Thread (4 messages) 4 messages, 2 authors, 2023-06-07

Re: [PATCH 28/31] block: replace fmode_t with a block-specific type for block open flags

From: Christian Brauner <brauner@kernel.org>
Date: 2023-06-07 09:21:36
Also in: dm-devel, linux-bcache, linux-btrfs, linux-f2fs-devel, linux-fsdevel, linux-nvme, linux-pm, linux-scsi, linux-um

On Tue, Jun 06, 2023 at 09:39:47AM +0200, Christoph Hellwig wrote:
The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE.  Define a new
and FMODE_EXCL afaict
quoted hunk
blk_mode_t instead for use in blkdev_get_by_*, ->open and ->ioctl and
stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/um/drivers/ubd_kern.c          |  8 +++---
 arch/xtensa/platforms/iss/simdisk.c |  2 +-
 block/bdev.c                        | 32 +++++++++++-----------
 block/blk-zoned.c                   |  8 +++---
 block/blk.h                         | 11 ++++----
 block/fops.c                        | 26 +++++++++++++-----
 block/genhd.c                       |  8 +++---
 block/ioctl.c                       | 42 +++++++++--------------------
 drivers/block/amiflop.c             | 12 ++++-----
 drivers/block/aoe/aoeblk.c          |  4 +--
 drivers/block/ataflop.c             | 25 +++++++++--------
 drivers/block/drbd/drbd_main.c      |  7 ++---
 drivers/block/drbd/drbd_nl.c        |  2 +-
 drivers/block/floppy.c              | 28 +++++++++----------
 drivers/block/loop.c                | 22 +++++++--------
 drivers/block/mtip32xx/mtip32xx.c   |  4 +--
 drivers/block/nbd.c                 |  4 +--
 drivers/block/pktcdvd.c             | 17 ++++++------
 drivers/block/rbd.c                 |  2 +-
 drivers/block/rnbd/rnbd-clt.c       |  4 +--
 drivers/block/rnbd/rnbd-srv.c       |  4 +--
 drivers/block/sunvdc.c              |  2 +-
 drivers/block/swim.c                | 16 +++++------
 drivers/block/swim3.c               | 24 ++++++++---------
 drivers/block/ublk_drv.c            |  2 +-
 drivers/block/xen-blkback/xenbus.c  |  2 +-
 drivers/block/xen-blkfront.c        |  2 +-
 drivers/block/z2ram.c               |  2 +-
 drivers/block/zram/zram_drv.c       |  6 ++---
 drivers/cdrom/cdrom.c               |  4 +--
 drivers/cdrom/gdrom.c               |  4 +--
 drivers/md/bcache/bcache.h          |  2 +-
 drivers/md/bcache/request.c         |  4 +--
 drivers/md/bcache/super.c           |  6 ++---
 drivers/md/dm-cache-target.c        | 12 ++++-----
 drivers/md/dm-clone-target.c        | 10 +++----
 drivers/md/dm-core.h                |  7 +++--
 drivers/md/dm-era-target.c          |  6 +++--
 drivers/md/dm-ioctl.c               | 10 +++----
 drivers/md/dm-snap.c                |  4 +--
 drivers/md/dm-table.c               | 11 ++++----
 drivers/md/dm-thin.c                |  9 ++++---
 drivers/md/dm-verity-fec.c          |  2 +-
 drivers/md/dm-verity-target.c       |  6 ++---
 drivers/md/dm.c                     | 10 +++----
 drivers/md/dm.h                     |  2 +-
 drivers/md/md.c                     |  8 +++---
 drivers/mmc/core/block.c            |  8 +++---
 drivers/mtd/devices/block2mtd.c     |  4 +--
 drivers/mtd/mtd_blkdevs.c           |  4 +--
 drivers/mtd/ubi/block.c             |  5 ++--
 drivers/nvme/host/core.c            |  2 +-
 drivers/nvme/host/ioctl.c           |  8 +++---
 drivers/nvme/host/multipath.c       |  2 +-
 drivers/nvme/host/nvme.h            |  4 +--
 drivers/nvme/target/io-cmd-bdev.c   |  2 +-
 drivers/s390/block/dasd.c           |  6 ++---
 drivers/s390/block/dasd_genhd.c     |  3 ++-
 drivers/s390/block/dasd_int.h       |  3 ++-
 drivers/s390/block/dasd_ioctl.c     |  2 +-
 drivers/s390/block/dcssblk.c        |  4 +--
 drivers/scsi/sd.c                   | 19 ++++++-------
 drivers/scsi/sr.c                   | 10 +++----
 drivers/target/target_core_iblock.c |  5 ++--
 drivers/target/target_core_pscsi.c  |  4 +--
 fs/btrfs/dev-replace.c              |  2 +-
 fs/btrfs/super.c                    |  4 +--
 fs/btrfs/volumes.c                  | 16 +++++------
 fs/btrfs/volumes.h                  |  4 +--
 fs/erofs/super.c                    |  2 +-
 fs/ext4/super.c                     |  2 +-
 fs/jfs/jfs_logmgr.c                 |  2 +-
 fs/nfs/blocklayout/dev.c            |  5 ++--
 fs/ocfs2/cluster/heartbeat.c        |  3 ++-
 fs/reiserfs/journal.c               |  4 +--
 fs/xfs/xfs_super.c                  |  2 +-
 include/linux/blkdev.h              | 30 ++++++++++++++++-----
 include/linux/cdrom.h               |  3 ++-
 include/linux/device-mapper.h       |  8 +++---
 kernel/power/swap.c                 |  6 ++---
 mm/swapfile.c                       |  2 +-
 81 files changed, 324 insertions(+), 311 deletions(-)
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 20c1a16199c503..50206feac577d5 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -108,9 +108,9 @@ static inline void ubd_set_bit(__u64 bit, unsigned char *data)
 static DEFINE_MUTEX(ubd_lock);
 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
 
-static int ubd_open(struct gendisk *disk, fmode_t mode);
+static int ubd_open(struct gendisk *disk, blk_mode_t mode);
 static void ubd_release(struct gendisk *disk);
-static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
+static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode,
 		     unsigned int cmd, unsigned long arg);
 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
 
@@ -1154,7 +1154,7 @@ static int __init ubd_driver_init(void){
 
 device_initcall(ubd_driver_init);
 
-static int ubd_open(struct gendisk *disk, fmode_t mode)
+static int ubd_open(struct gendisk *disk, blk_mode_t mode)
 {
 	struct ubd *ubd_dev = disk->private_data;
 	int err = 0;
@@ -1389,7 +1389,7 @@ static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 	return 0;
 }
 
-static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
+static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode,
 		     unsigned int cmd, unsigned long arg)
 {
 	struct ubd *ubd_dev = bdev->bd_disk->private_data;
diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c
index 2ad9da3de0d90f..178cf96ca10acb 100644
--- a/arch/xtensa/platforms/iss/simdisk.c
+++ b/arch/xtensa/platforms/iss/simdisk.c
@@ -120,7 +120,7 @@ static void simdisk_submit_bio(struct bio *bio)
 	bio_endio(bio);
 }
 
-static int simdisk_open(struct gendisk *disk, fmode_t mode)
+static int simdisk_open(struct gendisk *disk, blk_mode_t mode)
 {
 	struct simdisk *dev = disk->private_data;
 
diff --git a/block/bdev.c b/block/bdev.c
index db63e5bcc46ffa..bd558a9ba3cd97 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -93,7 +93,7 @@ EXPORT_SYMBOL(invalidate_bdev);
  * Drop all buffers & page cache for given bdev range. This function bails
  * with error if bdev has other exclusive owner (such as filesystem).
  */
-int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
+int truncate_bdev_range(struct block_device *bdev, blk_mode_t mode,
 			loff_t lstart, loff_t lend)
 {
 	/*
@@ -101,14 +101,14 @@ int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
 	 * while we discard the buffer cache to avoid discarding buffers
 	 * under live filesystem.
 	 */
-	if (!(mode & FMODE_EXCL)) {
+	if (!(mode & BLK_OPEN_EXCL)) {
 		int err = bd_prepare_to_claim(bdev, truncate_bdev_range, NULL);
 		if (err)
 			goto invalidate;
 	}
 
 	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
-	if (!(mode & FMODE_EXCL))
+	if (!(mode & BLK_OPEN_EXCL))
 		bd_abort_claiming(bdev, truncate_bdev_range);
 	return 0;
 
@@ -647,7 +647,7 @@ static void blkdev_flush_mapping(struct block_device *bdev)
 	bdev_write_inode(bdev);
 }
 
-static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
+static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
 	int ret;
@@ -679,7 +679,7 @@ static void blkdev_put_whole(struct block_device *bdev)
 		bdev->bd_disk->fops->release(bdev->bd_disk);
 }
 
-static int blkdev_get_part(struct block_device *part, fmode_t mode)
+static int blkdev_get_part(struct block_device *part, blk_mode_t mode)
 {
 	struct gendisk *disk = part->bd_disk;
 	int ret;
@@ -743,11 +743,11 @@ void blkdev_put_no_open(struct block_device *bdev)
 {
 	put_device(&bdev->bd_device);
 }
-
+	
nit: This is whitespace damage, I think. There's a trailing tab.
quoted hunk
 /**
  * blkdev_get_by_dev - open a block device by device number
  * @dev: device number of block device to open
- * @mode: FMODE_* mask
+ * @mode: open mode (BLK_OPEN_*)
  * @holder: exclusive holder identifier
  * @hops: holder operations
  *
@@ -765,7 +765,7 @@ void blkdev_put_no_open(struct block_device *bdev)
  * RETURNS:
  * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
-struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
+struct block_device *blkdev_get_by_dev(dev_t dev, blk_mode_t mode, void *holder,
 		const struct blk_holder_ops *hops)
 {
 	bool unblock_events = true;
@@ -775,8 +775,8 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
 
 	ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
 			MAJOR(dev), MINOR(dev),
-			((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
-			((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
+			((mode & BLK_OPEN_READ) ? DEVCG_ACC_READ : 0) |
+			((mode & BLK_OPEN_WRITE) ? DEVCG_ACC_WRITE : 0));
 	if (ret)
 		return ERR_PTR(ret);
 
@@ -786,12 +786,12 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
 	disk = bdev->bd_disk;
 
 	if (holder) {
-		mode |= FMODE_EXCL;
+		mode |= BLK_OPEN_EXCL;
 		ret = bd_prepare_to_claim(bdev, holder, hops);
 		if (ret)
 			goto put_blkdev;
 	} else {
-		if (WARN_ON_ONCE(mode & FMODE_EXCL)) {
+		if (WARN_ON_ONCE(mode & BLK_OPEN_EXCL)) {
 			ret = -EIO;
 			goto put_blkdev;
 		}
@@ -821,7 +821,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
 		 * writeable reference is too fragile given the way @mode is
 		 * used in blkdev_get/put().
 		 */
-		if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
+		if ((mode & BLK_OPEN_WRITE) && !bdev->bd_write_holder &&
 		    (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) {
 			bdev->bd_write_holder = true;
 			unblock_events = false;
@@ -848,7 +848,7 @@ EXPORT_SYMBOL(blkdev_get_by_dev);
 /**
  * blkdev_get_by_path - open a block device by name
  * @path: path to the block device to open
- * @mode: FMODE_* mask
+ * @mode: open mode (BLK_OPEN_*)
  * @holder: exclusive holder identifier
  *
  * Open the block device described by the device file at @path.  If @holder is
@@ -861,7 +861,7 @@ EXPORT_SYMBOL(blkdev_get_by_dev);
  * RETURNS:
  * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
-struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
+struct block_device *blkdev_get_by_path(const char *path, blk_mode_t mode,
 		void *holder, const struct blk_holder_ops *hops)
 {
 	struct block_device *bdev;
@@ -873,7 +873,7 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 		return ERR_PTR(error);
 
 	bdev = blkdev_get_by_dev(dev, mode, holder, hops);
-	if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+	if (!IS_ERR(bdev) && (mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
 		blkdev_put(bdev, holder);
 		return ERR_PTR(-EACCES);
 	}
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 02cc2c629ac9be..0f9f97cdddd99c 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -356,8 +356,8 @@ int blkdev_report_zones_ioctl(struct block_device *bdev, unsigned int cmd,
 	return 0;
 }
 
-static int blkdev_truncate_zone_range(struct block_device *bdev, fmode_t mode,
-				      const struct blk_zone_range *zrange)
+static int blkdev_truncate_zone_range(struct block_device *bdev,
+		blk_mode_t mode, const struct blk_zone_range *zrange)
 {
 	loff_t start, end;
 
@@ -376,7 +376,7 @@ static int blkdev_truncate_zone_range(struct block_device *bdev, fmode_t mode,
  * BLKRESETZONE, BLKOPENZONE, BLKCLOSEZONE and BLKFINISHZONE ioctl processing.
  * Called from blkdev_ioctl.
  */
-int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
+int blkdev_zone_mgmt_ioctl(struct block_device *bdev, blk_mode_t mode,
 			   unsigned int cmd, unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
@@ -390,7 +390,7 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
 	if (!bdev_is_zoned(bdev))
 		return -ENOTTY;
 
-	if (!(mode & FMODE_WRITE))
+	if (!(mode & BLK_OPEN_WRITE))
 		return -EBADF;
 
 	if (copy_from_user(&zrange, argp, sizeof(struct blk_zone_range)))
diff --git a/block/blk.h b/block/blk.h
index e28d5d67d31a28..768852a84fefb3 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -396,7 +396,7 @@ void disk_free_zone_bitmaps(struct gendisk *disk);
 void disk_clear_zone_settings(struct gendisk *disk);
 int blkdev_report_zones_ioctl(struct block_device *bdev, unsigned int cmd,
 		unsigned long arg);
-int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
+int blkdev_zone_mgmt_ioctl(struct block_device *bdev, blk_mode_t mode,
 		unsigned int cmd, unsigned long arg);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline void disk_free_zone_bitmaps(struct gendisk *disk) {}
@@ -407,7 +407,7 @@ static inline int blkdev_report_zones_ioctl(struct block_device *bdev,
 	return -ENOTTY;
 }
 static inline int blkdev_zone_mgmt_ioctl(struct block_device *bdev,
-		fmode_t mode, unsigned int cmd, unsigned long arg)
+		blk_mode_t mode, unsigned int cmd, unsigned long arg)
 {
 	return -ENOTTY;
 }
@@ -451,7 +451,7 @@ static inline void bio_release_page(struct bio *bio, struct page *page)
 
 struct request_queue *blk_alloc_queue(int node_id);
 
-int disk_scan_partitions(struct gendisk *disk, fmode_t mode);
+int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode);
 
 int disk_alloc_events(struct gendisk *disk);
 void disk_add_events(struct gendisk *disk);
@@ -466,8 +466,9 @@ extern struct device_attribute dev_attr_events_poll_msecs;
 
 extern struct attribute_group blk_trace_attr_group;
 
-int truncate_bdev_range(struct block_device *bdev, fmode_t mode, loff_t lstart,
-		loff_t lend);
+blk_mode_t file_to_blk_mode(struct file *file);
+int truncate_bdev_range(struct block_device *bdev, blk_mode_t mode,
+		loff_t lstart, loff_t lend);
 long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);
 long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);
 
diff --git a/block/fops.c b/block/fops.c
index 9f26e25bafa172..928c37a214f785 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -470,6 +470,24 @@ static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
 	return error;
 }
 
+blk_mode_t file_to_blk_mode(struct file *file)
+{
+	blk_mode_t mode = 0;
+
+	if (file->f_mode & FMODE_READ)
+		mode |= BLK_OPEN_READ;
+	if (file->f_mode & FMODE_WRITE)
+		mode |= BLK_OPEN_WRITE;
+	if (file->f_mode & FMODE_EXCL)
+		mode |= BLK_OPEN_EXCL;
+	if ((file->f_flags & O_ACCMODE) == 3)
I really don't like magic numbers like this.

Groan, O_RDONLY being defined as 0 strikes again...
Becuase of this quirk we internally map

O_RDONLY(0) -> FMODE_READ(1)
O_WRONLY(1) -> FMODE_WRITE(2)
O_RDWR(3)   -> (FMODE_READ | FMODE_WRITE)

so checking for the raw 3 here is confusing in addition to being a magic
number as it could give the impression that what's checked here is
(O_WRONLY | O_RDWR) which doesn't make sense...

So my perference would be in descending order of preference:

(file->f_flags & O_ACCMODE) == (FMODE_READ | FMODE_WRITE)

or while a little less clear but informative enough for people familiar
with the O_RDONLY quirk:

if ((file->f_flags & O_ACCMODE) == O_ACCMODE)
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help