[PATCH 09/23] md: rewrite md_setup_drive to avoid ioctls

Christoph Hellwig
2020-07-14T19:10:47Z

md_setup_drive knows it works with md devices, so it is rather pointless
to open a file descriptor and issue ioctls. Just call directly into the
relevant low-level md routines after getting a handle to the device using
blkdev_get_by_dev instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
---
drivers/md/md-autodetect.c | 127 ++++++++++++++++---------------------
drivers/md/md.c | 20 +++---
drivers/md/md.h | 6 ++
3 files changed, 71 insertions(+), 82 deletions(-)

diff --git a/drivers/md/md-autodetect.c b/drivers/md/md-autodetect.c
index a43a8f1580584c..5b24b5616d3acc 100644
--- a/drivers/md/md-autodetect.c
+++ b/drivers/md/md-autodetect.c
@@ -2,7 +2,6 @@
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
-#include <linux/syscalls.h>
#include <linux/mount.h>
#include <linux/major.h>
#include <linux/delay.h>
@@ -120,37 +119,29 @@ static int __init md_setup(char *str)
return 1;
}

-static inline int create_dev(char *name, dev_t dev)
-{
- ksys_unlink(name);
- return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
-}
-
static void __init md_setup_drive(struct md_setup_args *args)
{
- int minor, i, partitioned;
- dev_t dev;
- dev_t devices[MD_SB_DISKS+1];
- int fd;
- int err = 0;
- char *devname;
- mdu_disk_info_t dinfo;
+ char *devname = args->device_names;
+ dev_t devices[MD_SB_DISKS + 1], mdev;
+ struct mdu_array_info_s ainfo = { };
+ struct block_device *bdev;
+ struct mddev *mddev;
+ int err = 0, i;
char name[16];

- minor = args->minor;
- partitioned = args->partitioned;
- devname = args->device_names;
+ if (args->partitioned) {
+ mdev = MKDEV(mdp_major, args->minor << MdpMinorShift);
+ sprintf(name, "md_d%d", args->minor);
+ } else {
+ mdev = MKDEV(MD_MAJOR, args->minor);
+ sprintf(name, "md%d", args->minor);
+ }

- sprintf(name, "/dev/md%s%d", partitioned?"_d":"", minor);
- if (partitioned)
- dev = MKDEV(mdp_major, minor << MdpMinorShift);
- else
- dev = MKDEV(MD_MAJOR, minor);
- create_dev(name, dev);
for (i = 0; i < MD_SB_DISKS && devname != NULL; i++) {
struct kstat stat;
char *p;
char comp_name[64];
+ dev_t dev;

p = strchr(devname, ',');
if (p)
@@ -163,7 +154,7 @@ static void __init md_setup_drive(struct md_setup_args *args)
if (vfs_stat(comp_name, &stat) == 0 && S_ISBLK(stat.mode))
dev = new_decode_dev(stat.rdev);
if (!dev) {
- printk(KERN_WARNING "md: Unknown device name: %s\n", devname);
+ pr_warn("md: Unknown device name: %s\n", devname);
break;
}

@@ -175,68 +166,64 @@ static void __init md_setup_drive(struct md_setup_args *args)
if (!i)
return;

- printk(KERN_INFO "md: Loading md%s%d: %s\n",
- partitioned ? "_d" : "", minor,
- args->device_names);
+ pr_info("md: Loading %s: %s\n", name, args->device_names);

- fd = ksys_open(name, 0, 0);
- if (fd < 0) {
- printk(KERN_ERR "md: open failed - cannot start "
- "array %s\n", name);
+ bdev = blkdev_get_by_dev(mdev, FMODE_READ, NULL);
+ if (IS_ERR(bdev)) {
+ pr_err("md: open failed - cannot start array %s\n", name);
return;
}
- if (ksys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
- printk(KERN_WARNING
- "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
- minor);
- ksys_close(fd);
- return;
+ mddev = bdev->bd_disk->private_data;
+
+ err = mddev_lock(mddev);
+ if (err) {
+ pr_err("md: failed to lock array %s\n", name);
+ goto out_blkdev_put;
+ }
+
+ if (!list_empty(&mddev->disks) || mddev->raid_disks) {
+ pr_warn("md: Ignoring %s, already autodetected. (Use raid=noautodetect)\n",
+ name);
+ goto out_unlock;
}

if (args->level != LEVEL_NONE) {
/* non-persistent */
- mdu_array_info_t ainfo;
ainfo.level = args->level;
- ainfo.size = 0;
- ainfo.nr_disks =0;
- ainfo.raid_disks =0;
- while (devices[ainfo.raid_disks])
- ainfo.raid_disks++;
- ainfo.md_minor =minor;
+ ainfo.md_minor = args->minor;
ainfo.not_persistent = 1;
-
ainfo.state = (1 << MD_SB_CLEAN);
- ainfo.layout = 0;
ainfo.chunk_size = args->chunk;
- err = ksys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
- for (i = 0; !err && i <= MD_SB_DISKS; i++) {
- dev = devices[i];
- if (!dev)
- break;
+ while (devices[ainfo.raid_disks])
+ ainfo.raid_disks++;
+ }
+
+ err = md_set_array_info(mddev, &ainfo);
+
+ for (i = 0; i <= MD_SB_DISKS && devices[i]; i++) {
+ struct mdu_disk_info_s dinfo = {
+ .major = MAJOR(devices[i]),
+ .minor = MINOR(devices[i]),
+ };
+
+ if (args->level != LEVEL_NONE) {
dinfo.number = i;
dinfo.raid_disk = i;
- dinfo.state = (1<<MD_DISK_ACTIVE)|(1<<MD_DISK_SYNC);
- dinfo.major = MAJOR(dev);
- dinfo.minor = MINOR(dev);
- err = ksys_ioctl(fd, ADD_NEW_DISK,
- (long)&dinfo);
- }
- } else {
- /* persistent */
- for (i = 0; i <= MD_SB_DISKS; i++) {
- dev = devices[i];
- if (!dev)
- break;
- dinfo.major = MAJOR(dev);
- dinfo.minor = MINOR(dev);
- ksys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
+ dinfo.state =
+ (1 << MD_DISK_ACTIVE) | (1 << MD_DISK_SYNC);
}
+
+ md_add_new_disk(mddev, &dinfo);
}
+
if (!err)
- err = ksys_ioctl(fd, RUN_ARRAY, 0);
+ err = do_md_run(mddev);
if (err)
- printk(KERN_WARNING "md: starting md%d failed\n", minor);
- ksys_close(fd);
+ pr_warn("md: starting %s failed\n", name);
+out_unlock:
+ mddev_unlock(mddev);
+out_blkdev_put:
+ blkdev_put(bdev, FMODE_READ);
}

static int __init raid_setup(char *str)
@@ -286,8 +273,6 @@ void __init md_run_setup(void)
{
int ent;

- create_dev("/dev/md0", MKDEV(MD_MAJOR, 0));
-
if (raid_noautodetect)
printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=autodetect will force)\n");
else
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6e9a48da474848..9960cfeb59a50c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4368,7 +4368,6 @@ array_state_show(struct mddev *mddev, char *page)

static int do_md_stop(struct mddev *mddev, int ro, struct block_device *bdev);
static int md_set_readonly(struct mddev *mddev, struct block_device *bdev);
-static int do_md_run(struct mddev *mddev);
static int restart_array(struct mddev *mddev);

static ssize_t
@@ -6015,7 +6014,7 @@ int md_run(struct mddev *mddev)
}
EXPORT_SYMBOL_GPL(md_run);

-static int do_md_run(struct mddev *mddev)
+int do_md_run(struct mddev *mddev)
{
int err;

@@ -6651,7 +6650,7 @@ static int get_disk_info(struct mddev *mddev, void __user * arg)
return 0;
}

-static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
+int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
{
char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
struct md_rdev *rdev;
@@ -6697,7 +6696,7 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
}

/*
- * add_new_disk can be used once the array is assembled
+ * md_add_new_disk can be used once the array is assembled
* to add "hot spares". They must already have a superblock
* written
*/
@@ -6810,7 +6809,7 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
return err;
}

- /* otherwise, add_new_disk is only allowed
+ /* otherwise, md_add_new_disk is only allowed
* for major_version==0 superblocks
*/
if (mddev->major_version != 0) {
@@ -7055,7 +7054,7 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
}

/*
- * set_array_info is used two different ways
+ * md_set_array_info is used two different ways
* The original usage is when creating a new array.
* In this usage, raid_disks is > 0 and it together with
* level, size, not_persistent,layout,chunksize determine the
@@ -7067,9 +7066,8 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
* The minor and patch _version numbers are also kept incase the
* super_block handler wishes to interpret them.
*/
-static int set_array_info(struct mddev *mddev, mdu_array_info_t *info)
+int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info)
{
-
if (info->raid_disks == 0) {
/* just setting version number for superblock loading */
if (info->major_version < 0 ||
@@ -7560,7 +7558,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
err = -EBUSY;
goto unlock;
}
- err = set_array_info(mddev, &info);
+ err = md_set_array_info(mddev, &info);
if (err) {
pr_warn("md: couldn't set array info. %d\n", err);
goto unlock;
@@ -7614,7 +7612,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
/* Need to clear read-only for this */
break;
else
- err = add_new_disk(mddev, &info);
+ err = md_add_new_disk(mddev, &info);
goto unlock;
}
break;
@@ -7682,7 +7680,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
if (copy_from_user(&info, argp, sizeof(info)))
err = -EFAULT;
else
- err = add_new_disk(mddev, &info);
+ err = md_add_new_disk(mddev, &info);
goto unlock;
}

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 6f8fff77ce10a5..7ee81aa2eac862 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -801,7 +801,13 @@ static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio
mddev->queue->limits.max_write_zeroes_sectors = 0;
}

+struct mdu_array_info_s;
+struct mdu_disk_info_s;
+
extern int mdp_major;
void md_autostart_arrays(int part);
+int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info);
+int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info);
+int do_md_run(struct mddev *mddev);

#endif /* _MD_MD_H */
--
2.27.0