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Message-Id: <20201016132047.3068029-9-hch@lst.de>
Date: Fri, 16 Oct 2020 15:20:46 +0200
From: Christoph Hellwig <hch@....de>
To: Kees Cook <keescook@...omium.org>,
Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Tony Luck <tony.luck@...el.com>,
WeiXiong Liao <liaoweixiong@...winnertech.com>
Cc: linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 8/9] pstore/blk: use the normal block device I/O path
Stop poking into block layer internals and just open the block device
file an use kernel_read and kernel_write on it. Note that this means
the transformation from name_to_dev_t can't be used anymore, and proper
block device file names must be used.
Signed-off-by: Christoph Hellwig <hch@....de>
---
fs/pstore/blk.c | 152 +++++++++++++------------------------
include/linux/pstore_blk.h | 2 +
init/main.c | 4 +
3 files changed, 57 insertions(+), 101 deletions(-)
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 0430b190a1df2a..bd4eadfc9bd795 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -8,15 +8,13 @@
#include <linux/kernel.h>
#include <linux/module.h>
-#include "../../block/blk.h"
#include <linux/blkdev.h>
#include <linux/string.h>
-#include <linux/of.h>
-#include <linux/of_address.h>
-#include <linux/platform_device.h>
#include <linux/pstore_blk.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/init_syscalls.h>
#include <linux/mount.h>
-#include <linux/uio.h>
static long kmsg_size = CONFIG_PSTORE_BLK_KMSG_SIZE;
module_param(kmsg_size, long, 0400);
@@ -88,7 +86,6 @@ MODULE_PARM_DESC(blkdev, "block device for pstore storage");
* during the register/unregister functions.
*/
static DEFINE_MUTEX(pstore_blk_lock);
-static struct block_device *psblk_bdev;
static struct pstore_zone_info *pstore_zone_info;
#define check_size(name, alignsize) ({ \
@@ -185,70 +182,20 @@ void unregister_pstore_device(const struct pstore_zone_ops *ops)
}
EXPORT_SYMBOL_GPL(unregister_pstore_device);
+static struct file *psblk_file;
+
static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos)
{
- struct block_device *bdev = psblk_bdev;
- struct file file;
- struct kiocb kiocb;
- struct iov_iter iter;
- struct kvec iov = {.iov_base = buf, .iov_len = bytes};
-
- if (!bdev)
- return -ENODEV;
-
- memset(&file, 0, sizeof(struct file));
- file.f_mapping = bdev->bd_inode->i_mapping;
- file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
- file.f_inode = bdev->bd_inode;
- file_ra_state_init(&file.f_ra, file.f_mapping);
-
- init_sync_kiocb(&kiocb, &file);
- kiocb.ki_pos = pos;
- iov_iter_kvec(&iter, READ, &iov, 1, bytes);
-
- return generic_file_read_iter(&kiocb, &iter);
+ return kernel_read(psblk_file, buf, bytes, &pos);
}
static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
loff_t pos)
{
- struct block_device *bdev = psblk_bdev;
- struct iov_iter iter;
- struct kiocb kiocb;
- struct file file;
- ssize_t ret;
- struct kvec iov = {.iov_base = (void *)buf, .iov_len = bytes};
-
- if (!bdev)
- return -ENODEV;
-
/* Console/Ftrace backend may handle buffer until flush dirty zones */
if (in_interrupt() || irqs_disabled())
return -EBUSY;
-
- memset(&file, 0, sizeof(struct file));
- file.f_mapping = bdev->bd_inode->i_mapping;
- file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
- file.f_inode = bdev->bd_inode;
-
- init_sync_kiocb(&kiocb, &file);
- kiocb.ki_pos = pos;
- iov_iter_kvec(&iter, WRITE, &iov, 1, bytes);
-
- inode_lock(bdev->bd_inode);
- ret = generic_write_checks(&kiocb, &iter);
- if (ret > 0)
- ret = generic_perform_write(&file, &iter, pos);
- inode_unlock(bdev->bd_inode);
-
- if (likely(ret > 0)) {
- const struct file_operations f_op = {.fsync = blkdev_fsync};
-
- file.f_op = &f_op;
- kiocb.ki_pos += ret;
- ret = generic_write_sync(&kiocb, ret);
- }
- return ret;
+ return kernel_write(psblk_file, buf, bytes, &pos);
}
static const struct pstore_zone_ops pstore_blk_zone_ops = {
@@ -257,68 +204,71 @@ static const struct pstore_zone_ops pstore_blk_zone_ops = {
.write = psblk_generic_blk_write,
};
-static int __init pstore_blk_init(void)
+static int __init __pstore_blk_init(const char *name)
{
- char bdev_name[BDEVNAME_SIZE];
- struct block_device *bdev;
- int ret = -ENODEV;
- fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
- sector_t nr_sects;
-
+ int ret = -EINVAL;
+
if (!best_effort || !blkdev[0])
return 0;
- /* hold bdev exclusively */
- bdev = blkdev_get_by_path(blkdev, mode, blkdev);
- if (IS_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);
- }
+ psblk_file = filp_open(name, O_RDWR | O_DSYNC | O_NOATIME | O_EXCL, 0);
+ if (IS_ERR(psblk_file)) {
+ ret = PTR_ERR(psblk_file);
+ pr_err("failed to open '%s': %d!\n", name, ret);
+ goto out;
}
-
- 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;
+ if (!S_ISBLK(file_inode(psblk_file)->i_mode)) {
+ pr_err("'%s' is not block device!\n", blkdev);
+ goto out_fput;
}
- /* psblk_bdev must be assigned before register to pstore/blk */
- psblk_bdev = bdev;
-
ret = register_pstore_device(&pstore_blk_zone_ops,
- nr_sects << SECTOR_SHIFT, 0);
+ file_inode(psblk_file)->i_bdev->bd_inode->i_size, 0);
if (ret)
- goto err_put_bdev;
+ goto out_fput;
- bdevname(bdev, bdev_name);
- pr_info("attached %s (no dedicated panic_write!)\n", bdev_name);
+ pr_info("using device '%s'\n", blkdev);
return 0;
-
-err_put_bdev:
- blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
- psblk_bdev = NULL;
+out_fput:
+ fput(psblk_file);
+out:
+ psblk_file = NULL;
return ret;
}
+
+#ifdef MODULE
+static int __init pstore_blk_init(void)
+{
+ return __pstore_blk_init(blkdev);
+}
late_initcall(pstore_blk_init);
static void __exit pstore_blk_exit(void)
{
- if (!psblk_bdev)
+ if (!psblk_file)
return;
unregister_pstore_device(&pstore_blk_zone_ops);
- blkdev_put(psblk_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+ fput(psblk_file);
}
module_exit(pstore_blk_exit);
+#else /* MODULE */
+/*
+ * During early boot the real root file system hasn't been mounted yet,
+ * and not device nodes are present yet. Use the same scheme to find
+ * the device that we use for mounting the root file system.
+ */
+void __init pstore_blk_early_init(void)
+{
+ const char devname[] = "/dev/pstore-blk";
+ dev_t dev = name_to_dev_t(blkdev);
+
+ if (!dev)
+ return;
+ init_unlink(devname);
+ init_mknod(devname, S_IFBLK | 0600, new_encode_dev(dev));
+ __pstore_blk_init(devname);
+}
+#endif /* MODULE */
/* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info)
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index 0abd412a6cb3e3..7c06b9d6740e2a 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -39,4 +39,6 @@ struct pstore_blk_config {
*/
int pstore_blk_get_config(struct pstore_blk_config *info);
+void __init pstore_blk_early_init(void);
+
#endif
diff --git a/init/main.c b/init/main.c
index 1af84337cb18d5..058cce64f70390 100644
--- a/init/main.c
+++ b/init/main.c
@@ -98,6 +98,7 @@
#include <linux/mem_encrypt.h>
#include <linux/kcsan.h>
#include <linux/init_syscalls.h>
+#include <linux/pstore_blk.h>
#include <asm/io.h>
#include <asm/bugs.h>
@@ -1524,6 +1525,9 @@ static noinline void __init kernel_init_freeable(void)
prepare_namespace();
}
+ if (IS_BUILTIN(CONFIG_PSTORE_BLK))
+ pstore_blk_early_init();
+
/*
* Ok, we have completed the initial bootup, and
* we're essentially up and running. Get rid of the
--
2.28.0
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