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path: root/fs/seq_file.c
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Diffstat (limited to 'fs/seq_file.c')
-rw-r--r--fs/seq_file.c160
1 files changed, 131 insertions, 29 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c
index f2bc3dfd0b8..3857b720cb1 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -8,8 +8,10 @@
#include <linux/fs.h>
#include <linux/export.h>
#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/cred.h>
+#include <linux/mm.h>
#include <asm/uaccess.h>
#include <asm/page.h>
@@ -30,6 +32,16 @@ static void seq_set_overflow(struct seq_file *m)
m->count = m->size;
}
+static void *seq_buf_alloc(unsigned long size)
+{
+ void *buf;
+
+ buf = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
+ if (!buf && size > PAGE_SIZE)
+ buf = vmalloc(size);
+ return buf;
+}
+
/**
* seq_open - initialize sequential file
* @file: file we initialize
@@ -96,7 +108,7 @@ static int traverse(struct seq_file *m, loff_t offset)
return 0;
}
if (!m->buf) {
- m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
+ m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
if (!m->buf)
return -ENOMEM;
}
@@ -135,8 +147,9 @@ static int traverse(struct seq_file *m, loff_t offset)
Eoverflow:
m->op->stop(m, p);
- kfree(m->buf);
- m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
+ kvfree(m->buf);
+ m->count = 0;
+ m->buf = seq_buf_alloc(m->size <<= 1);
return !m->buf ? -ENOMEM : -EAGAIN;
}
@@ -191,7 +204,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
/* grab buffer if we didn't have one */
if (!m->buf) {
- m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
+ m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
if (!m->buf)
goto Enomem;
}
@@ -231,11 +244,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
if (m->count < m->size)
goto Fill;
m->op->stop(m, p);
- kfree(m->buf);
- m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
+ kvfree(m->buf);
+ m->count = 0;
+ m->buf = seq_buf_alloc(m->size <<= 1);
if (!m->buf)
goto Enomem;
- m->count = 0;
m->version = 0;
pos = m->index;
p = m->op->start(m, &pos);
@@ -308,27 +321,29 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
mutex_lock(&m->lock);
m->version = file->f_version;
switch (whence) {
- case 1:
- offset += file->f_pos;
- case 0:
- if (offset < 0)
- break;
- retval = offset;
- if (offset != m->read_pos) {
- while ((retval=traverse(m, offset)) == -EAGAIN)
- ;
- if (retval) {
- /* with extreme prejudice... */
- file->f_pos = 0;
- m->read_pos = 0;
- m->version = 0;
- m->index = 0;
- m->count = 0;
- } else {
- m->read_pos = offset;
- retval = file->f_pos = offset;
- }
+ case SEEK_CUR:
+ offset += file->f_pos;
+ case SEEK_SET:
+ if (offset < 0)
+ break;
+ retval = offset;
+ if (offset != m->read_pos) {
+ while ((retval = traverse(m, offset)) == -EAGAIN)
+ ;
+ if (retval) {
+ /* with extreme prejudice... */
+ file->f_pos = 0;
+ m->read_pos = 0;
+ m->version = 0;
+ m->index = 0;
+ m->count = 0;
+ } else {
+ m->read_pos = offset;
+ retval = file->f_pos = offset;
}
+ } else {
+ file->f_pos = offset;
+ }
}
file->f_version = m->version;
mutex_unlock(&m->lock);
@@ -339,7 +354,7 @@ EXPORT_SYMBOL(seq_lseek);
/**
* seq_release - free the structures associated with sequential file.
* @file: file in question
- * @inode: file->f_path.dentry->d_inode
+ * @inode: its inode
*
* Frees the structures associated with sequential file; can be used
* as ->f_op->release() if you don't have private data to destroy.
@@ -347,7 +362,7 @@ EXPORT_SYMBOL(seq_lseek);
int seq_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
- kfree(m->buf);
+ kvfree(m->buf);
kfree(m);
return 0;
}
@@ -599,6 +614,24 @@ int single_open(struct file *file, int (*show)(struct seq_file *, void *),
}
EXPORT_SYMBOL(single_open);
+int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
+ void *data, size_t size)
+{
+ char *buf = seq_buf_alloc(size);
+ int ret;
+ if (!buf)
+ return -ENOMEM;
+ ret = single_open(file, show, data);
+ if (ret) {
+ kvfree(buf);
+ return ret;
+ }
+ ((struct seq_file *)file->private_data)->buf = buf;
+ ((struct seq_file *)file->private_data)->size = size;
+ return 0;
+}
+EXPORT_SYMBOL(single_open_size);
+
int single_release(struct inode *inode, struct file *file)
{
const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
@@ -746,6 +779,21 @@ int seq_write(struct seq_file *seq, const void *data, size_t len)
}
EXPORT_SYMBOL(seq_write);
+/**
+ * seq_pad - write padding spaces to buffer
+ * @m: seq_file identifying the buffer to which data should be written
+ * @c: the byte to append after padding if non-zero
+ */
+void seq_pad(struct seq_file *m, char c)
+{
+ int size = m->pad_until - m->count;
+ if (size > 0)
+ seq_printf(m, "%*s", size, "");
+ if (c)
+ seq_putc(m, c);
+}
+EXPORT_SYMBOL(seq_pad);
+
struct list_head *seq_list_start(struct list_head *head, loff_t pos)
{
struct list_head *lh;
@@ -903,3 +951,57 @@ struct hlist_node *seq_hlist_next_rcu(void *v,
return rcu_dereference(node->next);
}
EXPORT_SYMBOL(seq_hlist_next_rcu);
+
+/**
+ * seq_hlist_start_precpu - start an iteration of a percpu hlist array
+ * @head: pointer to percpu array of struct hlist_heads
+ * @cpu: pointer to cpu "cursor"
+ * @pos: start position of sequence
+ *
+ * Called at seq_file->op->start().
+ */
+struct hlist_node *
+seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
+{
+ struct hlist_node *node;
+
+ for_each_possible_cpu(*cpu) {
+ hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
+ if (pos-- == 0)
+ return node;
+ }
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(seq_hlist_start_percpu);
+
+/**
+ * seq_hlist_next_percpu - move to the next position of the percpu hlist array
+ * @v: pointer to current hlist_node
+ * @head: pointer to percpu array of struct hlist_heads
+ * @cpu: pointer to cpu "cursor"
+ * @pos: start position of sequence
+ *
+ * Called at seq_file->op->next().
+ */
+struct hlist_node *
+seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
+ int *cpu, loff_t *pos)
+{
+ struct hlist_node *node = v;
+
+ ++*pos;
+
+ if (node->next)
+ return node->next;
+
+ for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
+ *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
+ struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
+
+ if (!hlist_empty(bucket))
+ return bucket->first;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(seq_hlist_next_percpu);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 20:31:17 +0000