[PATCH v7 18/18] pstore/blk: Introduce "best_effort" mode
From: Kees Cook <hidden>
Date: 2020-05-10 20:32:13
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), pstore filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Kees Cook, Linus Torvalds
In order to use arbitrary block devices as a pstore backend, provide a new module param named "best_effort", which will allow using any block device, even if it has not provided a panic_write callback. Signed-off-by: Kees Cook <redacted> --- fs/pstore/blk.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 0dea8ded2de2..ad46860d5a78 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c@@ -51,6 +51,10 @@ static long ftrace_size = -1; module_param(ftrace_size, long, 0400); MODULE_PARM_DESC(ftrace_size, "ftrace size in kbytes"); +static bool best_effort; +module_param(best_effort, bool, 0400); +MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require storage driver pstore support, default: off)"); + /* * blkdev - the block device to use for pstore storage *
@@ -376,7 +380,8 @@ static int __register_pstore_blk(struct pstore_blk_info *info) } /* only allow driver matching the @blkdev */ - if (!binfo.devt || MAJOR(binfo.devt) != info->major) { + if (!binfo.devt || (!best_effort && + MAJOR(binfo.devt) != info->major)) { pr_debug("invalid major %u (expect %u)\n", info->major, MAJOR(binfo.devt)); ret = -ENODEV;
@@ -479,6 +484,20 @@ int pstore_blk_get_config(struct pstore_blk_config *info) } EXPORT_SYMBOL_GPL(pstore_blk_get_config); +static int __init pstore_blk_init(void) +{ + struct pstore_blk_info info = { }; + int ret = 0; + + mutex_lock(&pstore_blk_lock); + if (!pstore_zone_info && best_effort && blkdev[0]) + ret = __register_pstore_blk(&info); + mutex_unlock(&pstore_blk_lock); + + return ret; +} +late_initcall(pstore_blk_init); + static void __exit pstore_blk_exit(void) { mutex_lock(&pstore_blk_lock);
--
2.20.1