[PATCH 5/9] pstore/blk: simplify the block device open / close path
Christoph Hellwig
hch at lst.de
Fri Oct 16 09:20:43 EDT 2020
Remove the pointless psblk_get_bdev and psblk_put_bdev helper,
and don't bother holding pstore_blk_lock over the block device
open / close interactions given that they only happen first thing
during module init and last thing during module exit. Also don't
bother with unregistering a zone info that did not come from the
actually block backed code, as users like mtd have to unregister
it themselves already.
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
fs/pstore/blk.c | 156 ++++++++++++------------------------------------
1 file changed, 38 insertions(+), 118 deletions(-)
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 3a2214ecf942ae..a8aa56cba96d59 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -91,12 +91,6 @@ static DEFINE_MUTEX(pstore_blk_lock);
static struct block_device *psblk_bdev;
static struct pstore_zone_info *pstore_zone_info;
-struct bdev_info {
- dev_t devt;
- sector_t nr_sects;
- sector_t start_sect;
-};
-
#define check_size(name, alignsize) ({ \
long _##name_ = (name); \
_##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \
@@ -205,75 +199,6 @@ void unregister_pstore_device(struct pstore_device_info *dev)
}
EXPORT_SYMBOL_GPL(unregister_pstore_device);
-/**
- * psblk_get_bdev() - open block device
- *
- * @holder: Exclusive holder identifier
- * @info: Information about bdev to fill in
- *
- * Return: pointer to block device on success and others on error.
- *
- * On success, the returned block_device has reference count of one.
- */
-static struct block_device *psblk_get_bdev(void *holder,
- struct bdev_info *info)
-{
- struct block_device *bdev = ERR_PTR(-ENODEV);
- fmode_t mode = FMODE_READ | FMODE_WRITE;
- sector_t nr_sects;
-
- lockdep_assert_held(&pstore_blk_lock);
-
- if (pstore_zone_info)
- return ERR_PTR(-EBUSY);
-
- if (!blkdev[0])
- return ERR_PTR(-ENODEV);
-
- if (holder)
- mode |= FMODE_EXCL;
- bdev = blkdev_get_by_path(blkdev, mode, holder);
- if (IS_ERR(bdev)) {
- dev_t devt;
-
- devt = name_to_dev_t(blkdev);
- if (devt == 0)
- return ERR_PTR(-ENODEV);
- bdev = blkdev_get_by_dev(devt, mode, holder);
- if (IS_ERR(bdev))
- return bdev;
- }
-
- nr_sects = part_nr_sects_read(bdev->bd_part);
- if (!nr_sects) {
- pr_err("not enough space for '%s'\n", blkdev);
- blkdev_put(bdev, mode);
- return ERR_PTR(-ENOSPC);
- }
-
- if (info) {
- info->devt = bdev->bd_dev;
- info->nr_sects = nr_sects;
- info->start_sect = get_start_sect(bdev);
- }
-
- return bdev;
-}
-
-static void psblk_put_bdev(struct block_device *bdev, void *holder)
-{
- fmode_t mode = FMODE_READ | FMODE_WRITE;
-
- lockdep_assert_held(&pstore_blk_lock);
-
- if (!bdev)
- return;
-
- if (holder)
- mode |= FMODE_EXCL;
- blkdev_put(bdev, mode);
-}
-
static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos)
{
struct block_device *bdev = psblk_bdev;
@@ -340,29 +265,39 @@ static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
return ret;
}
-static int __register_pstore_blk(void)
+static int __init pstore_blk_init(void)
{
char bdev_name[BDEVNAME_SIZE];
struct block_device *bdev;
struct pstore_device_info dev;
- struct bdev_info binfo;
- void *holder = blkdev;
int ret = -ENODEV;
-
- lockdep_assert_held(&pstore_blk_lock);
+ fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
+ sector_t nr_sects;
+
+ if (!best_effort || !blkdev[0])
+ return 0;
/* hold bdev exclusively */
- memset(&binfo, 0, sizeof(binfo));
- bdev = psblk_get_bdev(holder, &binfo);
+ bdev = blkdev_get_by_path(blkdev, mode, blkdev);
if (IS_ERR(bdev)) {
- pr_err("failed to open '%s'!\n", blkdev);
- return PTR_ERR(bdev);
+ dev_t devt;
+
+ devt = name_to_dev_t(blkdev);
+ if (devt == 0) {
+ pr_err("failed to open '%s'!\n", blkdev);
+ return -ENODEV;
+ }
+ bdev = blkdev_get_by_dev(devt, mode, blkdev);
+ if (IS_ERR(bdev)) {
+ pr_err("failed to open '%s'!\n", blkdev);
+ return PTR_ERR(bdev);
+ }
}
- /* only allow driver matching the @blkdev */
- if (!binfo.devt) {
- pr_debug("no major\n");
- ret = -ENODEV;
+ nr_sects = part_nr_sects_read(bdev->bd_part);
+ if (!nr_sects) {
+ pr_err("not enough space for '%s'\n", blkdev);
+ ret = -ENOSPC;
goto err_put_bdev;
}
@@ -370,11 +305,11 @@ static int __register_pstore_blk(void)
psblk_bdev = bdev;
memset(&dev, 0, sizeof(dev));
- dev.total_size = binfo.nr_sects << SECTOR_SHIFT;
+ dev.total_size = nr_sects << SECTOR_SHIFT;
dev.read = psblk_generic_blk_read;
dev.write = psblk_generic_blk_write;
- ret = __register_pstore_device(&dev);
+ ret = register_pstore_device(&dev);
if (ret)
goto err_put_bdev;
@@ -383,10 +318,22 @@ static int __register_pstore_blk(void)
return 0;
err_put_bdev:
+ blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
psblk_bdev = NULL;
- psblk_put_bdev(bdev, holder);
return ret;
}
+late_initcall(pstore_blk_init);
+
+static void __exit pstore_blk_exit(void)
+{
+ struct pstore_device_info dev = { .read = psblk_generic_blk_read };
+
+ if (!psblk_bdev)
+ return;
+ unregister_pstore_device(&dev);
+ blkdev_put(psblk_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+}
+module_exit(pstore_blk_exit);
/* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info)
@@ -402,33 +349,6 @@ int pstore_blk_get_config(struct pstore_blk_config *info)
}
EXPORT_SYMBOL_GPL(pstore_blk_get_config);
-static int __init pstore_blk_init(void)
-{
- int ret = 0;
-
- mutex_lock(&pstore_blk_lock);
- if (!pstore_zone_info && best_effort && blkdev[0])
- ret = __register_pstore_blk();
- mutex_unlock(&pstore_blk_lock);
-
- return ret;
-}
-late_initcall(pstore_blk_init);
-
-static void __exit pstore_blk_exit(void)
-{
- struct pstore_device_info dev = { };
-
- mutex_lock(&pstore_blk_lock);
- if (pstore_zone_info)
- dev.read = pstore_zone_info->read;
- __unregister_pstore_device(&dev);
- if (psblk_bdev)
- psblk_put_bdev(psblk_bdev, blkdev);
- mutex_unlock(&pstore_blk_lock);
-}
-module_exit(pstore_blk_exit);
-
MODULE_LICENSE("GPL");
MODULE_AUTHOR("WeiXiong Liao <liaoweixiong at allwinnertech.com>");
MODULE_AUTHOR("Kees Cook <keescook at chromium.org>");
--
2.28.0
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