bitmap, irq: add smp_affinity_list interface to /proc/irq

Manually adjusting the smp_affinity for IRQ's becomes unwieldy when the
cpu count is large.

Setting smp affinity to cpus 256 to 263 would be:

	echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity

instead of:

	echo 256-263 > smp_affinity_list

Think about what it looks like for cpus around say, 4088 to 4095.

We already have many alternate "list" interfaces:

/sys/devices/system/cpu/cpuX/indexY/shared_cpu_list
/sys/devices/system/cpu/cpuX/topology/thread_siblings_list
/sys/devices/system/cpu/cpuX/topology/core_siblings_list
/sys/devices/system/node/nodeX/cpulist
/sys/devices/pci***/***/local_cpulist

Add a companion interface, smp_affinity_list to use cpu lists instead of
cpu maps.  This conforms to other companion interfaces where both a map
and a list interface exists.

This required adding a bitmap_parselist_user() function in a manner
similar to the bitmap_parse_user() function.

[akpm@linux-foundation.org: make __bitmap_parselist() static]
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 50 insertions, 4 deletions

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 834899f2500f..64e3df6ab1ef 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -19,7 +19,7 @@ static struct proc_dir_entry *root_irq_dir;
 
 #ifdef CONFIG_SMP
 
-static int irq_affinity_proc_show(struct seq_file *m, void *v)
+static int show_irq_affinity(int type, struct seq_file *m, void *v)
 {
         struct irq_desc *desc = irq_to_desc((long)m->private);
         const struct cpumask *mask = desc->irq_data.affinity;
@@ -28,7 +28,10 @@ static int irq_affinity_proc_show(struct seq_file *m, void *v)
         if (irqd_is_setaffinity_pending(&desc->irq_data))
                 mask = desc->pending_mask;
 #endif
-        seq_cpumask(m, mask);
+        if (type)
+                seq_cpumask_list(m, mask);
+        else
+                seq_cpumask(m, mask);
         seq_putc(m, '\n');
         return 0;
 }
@@ -59,7 +62,18 @@ static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
 #endif
 
 int no_irq_affinity;
-static ssize_t irq_affinity_proc_write(struct file *file,
+static int irq_affinity_proc_show(struct seq_file *m, void *v)
+{
+        return show_irq_affinity(0, m, v);
+}
+
+static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
+{
+        return show_irq_affinity(1, m, v);
+}
+
+
+static ssize_t write_irq_affinity(int type, struct file *file,
                 const char __user *buffer, size_t count, loff_t *pos)
 {
         unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
@@ -72,7 +86,10 @@ static ssize_t irq_affinity_proc_write(struct file *file,
         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
                 return -ENOMEM;
 
-        err = cpumask_parse_user(buffer, count, new_value);
+        if (type)
+                err = cpumask_parselist_user(buffer, count, new_value);
+        else
+                err = cpumask_parse_user(buffer, count, new_value);
         if (err)
                 goto free_cpumask;
 
@@ -100,11 +117,28 @@ free_cpumask:
         return err;
 }
 
+static ssize_t irq_affinity_proc_write(struct file *file,
+                const char __user *buffer, size_t count, loff_t *pos)
+{
+        return write_irq_affinity(0, file, buffer, count, pos);
+}
+
+static ssize_t irq_affinity_list_proc_write(struct file *file,
+                const char __user *buffer, size_t count, loff_t *pos)
+{
+        return write_irq_affinity(1, file, buffer, count, pos);
+}
+
 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
 {
         return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
 }
 
+static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, irq_affinity_list_proc_show, PDE(inode)->data);
+}
+
 static int irq_affinity_hint_proc_open(struct inode *inode, struct file *file)
 {
         return single_open(file, irq_affinity_hint_proc_show, PDE(inode)->data);
@@ -125,6 +159,14 @@ static const struct file_operations irq_affinity_hint_proc_fops = {
         .release        = single_release,
 };
 
+static const struct file_operations irq_affinity_list_proc_fops = {
+        .open           = irq_affinity_list_proc_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+        .write          = irq_affinity_list_proc_write,
+};
+
 static int default_affinity_show(struct seq_file *m, void *v)
 {
         seq_cpumask(m, irq_default_affinity);
@@ -289,6 +331,10 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
         proc_create_data("affinity_hint", 0400, desc->dir,
                          &irq_affinity_hint_proc_fops, (void *)(long)irq);
 
+        /* create /proc/irq/<irq>/smp_affinity_list */
+        proc_create_data("smp_affinity_list", 0600, desc->dir,
+                         &irq_affinity_list_proc_fops, (void *)(long)irq);
+
         proc_create_data("node", 0444, desc->dir,
                          &irq_node_proc_fops, (void *)(long)irq);
 #endif