6.7-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit 7d4b5d7a37bdd63a5a3371b988744b060d5bb86f upstream.
In preparation for subsequent changes, introduce a specialized variant of async_schedule_dev() that will not invoke the argument function synchronously when it cannot be scheduled for asynchronous execution.
The new function, async_schedule_dev_nocall(), will be used for fixing possible deadlocks in the system-wide power management core code.
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Reviewed-by: Stanislaw Gruszka stanislaw.gruszka@linux.intel.com for the series. Tested-by: Youngmin Nam youngmin.nam@samsung.com Reviewed-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/async.h | 2 ++ kernel/async.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+)
--- a/include/linux/async.h +++ b/include/linux/async.h @@ -90,6 +90,8 @@ async_schedule_dev(async_func_t func, st return async_schedule_node(func, dev, dev_to_node(dev)); }
+bool async_schedule_dev_nocall(async_func_t func, struct device *dev); + /** * async_schedule_dev_domain - A device specific version of async_schedule_domain * @func: function to execute asynchronously --- a/kernel/async.c +++ b/kernel/async.c @@ -244,6 +244,35 @@ async_cookie_t async_schedule_node(async EXPORT_SYMBOL_GPL(async_schedule_node);
/** + * async_schedule_dev_nocall - A simplified variant of async_schedule_dev() + * @func: function to execute asynchronously + * @dev: device argument to be passed to function + * + * @dev is used as both the argument for the function and to provide NUMA + * context for where to run the function. + * + * If the asynchronous execution of @func is scheduled successfully, return + * true. Otherwise, do nothing and return false, unlike async_schedule_dev() + * that will run the function synchronously then. + */ +bool async_schedule_dev_nocall(async_func_t func, struct device *dev) +{ + struct async_entry *entry; + + entry = kzalloc(sizeof(struct async_entry), GFP_KERNEL); + + /* Give up if there is no memory or too much work. */ + if (!entry || atomic_read(&entry_count) > MAX_WORK) { + kfree(entry); + return false; + } + + __async_schedule_node_domain(func, dev, dev_to_node(dev), + &async_dfl_domain, entry); + return true; +} + +/** * async_synchronize_full - synchronize all asynchronous function calls * * This function waits until all asynchronous function calls have been done.