[PATCH v3 5/5] pstore/blk: Include zone in pstore_device_info
Kees Cook
keescook at chromium.org
Wed Jun 16 09:40:43 PDT 2021
Information was redundant between struct pstore_zone_info and struct
pstore_device_info. Use struct pstore_zone_info, with member name "zone".
Additionally untangle the logic for the "best effort" block device
instance.
Signed-off-by: Kees Cook <keescook at chromium.org>
---
drivers/mtd/mtdpstore.c | 10 +--
fs/pstore/blk.c | 143 ++++++++++++++++++++-----------------
include/linux/pstore_blk.h | 27 +------
3 files changed, 87 insertions(+), 93 deletions(-)
diff --git a/drivers/mtd/mtdpstore.c b/drivers/mtd/mtdpstore.c
index a3ae8778f6a9..e13d42c0acb0 100644
--- a/drivers/mtd/mtdpstore.c
+++ b/drivers/mtd/mtdpstore.c
@@ -423,13 +423,13 @@ static void mtdpstore_notify_add(struct mtd_info *mtd)
longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize));
cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
- cxt->dev.total_size = mtd->size;
/* just support dmesg right now */
cxt->dev.flags = PSTORE_FLAGS_DMESG;
- cxt->dev.read = mtdpstore_read;
- cxt->dev.write = mtdpstore_write;
- cxt->dev.erase = mtdpstore_erase;
- cxt->dev.panic_write = mtdpstore_panic_write;
+ cxt->dev.zone.read = mtdpstore_read;
+ cxt->dev.zone.write = mtdpstore_write;
+ cxt->dev.zone.erase = mtdpstore_erase;
+ cxt->dev.zone.panic_write = mtdpstore_panic_write;
+ cxt->dev.zone.total_size = mtd->size;
ret = register_pstore_device(&cxt->dev);
if (ret) {
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index c373e0d73e6c..ccb82bcde7a8 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -70,7 +70,7 @@ MODULE_PARM_DESC(blkdev, "block device for pstore storage");
*/
static DEFINE_MUTEX(pstore_blk_lock);
static struct file *psblk_file;
-static struct pstore_zone_info *pstore_zone_info;
+static struct pstore_device_info *pstore_device_info;
#define check_size(name, alignsize) ({ \
long _##name_ = (name); \
@@ -91,7 +91,7 @@ static struct pstore_zone_info *pstore_zone_info;
_##name_ = 0; \
/* Synchronize module parameters with resuls. */ \
name = _##name_ / 1024; \
- pstore_zone_info->name = _##name_; \
+ dev->zone.name = _##name_; \
}
static int __register_pstore_device(struct pstore_device_info *dev)
@@ -104,50 +104,42 @@ static int __register_pstore_device(struct pstore_device_info *dev)
pr_err("NULL device info\n");
return -EINVAL;
}
- if (!dev->total_size) {
+ if (!dev->zone.total_size) {
pr_err("zero sized device\n");
return -EINVAL;
}
- if (!dev->read) {
+ if (!dev->zone.read) {
pr_err("no read handler for device\n");
return -EINVAL;
}
- if (!dev->write) {
+ if (!dev->zone.write) {
pr_err("no write handler for device\n");
return -EINVAL;
}
/* someone already registered before */
- if (pstore_zone_info)
+ if (pstore_device_info)
return -EBUSY;
- pstore_zone_info = kzalloc(sizeof(struct pstore_zone_info), GFP_KERNEL);
- if (!pstore_zone_info)
- return -ENOMEM;
-
/* zero means not limit on which backends to attempt to store. */
if (!dev->flags)
dev->flags = UINT_MAX;
+ /* Copy in module parameters. */
verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG);
verify_size(pmsg_size, 4096, dev->flags & PSTORE_FLAGS_PMSG);
verify_size(console_size, 4096, dev->flags & PSTORE_FLAGS_CONSOLE);
verify_size(ftrace_size, 4096, dev->flags & PSTORE_FLAGS_FTRACE);
+ dev->zone.max_reason = max_reason;
+
+ /* Initialize required zone ownership details. */
+ dev->zone.name = KBUILD_MODNAME;
+ dev->zone.owner = THIS_MODULE;
+
+ ret = register_pstore_zone(&dev->zone);
+ if (ret == 0)
+ pstore_device_info = dev;
- pstore_zone_info->total_size = dev->total_size;
- pstore_zone_info->max_reason = max_reason;
- pstore_zone_info->read = dev->read;
- pstore_zone_info->write = dev->write;
- pstore_zone_info->erase = dev->erase;
- pstore_zone_info->panic_write = dev->panic_write;
- pstore_zone_info->name = KBUILD_MODNAME;
- pstore_zone_info->owner = THIS_MODULE;
-
- ret = register_pstore_zone(pstore_zone_info);
- if (ret) {
- kfree(pstore_zone_info);
- pstore_zone_info = NULL;
- }
return ret;
}
/**
@@ -174,10 +166,9 @@ EXPORT_SYMBOL_GPL(register_pstore_device);
static void __unregister_pstore_device(struct pstore_device_info *dev)
{
lockdep_assert_held(&pstore_blk_lock);
- if (pstore_zone_info && pstore_zone_info->read == dev->read) {
- unregister_pstore_zone(pstore_zone_info);
- kfree(pstore_zone_info);
- pstore_zone_info = NULL;
+ if (pstore_device_info && pstore_device_info == dev) {
+ unregister_pstore_zone(&dev->zone);
+ pstore_device_info = NULL;
}
}
@@ -211,12 +202,9 @@ static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
/*
* This takes its configuration only from the module parameters now.
*/
-static int __register_pstore_blk(const char *devpath)
+static int __register_pstore_blk(struct pstore_device_info *dev,
+ const char *devpath)
{
- struct pstore_device_info dev = {
- .read = psblk_generic_blk_read,
- .write = psblk_generic_blk_write,
- };
struct inode *inode;
int ret = -ENODEV;
@@ -236,9 +224,9 @@ static int __register_pstore_blk(const char *devpath)
}
inode = I_BDEV(psblk_file->f_mapping->host)->bd_inode;
- dev.total_size = i_size_read(inode);
+ dev->zone.total_size = i_size_read(inode);
- ret = __register_pstore_device(&dev);
+ ret = __register_pstore_device(dev);
if (ret)
goto err_fput;
@@ -252,18 +240,6 @@ static int __register_pstore_blk(const char *devpath)
return ret;
}
-static void __unregister_pstore_blk(struct file *device)
-{
- struct pstore_device_info dev = { .read = psblk_generic_blk_read };
-
- lockdep_assert_held(&pstore_blk_lock);
- if (psblk_file && psblk_file == device) {
- __unregister_pstore_device(&dev);
- fput(psblk_file);
- psblk_file = NULL;
- }
-}
-
/* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info)
{
@@ -308,18 +284,63 @@ static inline const char *early_boot_devpath(const char *initial_devname)
}
#endif
+static int __init __best_effort_init(void)
+{
+ struct pstore_device_info *best_effort_dev;
+ int ret;
+
+ /* No best-effort mode requested. */
+ if (!best_effort)
+ return 0;
+
+ /* Reject an empty blkdev. */
+ if (!blkdev[0]) {
+ pr_err("blkdev empty with best_effort=Y\n");
+ return -EINVAL;
+ }
+
+ best_effort_dev = kzalloc(sizeof(*best_effort_dev), GFP_KERNEL);
+ if (!best_effort)
+ return -ENOMEM;
+
+ best_effort_dev->zone.read = psblk_generic_blk_read;
+ best_effort_dev->zone.write = psblk_generic_blk_write;
+
+ ret = __register_pstore_blk(best_effort_dev,
+ early_boot_devpath(blkdev));
+ if (ret)
+ kfree(best_effort_dev);
+ else
+ pr_info("attached %s (%zu) (no dedicated panic_write!)\n",
+ blkdev, best_effort_dev->zone.total_size);
+
+ return ret;
+}
+
+static void __exit __best_effort_exit(void)
+{
+ /*
+ * Currently, the only user of psblk_file is best_effort, so
+ * we can assume that pstore_device_info is associated with it.
+ * Once there are "real" blk devices, there will need to be a
+ * dedicated pstore_blk_info, etc.
+ */
+ if (psblk_file) {
+ struct pstore_device_info *dev = pstore_device_info;
+
+ __unregister_pstore_device(dev);
+ kfree(dev);
+ fput(psblk_file);
+ psblk_file = NULL;
+ }
+}
+
static int __init pstore_blk_init(void)
{
- int ret = 0;
+ int ret;
mutex_lock(&pstore_blk_lock);
- if (!pstore_zone_info && best_effort && blkdev[0]) {
- ret = __register_pstore_blk(early_boot_devpath(blkdev));
- if (ret == 0 && pstore_zone_info)
- pr_info("attached %s:%s (%zu) (no dedicated panic_write!)\n",
- pstore_zone_info->name, blkdev,
- pstore_zone_info->total_size);
- }
+ ret = __best_effort_init();
mutex_unlock(&pstore_blk_lock);
return ret;
@@ -329,15 +350,9 @@ late_initcall(pstore_blk_init);
static void __exit pstore_blk_exit(void)
{
mutex_lock(&pstore_blk_lock);
- if (psblk_file)
- __unregister_pstore_blk(psblk_file);
- else {
- struct pstore_device_info dev = { };
-
- if (pstore_zone_info)
- dev.read = pstore_zone_info->read;
- __unregister_pstore_device(&dev);
- }
+ __best_effort_exit();
+ /* If we've been asked to unload, unregister any remaining device. */
+ __unregister_pstore_device(pstore_device_info);
mutex_unlock(&pstore_blk_lock);
}
module_exit(pstore_blk_exit);
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index 99564f93d774..924ca07aafbd 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -10,36 +10,15 @@
/**
* struct pstore_device_info - back-end pstore/blk driver structure.
*
- * @total_size: The total size in bytes pstore/blk can use. It must be greater
- * than 4096 and be multiple of 4096.
* @flags: Refer to macro starting with PSTORE_FLAGS defined in
* linux/pstore.h. It means what front-ends this device support.
* Zero means all backends for compatible.
- * @read: The general read operation. Both of the function parameters
- * @size and @offset are relative value to bock device (not the
- * whole disk).
- * On success, the number of bytes should be returned, others
- * means error.
- * @write: The same as @read, but the following error number:
- * -EBUSY means try to write again later.
- * -ENOMSG means to try next zone.
- * @erase: The general erase operation for device with special removing
- * job. Both of the function parameters @size and @offset are
- * relative value to storage.
- * Return 0 on success and others on failure.
- * @panic_write:The write operation only used for panic case. It's optional
- * if you do not care panic log. The parameters are relative
- * value to storage.
- * On success, the number of bytes should be returned, others
- * excluding -ENOMSG mean error. -ENOMSG means to try next zone.
+ * @zone: The struct pstore_zone_info details.
+ *
*/
struct pstore_device_info {
- unsigned long total_size;
unsigned int flags;
- pstore_zone_read_op read;
- pstore_zone_write_op write;
- pstore_zone_erase_op erase;
- pstore_zone_write_op panic_write;
+ struct pstore_zone_info zone;
};
int register_pstore_device(struct pstore_device_info *dev);
--
2.25.1
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