu, Mar 01, 2018 at 07:53:44PM -0800, Dan Williams wrote: > The current IS_DAX() helper that checks if a file is in DAX mode serves > two purposes. It is a control flow branch condition for DAX vs > non-DAX paths and it is a mechanism to perform dead code elimination. The > dead code elimination is required in the CONFIG_FS_DAX=n case since > there are symbols in fs/dax.c that will be elided. While the > dead code elimination can be addressed with nop stubs for the fs/dax.c > symbols that does not address the need for a DAX control flow helper > where fs/dax.c symbols are not involved. > > Moreover, the control flow changes, in some cases, need to be cognizant > of whether the DAX file is a typical file or a Device-DAX special file. > Introduce IS_DEVDAX() and IS_FSDAX() to simultaneously address the > file-type control flow and dead-code elimination use cases. IS_DAX() > will be deleted after all sites are converted to use the file-type > specific helper. > > Note, this change is also a pre-requisite for fixing the definition of > the S_DAX inode flag in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case. > The flag needs to be defined, non-zero, if either DAX facility is > enabled. > > Cc: "Theodore Ts'o" > Cc: Andreas Dilger > Cc: Alexander Viro > Cc: "Darrick J. Wong" > Cc: linux-xfs@vger.kernel.org > Cc: Matthew Wilcox > Cc: Ross Zwisler > Cc: > Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") > Reported-by: Jan Kara > Reviewed-by: Jan Kara > Signed-off-by: Dan Williams > --- > include/linux/fs.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 79c413985305..bd0c46880572 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1909,6 +1909,28 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags > #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ > (inode)->i_rdev == WHITEOUT_DEV) > > +static inline bool IS_DEVDAX(struct inode *inode) > +{ > + if (!IS_ENABLED(CONFIG_DEV_DAX)) > + return false; > + if ((inode->i_flags & S_DAX) == 0) > + return false; > + if (!S_ISCHR(inode->i_mode)) > + return false; > + return true; > +} > + > +static inline bool IS_FSDAX(struct inode *inode) > +{ > + if (!IS_ENABLED(CONFIG_FS_DAX)) > + return false; I echo Jan's complaint from the last round that the dead code elimination here is subtle, as compared to: #if IS_ENABLED(CONFIG_FS_DAX) static inline bool IS_FSDAX(struct inode *inode) { ... } #else # define IS_FSDAX(inode) (false) #endif But I guess even with that we're relying on dead code elimination higher up in the call stack... > + if ((inode->i_flags & S_DAX) == 0) > + return false; > + if (S_ISCHR(inode->i_mode)) > + return false; I'm curious, do we have character devices with S_DAX set? I /think/ we're expecting that only block/char devices and files will ever have S_DAX set, so IS_FSDAX is only true for block devices and files. Right? (A comment here about why S_ISCHR->false here would be helpful.) --D > + return true; > +} > + > static inline bool HAS_UNMAPPED_ID(struct inode *inode) > { > return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid); > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 46A6622485A9D for ; Thu, 1 Mar 2018 19:56:41 -0800 (PST) Subject: [PATCH v5 02/12] dax: introduce IS_DEVDAX() and IS_FSDAX() From: Dan Williams Date: Thu, 01 Mar 2018 19:53:44 -0800 Message-ID: <151996282448.28483.10415125852182473579.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Theodore Ts'o , Matthew Wilcox , "Darrick J. Wong" , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Andreas Dilger , Alexander Viro , linux-fsdevel@vger.kernel.org, Jan Kara , hch@lst.de List-ID: The current IS_DAX() helper that checks if a file is in DAX mode serves two purposes. It is a control flow branch condition for DAX vs non-DAX paths and it is a mechanism to perform dead code elimination. The dead code elimination is required in the CONFIG_FS_DAX=n case since there are symbols in fs/dax.c that will be elided. While the dead code elimination can be addressed with nop stubs for the fs/dax.c symbols that does not address the need for a DAX control flow helper where fs/dax.c symbols are not involved. Moreover, the control flow changes, in some cases, need to be cognizant of whether the DAX file is a typical file or a Device-DAX special file. Introduce IS_DEVDAX() and IS_FSDAX() to simultaneously address the file-type control flow and dead-code elimination use cases. IS_DAX() will be deleted after all sites are converted to use the file-type specific helper. Note, this change is also a pre-requisite for fixing the definition of the S_DAX inode flag in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case. The flag needs to be defined, non-zero, if either DAX facility is enabled. Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Alexander Viro Cc: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Jan Kara Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- include/linux/fs.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/include/linux/fs.h b/include/linux/fs.h index 79c413985305..bd0c46880572 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1909,6 +1909,28 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ (inode)->i_rdev == WHITEOUT_DEV) +static inline bool IS_DEVDAX(struct inode *inode) +{ + if (!IS_ENABLED(CONFIG_DEV_DAX)) + return false; + if ((inode->i_flags & S_DAX) == 0) + return false; + if (!S_ISCHR(inode->i_mode)) + return false; + return true; +} + +static inline bool IS_FSDAX(struct inode *inode) +{ + if (!IS_ENABLED(CONFIG_FS_DAX)) + return false; + if ((inode->i_flags & S_DAX) == 0) + return false; + if (S_ISCHR(inode->i_mode)) + return false; + return true; +} + static inline bool HAS_UNMAPPED_ID(struct inode *inode) { return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid); _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 8BD6022546B8C for ; Thu, 1 Mar 2018 19:57:25 -0800 (PST) Subject: [PATCH v5 10/12] fs, dax: kill IS_DAX() From: Dan Williams Date: Thu, 01 Mar 2018 19:54:28 -0800 Message-ID: <151996286805.28483.12933227722062678008.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Jan Kara , Matthew Wilcox , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: In preparation for fixing the broken definition of S_DAX in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case, convert all the remaining IS_DAX() usages to use explicit tests for FSDAX. Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- fs/iomap.c | 2 +- include/linux/dax.h | 2 +- include/linux/fs.h | 3 +-- 3 files changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/iomap.c b/fs/iomap.c index afd163586aa0..fe379d8949fd 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -377,7 +377,7 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, offset = pos & (PAGE_SIZE - 1); /* Within page */ bytes = min_t(loff_t, PAGE_SIZE - offset, count); - if (IS_DAX(inode)) + if (IS_FSDAX(inode)) status = iomap_dax_zero(pos, offset, bytes, iomap); else status = iomap_zero(inode, pos, offset, bytes, iomap); diff --git a/include/linux/dax.h b/include/linux/dax.h index 47edbce4fc52..ce520e932adc 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -124,7 +124,7 @@ static inline ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, static inline bool dax_mapping(struct address_space *mapping) { - return mapping->host && IS_DAX(mapping->host); + return mapping->host && IS_FSDAX(mapping->host); } struct writeback_control; diff --git a/include/linux/fs.h b/include/linux/fs.h index 33e859e7d100..b2b2e15d227b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1903,7 +1903,6 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags #define IS_IMA(inode) ((inode)->i_flags & S_IMA) #define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT) #define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC) -#define IS_DAX(inode) ((inode)->i_flags & S_DAX) #define IS_ENCRYPTED(inode) ((inode)->i_flags & S_ENCRYPTED) #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ @@ -3203,7 +3202,7 @@ extern int file_update_time(struct file *file); static inline bool io_is_direct(struct file *filp) { - return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host); + return (filp->f_flags & O_DIRECT) || IS_FSDAX(filp->f_mapping->host); } static inline bool vma_is_dax(struct vm_area_struct *vma) _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 49DAC223522B6 for ; Thu, 1 Mar 2018 19:56:52 -0800 (PST) Subject: [PATCH v5 04/12] ext2, dax: define ext2_dax_*() infrastructure in all cases From: Dan Williams Date: Thu, 01 Mar 2018 19:53:55 -0800 Message-ID: <151996283559.28483.2221179891176741624.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Jan Kara , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: In preparation for fixing S_DAX to be defined in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case, move the definition of these routines outside of the "#ifdef CONFIG_FS_DAX" guard. This is also a coding-style fix to move all ifdef handling to header files rather than in the source. The compiler will still be able to determine that all the related code can be discarded in the CONFIG_FS_DAX=n case. Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- fs/ext2/file.c | 8 -------- include/linux/dax.h | 10 ++++++++-- 2 files changed, 8 insertions(+), 10 deletions(-) diff --git a/fs/ext2/file.c b/fs/ext2/file.c index 1c7ea1bcddde..5ac98d074323 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -29,7 +29,6 @@ #include "xattr.h" #include "acl.h" -#ifdef CONFIG_FS_DAX static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct inode *inode = iocb->ki_filp->f_mapping->host; @@ -128,9 +127,6 @@ static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) vma->vm_flags |= VM_MIXEDMAP; return 0; } -#else -#define ext2_file_mmap generic_file_mmap -#endif /* * Called when filp is released. This happens when all file descriptors @@ -162,19 +158,15 @@ int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { -#ifdef CONFIG_FS_DAX if (IS_DAX(iocb->ki_filp->f_mapping->host)) return ext2_dax_read_iter(iocb, to); -#endif return generic_file_read_iter(iocb, to); } static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { -#ifdef CONFIG_FS_DAX if (IS_DAX(iocb->ki_filp->f_mapping->host)) return ext2_dax_write_iter(iocb, from); -#endif return generic_file_write_iter(iocb, from); } diff --git a/include/linux/dax.h b/include/linux/dax.h index 0185ecdae135..47edbce4fc52 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -93,8 +93,6 @@ void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); void dax_write_cache(struct dax_device *dax_dev, bool wc); bool dax_write_cache_enabled(struct dax_device *dax_dev); -ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, - const struct iomap_ops *ops); int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, pfn_t *pfnp, int *errp, const struct iomap_ops *ops); int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size, @@ -107,6 +105,8 @@ int dax_invalidate_mapping_entry_sync(struct address_space *mapping, int __dax_zero_page_range(struct block_device *bdev, struct dax_device *dax_dev, sector_t sector, unsigned int offset, unsigned int length); +ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops); #else static inline int __dax_zero_page_range(struct block_device *bdev, struct dax_device *dax_dev, sector_t sector, @@ -114,6 +114,12 @@ static inline int __dax_zero_page_range(struct block_device *bdev, { return -ENXIO; } + +static inline ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops) +{ + return -ENXIO; +} #endif static inline bool dax_mapping(struct address_space *mapping) _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 6A26922546B8C for ; Thu, 1 Mar 2018 19:57:35 -0800 (PST) Subject: [PATCH v5 12/12] vfio: disable filesystem-dax page pinning From: Dan Williams Date: Thu, 01 Mar 2018 19:54:39 -0800 Message-ID: <151996287917.28483.16157329534570989926.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Michal Hocko , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Alex Williamson , linux-fsdevel@vger.kernel.org, Christoph Hellwig List-ID: Filesystem-DAX is incompatible with 'longterm' page pinning. Without page cache indirection a DAX mapping maps filesystem blocks directly. This means that the filesystem must not modify a file's block map while any page in a mapping is pinned. In order to prevent the situation of userspace holding of filesystem operations indefinitely, disallow 'longterm' Filesystem-DAX mappings. RDMA has the same conflict and the plan there is to add a 'with lease' mechanism to allow the kernel to notify userspace that the mapping is being torn down for block-map maintenance. Perhaps something similar can be put in place for vfio. Note that xfs and ext4 still report: "DAX enabled. Warning: EXPERIMENTAL, use at your own risk" ...at mount time, and resolving the dax-dma-vs-truncate problem is one of the last hurdles to remove that designation. Acked-by: Alex Williamson Cc: Michal Hocko Cc: Christoph Hellwig Cc: kvm@vger.kernel.org Cc: Reported-by: Haozhong Zhang Tested-by: Haozhong Zhang Fixes: d475c6346a38 ("dax,ext2: replace XIP read and write with DAX I/O") Signed-off-by: Dan Williams --- drivers/vfio/vfio_iommu_type1.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index e30e29ae4819..45657e2b1ff7 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -338,11 +338,12 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, { struct page *page[1]; struct vm_area_struct *vma; + struct vm_area_struct *vmas[1]; int ret; if (mm == current->mm) { - ret = get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE), - page); + ret = get_user_pages_longterm(vaddr, 1, !!(prot & IOMMU_WRITE), + page, vmas); } else { unsigned int flags = 0; @@ -351,7 +352,18 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, down_read(&mm->mmap_sem); ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page, - NULL, NULL); + vmas, NULL); + /* + * The lifetime of a vaddr_get_pfn() page pin is + * userspace-controlled. In the fs-dax case this could + * lead to indefinite stalls in filesystem operations. + * Disallow attempts to pin fs-dax pages via this + * interface. + */ + if (ret > 0 && vma_is_fsdax(vmas[0])) { + ret = -EOPNOTSUPP; + put_page(page[0]); + } up_read(&mm->mmap_sem); } _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 042F4223522B6 for ; Thu, 1 Mar 2018 19:56:46 -0800 (PST) Subject: [PATCH v5 03/12] ext2, dax: finish implementing dax_sem helpers From: Dan Williams Date: Thu, 01 Mar 2018 19:53:50 -0800 Message-ID: <151996283005.28483.12905745385121745420.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Jan Kara , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: dax_sem_{up,down}_write_sem() allow the ext2 dax semaphore to be compiled out in the CONFIG_FS_DAX=n case. However there are still some open coded uses of the semaphore. Add dax_sem_{up_read,down_read}() and dax_sem_assert_held() helpers. Use them to convert all open-coded usages of the semaphore to the helpers. Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- fs/ext2/ext2.h | 6 ++++++ fs/ext2/file.c | 5 ++--- fs/ext2/inode.c | 4 +--- 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h index 032295e1d386..203c31dfe549 100644 --- a/fs/ext2/ext2.h +++ b/fs/ext2/ext2.h @@ -711,9 +711,15 @@ struct ext2_inode_info { #ifdef CONFIG_FS_DAX #define dax_sem_down_write(ext2_inode) down_write(&(ext2_inode)->dax_sem) #define dax_sem_up_write(ext2_inode) up_write(&(ext2_inode)->dax_sem) +#define dax_sem_assert_held(ei) WARN_ON(!rwsem_is_locked(&(ei)->dax_sem)) +#define dax_sem_down_read(ext2_inode) down_read(&(ext2_inode)->dax_sem) +#define dax_sem_up_read(ext2_inode) up_read(&(ext2_inode)->dax_sem) #else #define dax_sem_down_write(ext2_inode) #define dax_sem_up_write(ext2_inode) +#define dax_sem_assert_held(ext2_inode) +#define dax_sem_down_read(ext2_inode) +#define dax_sem_up_read(ext2_inode) #endif /* diff --git a/fs/ext2/file.c b/fs/ext2/file.c index 09640220fda8..1c7ea1bcddde 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -91,18 +91,17 @@ static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) static int ext2_dax_fault(struct vm_fault *vmf) { struct inode *inode = file_inode(vmf->vma->vm_file); - struct ext2_inode_info *ei = EXT2_I(inode); int ret; if (vmf->flags & FAULT_FLAG_WRITE) { sb_start_pagefault(inode->i_sb); file_update_time(vmf->vma->vm_file); } - down_read(&ei->dax_sem); + dax_sem_down_read(EXT2_I(inode)); ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, NULL, &ext2_iomap_ops); - up_read(&ei->dax_sem); + dax_sem_up_read(EXT2_I(inode)); if (vmf->flags & FAULT_FLAG_WRITE) sb_end_pagefault(inode->i_sb); return ret; diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 9b2ac55ac34f..4783db0e4873 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -1187,9 +1187,7 @@ static void __ext2_truncate_blocks(struct inode *inode, loff_t offset) blocksize = inode->i_sb->s_blocksize; iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb); -#ifdef CONFIG_FS_DAX - WARN_ON(!rwsem_is_locked(&ei->dax_sem)); -#endif + dax_sem_assert_held(ei); n = ext2_block_to_path(inode, iblock, offsets, NULL); if (n == 0) _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id B6EE622546B81 for ; Thu, 1 Mar 2018 19:57:02 -0800 (PST) Subject: [PATCH v5 06/12] ext2, dax: replace IS_DAX() with IS_FSDAX() From: Dan Williams Date: Thu, 01 Mar 2018 19:54:06 -0800 Message-ID: <151996284593.28483.4922911524438696817.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Jan Kara , Matthew Wilcox , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: In preparation for fixing the broken definition of S_DAX in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case, convert all IS_DAX() usages to use explicit tests for FSDAX since DAX is ambiguous. Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- fs/ext2/file.c | 6 +++--- fs/ext2/inode.c | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/ext2/file.c b/fs/ext2/file.c index 5ac98d074323..702a36df6c01 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -119,7 +119,7 @@ static const struct vm_operations_struct ext2_dax_vm_ops = { static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) { - if (!IS_DAX(file_inode(file))) + if (!IS_FSDAX(file_inode(file))) return generic_file_mmap(file, vma); file_accessed(file); @@ -158,14 +158,14 @@ int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { - if (IS_DAX(iocb->ki_filp->f_mapping->host)) + if (IS_FSDAX(iocb->ki_filp->f_mapping->host)) return ext2_dax_read_iter(iocb, to); return generic_file_read_iter(iocb, to); } static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { - if (IS_DAX(iocb->ki_filp->f_mapping->host)) + if (IS_FSDAX(iocb->ki_filp->f_mapping->host)) return ext2_dax_write_iter(iocb, from); return generic_file_write_iter(iocb, from); } diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 4783db0e4873..5352207da9d5 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -733,7 +733,7 @@ static int ext2_get_blocks(struct inode *inode, goto cleanup; } - if (IS_DAX(inode)) { + if (IS_FSDAX(inode)) { /* * We must unmap blocks before zeroing so that writeback cannot * overwrite zeros with stale data from block device page cache. @@ -940,7 +940,7 @@ ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter) loff_t offset = iocb->ki_pos; ssize_t ret; - if (WARN_ON_ONCE(IS_DAX(inode))) + if (WARN_ON_ONCE(IS_FSDAX(inode))) return -EIO; ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block); @@ -1294,7 +1294,7 @@ static int ext2_setsize(struct inode *inode, loff_t newsize) inode_dio_wait(inode); - if (IS_DAX(inode)) { + if (IS_FSDAX(inode)) { error = iomap_zero_range(inode, newsize, PAGE_ALIGN(newsize) - newsize, NULL, &ext2_iomap_ops); _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 7CC9121E256AF for ; Fri, 2 Mar 2018 14:46:02 -0800 (PST) Date: Fri, 2 Mar 2018 23:52:10 +0100 From: Christoph Hellwig Subject: Re: [PATCH v5 01/12] dax: fix vma_is_fsdax() helper Message-ID: <20180302225210.GB31240@lst.de> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <151996281881.28483.2616406435517031167.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <151996281881.28483.2616406435517031167.stgit@dwillia2-desk3.amr.corp.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: Jane Chu , Jan Kara , linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Gerd Rausch , linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: Looks good, Reviewed-by: Christoph Hellwig _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id D49E72255D6FE for ; Thu, 1 Mar 2018 19:56:35 -0800 (PST) Subject: [PATCH v5 01/12] dax: fix vma_is_fsdax() helper From: Dan Williams Date: Thu, 01 Mar 2018 19:53:38 -0800 Message-ID: <151996281881.28483.2616406435517031167.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: Jane Chu , Jan Kara , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Gerd Rausch , linux-fsdevel@vger.kernel.org, hch@lst.de List-ID: Gerd reports that ->i_mode may contain other bits besides S_IFCHR. Use S_ISCHR() instead. Otherwise, get_user_pages_longterm() may fail on device-dax instances when those are meant to be explicitly allowed. Fixes: 2bb6d2837083 ("mm: introduce get_user_pages_longterm") Cc: Reported-by: Gerd Rausch Acked-by: Jane Chu Reported-by: Haozhong Zhang Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- include/linux/fs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 2a815560fda0..79c413985305 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3198,7 +3198,7 @@ static inline bool vma_is_fsdax(struct vm_area_struct *vma) if (!vma_is_dax(vma)) return false; inode = file_inode(vma->vm_file); - if (inode->i_mode == S_IFCHR) + if (S_ISCHR(inode->i_mode)) return false; /* device-dax */ return true; } _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x243.google.com (mail-oi0-x243.google.com [IPv6:2607:f8b0:4003:c06::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id C3BB021F0DA76 for ; Fri, 2 Mar 2018 18:13:07 -0800 (PST) Received: by mail-oi0-x243.google.com with SMTP id u73so8433470oie.3 for ; Fri, 02 Mar 2018 18:19:17 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <20180302221020.GA30722@lst.de> <20180302225734.GE31240@lst.de> From: Dan Williams Date: Fri, 2 Mar 2018 18:19:16 -0800 Message-ID: Subject: Re: [PATCH v5 00/12] vfio, dax: prevent long term filesystem-dax pins and other fixes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Christoph Hellwig Cc: Michal Hocko , Jan Kara , Matthew Wilcox , KVM list , "Darrick J. Wong" , linux-nvdimm , Linux Kernel Mailing List , stable , linux-xfs , Linux MM , Alex Williamson , Gerd Rausch , Andreas Dilger , Alexander Viro , linux-fsdevel , Theodore Ts'o List-ID: On Fri, Mar 2, 2018 at 3:49 PM, Dan Williams wrote: > On Fri, Mar 2, 2018 at 2:57 PM, Christoph Hellwig wrote: >> On Fri, Mar 02, 2018 at 02:21:40PM -0800, Dan Williams wrote: >>> They are indeed a hodge-podge. The problem is that the current >>> IS_DAX() is broken. So I'd like to propose fixing IS_DAX() with >>> IS_FSDAX() + IS_DEVDAX() for 4.16-rc4 and queue up these wider reworks >>> you propose for the next merge window. >> >> The only thing broken about IS_DAX are the code elimination games >> based on the CONFIG_* flags. Remove those and just add proper stubs >> for the dax routines and everything will be fine for now until we can >> kill that inode flag. >> >> IS_FSDAX and IS_DEVDAX on the other hand are a giant mess that isn't >> helping anyone. > > Ok, I'll take another shot at something suitable for 4.16, but without > these new helpers... I'll drop patches 2-11 for now, and just get the high priority fixes in for the next rc. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x244.google.com (mail-oi0-x244.google.com [IPv6:2607:f8b0:4003:c06::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 878FD21E082B8 for ; Fri, 2 Mar 2018 15:43:36 -0800 (PST) Received: by mail-oi0-x244.google.com with SMTP id c12so8256967oic.7 for ; Fri, 02 Mar 2018 15:49:46 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20180302225734.GE31240@lst.de> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <20180302221020.GA30722@lst.de> <20180302225734.GE31240@lst.de> From: Dan Williams Date: Fri, 2 Mar 2018 15:49:45 -0800 Message-ID: Subject: Re: [PATCH v5 00/12] vfio, dax: prevent long term filesystem-dax pins and other fixes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Christoph Hellwig Cc: Jane Chu , Michal Hocko , Jan Kara , Matthew Wilcox , KVM list , "Darrick J. Wong" , linux-nvdimm , Linux Kernel Mailing List , stable , linux-xfs , Linux MM , Alex Williamson , Gerd Rausch , Andreas Dilger , Alexander Viro , linux-fsdevel , Theodore Ts'o List-ID: On Fri, Mar 2, 2018 at 2:57 PM, Christoph Hellwig wrote: > On Fri, Mar 02, 2018 at 02:21:40PM -0800, Dan Williams wrote: >> They are indeed a hodge-podge. The problem is that the current >> IS_DAX() is broken. So I'd like to propose fixing IS_DAX() with >> IS_FSDAX() + IS_DEVDAX() for 4.16-rc4 and queue up these wider reworks >> you propose for the next merge window. > > The only thing broken about IS_DAX are the code elimination games > based on the CONFIG_* flags. Remove those and just add proper stubs > for the dax routines and everything will be fine for now until we can > kill that inode flag. > > IS_FSDAX and IS_DEVDAX on the other hand are a giant mess that isn't > helping anyone. Ok, I'll take another shot at something suitable for 4.16, but without these new helpers... _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 525B021E08291 for ; Fri, 2 Mar 2018 14:51:26 -0800 (PST) Date: Fri, 2 Mar 2018 23:57:34 +0100 From: Christoph Hellwig Subject: Re: [PATCH v5 00/12] vfio, dax: prevent long term filesystem-dax pins and other fixes Message-ID: <20180302225734.GE31240@lst.de> References: <151996281307.28483.12343847096989509127.stgit@dwillia2-desk3.amr.corp.intel.com> <20180302221020.GA30722@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: Jane Chu , Michal Hocko , Jan Kara , Matthew Wilcox