[RFC] [PATCH 2/2] Multi-threaded execution of ACPI control methods (continued)

[Peter Wainwright <prw@xxxxxxxxxxxxxxxxxxxxx>]

This patch enables the maximum size of the ACPI thread pool to be
configured by a /proc filesystem entry.

This limit is imposed in case a rogue BIOS DSDT tries to create too
many threads.

Peter

Signed-off-by: Peter Wainwright <prw@xxxxxxxxxxxxxxxxxxxxx>



diff -u -r linux-2.6.16.11-prw2-old/drivers/acpi/osl.c linux-2.6.16.11-prw2/drivers/acpi/osl.c
--- linux-2.6.16.11-prw2-old/drivers/acpi/osl.c	2006-05-03 21:14:05.000000000 +0100
+++ linux-2.6.16.11-prw2/drivers/acpi/osl.c	2006-05-03 21:16:30.000000000 +0100
@@ -47,6 +47,8 @@
 #include <linux/efi.h>
 
 #include <linux/kthread.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 
 #define _COMPONENT		ACPI_OS_SERVICES
 ACPI_MODULE_NAME("osl")
@@ -109,6 +111,66 @@
 	struct list_head list;
 };
 
+static int acpi_osl_pool_size_read(struct seq_file *seq, void *offset)
+{
+	struct list_head *l;
+
+	ACPI_FUNCTION_TRACE("acpi_osl_pool_size_read");
+
+	seq_printf(seq, "max_pool_size=%d\n", max_pool_size);
+	seq_printf(seq, "current_pool_size=%d\n", current_pool_size);
+	/* FIXME: Need lock? */
+	list_for_each(l, &thread_pool) {
+		struct thread_pool_entry *e = list_entry(l, struct thread_pool_entry, list);
+		seq_printf(seq, "entry=(%p,%d,%p,%p,%lu)\n",
+			   e->thread, e->active, e->function, e->context, e->jiffies);
+	}
+	return_VALUE(0);
+}
+
+static int acpi_osl_pool_size_open_fs(struct inode *inode, struct file *file)
+{
+	return single_open(file, acpi_osl_pool_size_read, PDE(inode)->data);
+}
+
+static ssize_t
+acpi_osl_pool_size_write(struct file *file,
+			   const char __user * buffer,
+			   size_t count, loff_t * ppos)
+{
+	char *size_string;
+
+	ACPI_FUNCTION_TRACE("acpi_osl_pool_size_write");
+
+	size_string = kmalloc(4096, GFP_KERNEL);
+	if (!size_string)
+		return_VALUE(-ENOMEM);
+
+	memset(size_string, 0, 4096);
+
+	if (copy_from_user(size_string, buffer, count)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data\n"));
+		count = -EFAULT;
+		goto end;
+	}
+
+	size_string[count] = '\0';
+	max_pool_size = simple_strtol(size_string, NULL, 10);
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Pool_Size now %d\n", max_pool_size));
+
+end:
+	kfree(size_string);
+	return_VALUE(count);
+}
+
+static struct file_operations acpi_osl_pool_size_ops = {
+	.open = acpi_osl_pool_size_open_fs,
+	.read = seq_read,
+	.write = acpi_osl_pool_size_write,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
 /* This is based on the workqueue worker_thread */
 static int acpi_os_execute_worker(void *context)
 {
@@ -247,9 +309,14 @@
 
 /*
  * Enable reaping of unused threads.
+ * Enable pool size modification by proc filesystem entry.
  */
 acpi_status acpi_os_initialize2(void)
 {
+	struct proc_dir_entry *entry;
+	entry = create_proc_entry("pool_size", S_IRUSR|S_IWUSR, acpi_root_dir);
+	if (entry)
+		entry->proc_fops = &acpi_osl_pool_size_ops;
 	INIT_WORK(&acpi_reap_task, acpi_reap_threads, NULL);
 	init_timer(&acpi_reap_timer);
 	return AE_OK;

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