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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cache.h>#include <linux/fs.h>#include <linux/export.h>#include <linux/hex.h>#include <linux/seq_file.h>#include <linux/vmalloc.h>#include <linux/slab.h>#include <linux/cred.h>#include <linux/mm.h>#include <linux/printk.h>#include <linux/string_helpers.h>#include <linux/uio.h>
#include <linux/uaccess.h>#include <asm/page.h>
static struct kmem_cache *seq_file_cache __ro_after_init;
static void seq_set_overflow(struct seq_file *m){ m->count = m->size;}
static void *seq_buf_alloc(unsigned long size){ if (unlikely(size > MAX_RW_COUNT)) return NULL;
return kvmalloc(size, GFP_KERNEL_ACCOUNT);}
/** * seq_open - initialize sequential file * @file: file we initialize * @op: method table describing the sequence * * seq_open() sets @file, associating it with a sequence described * by @op. @op->start() sets the iterator up and returns the first * element of sequence. @op->stop() shuts it down. @op->next() * returns the next element of sequence. @op->show() prints element * into the buffer. In case of error ->start() and ->next() return * ERR_PTR(error). In the end of sequence they return %NULL. ->show() * returns 0 in case of success and negative number in case of error. * Returning SEQ_SKIP means "discard this element and move on". * Note: seq_open() will allocate a struct seq_file and store its * pointer in @file->private_data. This pointer should not be modified. */int seq_open(struct file *file, const struct seq_operations *op){ struct seq_file *p;
WARN_ON(file->private_data);
p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL); if (!p) return -ENOMEM;
file->private_data = p;
mutex_init(&p->lock); p->op = op;
// No refcounting: the lifetime of 'p' is constrained // to the lifetime of the file. p->file = file;
/* * seq_files support lseek() and pread(). They do not implement * write() at all, but we clear FMODE_PWRITE here for historical * reasons. * * If a client of seq_files a) implements file.write() and b) wishes to * support pwrite() then that client will need to implement its own * file.open() which calls seq_open() and then sets FMODE_PWRITE. */ file->f_mode &= ~FMODE_PWRITE; return 0;}EXPORT_SYMBOL(seq_open);
static int traverse(struct seq_file *m, loff_t offset){ loff_t pos = 0; int error = 0; void *p;
m->index = 0; m->count = m->from = 0; if (!offset) return 0;
if (!m->buf) { m->buf = seq_buf_alloc(m->size = PAGE_SIZE); if (!m->buf) return -ENOMEM; } p = m->op->start(m, &m->index); while (p) { error = PTR_ERR(p); if (IS_ERR(p)) break; error = m->op->show(m, p); if (error < 0) break; if (unlikely(error)) { error = 0; m->count = 0; } if (seq_has_overflowed(m)) goto Eoverflow; p = m->op->next(m, p, &m->index); if (pos + m->count > offset) { m->from = offset - pos; m->count -= m->from; break; } pos += m->count; m->count = 0; if (pos == offset) break; } m->op->stop(m, p); return error;
Eoverflow: m->op->stop(m, p); kvfree(m->buf); m->count = 0; m->buf = seq_buf_alloc(m->size <<= 1); return !m->buf ? -ENOMEM : -EAGAIN;}
/** * seq_read - ->read() method for sequential files. * @file: the file to read from * @buf: the buffer to read to * @size: the maximum number of bytes to read * @ppos: the current position in the file * * Ready-made ->f_op->read() */ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos){ struct iovec iov = { .iov_base = buf, .iov_len = size}; struct kiocb kiocb; struct iov_iter iter; ssize_t ret;
init_sync_kiocb(&kiocb, file); iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
kiocb.ki_pos = *ppos; ret = seq_read_iter(&kiocb, &iter); *ppos = kiocb.ki_pos; return ret;}EXPORT_SYMBOL(seq_read);
/* * Ready-made ->f_op->read_iter() */ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter){ struct seq_file *m = iocb->ki_filp->private_data; size_t copied = 0; size_t n; void *p; int err = 0;
if (!iov_iter_count(iter)) return 0;
mutex_lock(&m->lock);
/* * if request is to read from zero offset, reset iterator to first * record as it might have been already advanced by previous requests */ if (iocb->ki_pos == 0) { m->index = 0; m->count = 0; }
/* Don't assume ki_pos is where we left it */ if (unlikely(iocb->ki_pos != m->read_pos)) { while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN) ; if (err) { /* With prejudice... */ m->read_pos = 0; m->index = 0; m->count = 0; goto Done; } else { m->read_pos = iocb->ki_pos; } }
/* grab buffer if we didn't have one */ if (!m->buf) { m->buf = seq_buf_alloc(m->size = PAGE_SIZE); if (!m->buf) goto Enomem; } // something left in the buffer - copy it out first if (m->count) { n = copy_to_iter(m->buf + m->from, m->count, iter); m->count -= n; m->from += n; copied += n; if (m->count) // hadn't managed to copy everything goto Done; } // get a non-empty record in the buffer m->from = 0; p = m->op->start(m, &m->index); while (1) { err = PTR_ERR(p); if (!p || IS_ERR(p)) // EOF or an error break; err = m->op->show(m, p); if (err < 0) // hard error break; if (unlikely(err)) // ->show() says "skip it" m->count = 0; if (unlikely(!m->count)) { // empty record p = m->op->next(m, p, &m->index); continue; } if (!seq_has_overflowed(m)) // got it goto Fill; // need a bigger buffer m->op->stop(m, p); kvfree(m->buf); m->count = 0; m->buf = seq_buf_alloc(m->size <<= 1); if (!m->buf) goto Enomem; p = m->op->start(m, &m->index); } // EOF or an error m->op->stop(m, p); m->count = 0; goto Done;Fill: // one non-empty record is in the buffer; if they want more, // try to fit more in, but in any case we need to advance // the iterator once for every record shown. while (1) { size_t offs = m->count; loff_t pos = m->index;
p = m->op->next(m, p, &m->index); if (pos == m->index) { pr_info_ratelimited("buggy .next function %ps did not update position index\n", m->op->next); m->index++; } if (!p || IS_ERR(p)) // no next record for us break; if (m->count >= iov_iter_count(iter)) break; err = m->op->show(m, p); if (err > 0) { // ->show() says "skip it" m->count = offs; } else if (err || seq_has_overflowed(m)) { m->count = offs; break; } } m->op->stop(m, p); n = copy_to_iter(m->buf, m->count, iter); copied += n; m->count -= n; m->from = n;Done: if (unlikely(!copied)) { copied = m->count ? -EFAULT : err; } else { iocb->ki_pos += copied; m->read_pos += copied; } mutex_unlock(&m->lock); return copied;Enomem: err = -ENOMEM; goto Done;}EXPORT_SYMBOL(seq_read_iter);
/** * seq_lseek - ->llseek() method for sequential files. * @file: the file in question * @offset: new position * @whence: 0 for absolute, 1 for relative position * * Ready-made ->f_op->llseek() */loff_t seq_lseek(struct file *file, loff_t offset, int whence){ struct seq_file *m = file->private_data; loff_t retval = -EINVAL;
mutex_lock(&m->lock); switch (whence) { case SEEK_CUR: offset += file->f_pos; fallthrough; 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->index = 0; m->count = 0; } else { m->read_pos = offset; retval = file->f_pos = offset; } } else { file->f_pos = offset; } } mutex_unlock(&m->lock); return retval;}EXPORT_SYMBOL(seq_lseek);
/** * seq_release - free the structures associated with sequential file. * @inode: its inode * @file: file in question * * Frees the structures associated with sequential file; can be used * as ->f_op->release() if you don't have private data to destroy. */int seq_release(struct inode *inode, struct file *file){ struct seq_file *m = file->private_data; kvfree(m->buf); kmem_cache_free(seq_file_cache, m); return 0;}EXPORT_SYMBOL(seq_release);
/** * seq_escape_mem - print data into buffer, escaping some characters * @m: target buffer * @src: source buffer * @len: size of source buffer * @flags: flags to pass to string_escape_mem() * @esc: set of characters that need escaping * * Puts data into buffer, replacing each occurrence of character from * given class (defined by @flags and @esc) with printable escaped sequence. * * Use seq_has_overflowed() to check for errors. */void seq_escape_mem(struct seq_file *m, const char *src, size_t len, unsigned int flags, const char *esc){ char *buf; size_t size = seq_get_buf(m, &buf); int ret;
ret = string_escape_mem(src, len, buf, size, flags, esc); seq_commit(m, ret < size ? ret : -1);}EXPORT_SYMBOL(seq_escape_mem);
void seq_vprintf(struct seq_file *m, const char *f, va_list args){ int len;
if (m->count < m->size) { len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); if (m->count + len < m->size) { m->count += len; return; } } seq_set_overflow(m);}EXPORT_SYMBOL(seq_vprintf);
void seq_printf(struct seq_file *m, const char *f, ...){ va_list args;
va_start(args, f); seq_vprintf(m, f, args); va_end(args);}EXPORT_SYMBOL(seq_printf);
#ifdef CONFIG_BINARY_PRINTFvoid seq_bprintf(struct seq_file *m, const char *f, const u32 *binary){ int len;
if (m->count < m->size) { len = bstr_printf(m->buf + m->count, m->size - m->count, f, binary); if (m->count + len < m->size) { m->count += len; return; } } seq_set_overflow(m);}EXPORT_SYMBOL(seq_bprintf);#endif /* CONFIG_BINARY_PRINTF */
/** * mangle_path - mangle and copy path to buffer beginning * @s: buffer start * @p: beginning of path in above buffer * @esc: set of characters that need escaping * * Copy the path from @p to @s, replacing each occurrence of character from * @esc with usual octal escape. * Returns pointer past last written character in @s, or NULL in case of * failure. */char *mangle_path(char *s, const char *p, const char *esc){ while (s <= p) { char c = *p++; if (!c) { return s; } else if (!strchr(esc, c)) { *s++ = c; } else if (s + 4 > p) { break; } else { *s++ = '\\'; *s++ = '0' + ((c & 0300) >> 6); *s++ = '0' + ((c & 070) >> 3); *s++ = '0' + (c & 07); } } return NULL;}EXPORT_SYMBOL(mangle_path);
/** * seq_path - seq_file interface to print a pathname * @m: the seq_file handle * @path: the struct path to print * @esc: set of characters to escape in the output * * return the absolute path of 'path', as represented by the * dentry / mnt pair in the path parameter. */int seq_path(struct seq_file *m, const struct path *path, const char *esc){ char *buf; size_t size = seq_get_buf(m, &buf); int res = -1;
if (size) { char *p = d_path(path, buf, size); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; } } seq_commit(m, res);
return res;}EXPORT_SYMBOL(seq_path);
/** * seq_file_path - seq_file interface to print a pathname of a file * @m: the seq_file handle * @file: the struct file to print * @esc: set of characters to escape in the output * * return the absolute path to the file. */int seq_file_path(struct seq_file *m, struct file *file, const char *esc){ return seq_path(m, &file->f_path, esc);}EXPORT_SYMBOL(seq_file_path);
/* * Same as seq_path, but relative to supplied root. */int seq_path_root(struct seq_file *m, const struct path *path, const struct path *root, const char *esc){ char *buf; size_t size = seq_get_buf(m, &buf); int res = -ENAMETOOLONG;
if (size) { char *p;
p = __d_path(path, root, buf, size); if (!p) return SEQ_SKIP; res = PTR_ERR(p); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; else res = -ENAMETOOLONG; } } seq_commit(m, res);
return res < 0 && res != -ENAMETOOLONG ? res : 0;}
/* * returns the path of the 'dentry' from the root of its filesystem. */int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc){ char *buf; size_t size = seq_get_buf(m, &buf); int res = -1;
if (size) { char *p = dentry_path(dentry, buf, size); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; } } seq_commit(m, res);
return res;}EXPORT_SYMBOL(seq_dentry);
void *single_start(struct seq_file *p, loff_t *pos){ return *pos ? NULL : SEQ_START_TOKEN;}
static void *single_next(struct seq_file *p, void *v, loff_t *pos){ ++*pos; return NULL;}
static void single_stop(struct seq_file *p, void *v){}
int single_open(struct file *file, int (*show)(struct seq_file *, void *), void *data){ struct seq_operations *op = kmalloc_obj(*op, GFP_KERNEL_ACCOUNT); int res = -ENOMEM;
if (op) { op->start = single_start; op->next = single_next; op->stop = single_stop; op->show = show; res = seq_open(file, op); if (!res) ((struct seq_file *)file->private_data)->private = data; else kfree(op); } return res;}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; int res = seq_release(inode, file); kfree(op); return res;}EXPORT_SYMBOL(single_release);
int seq_release_private(struct inode *inode, struct file *file){ struct seq_file *seq = file->private_data;
kfree(seq->private); seq->private = NULL; return seq_release(inode, file);}EXPORT_SYMBOL(seq_release_private);
void *__seq_open_private(struct file *f, const struct seq_operations *ops, int psize){ int rc; void *private; struct seq_file *seq;
private = kzalloc(psize, GFP_KERNEL_ACCOUNT); if (private == NULL) goto out;
rc = seq_open(f, ops); if (rc < 0) goto out_free;
seq = f->private_data; seq->private = private; return private;
out_free: kfree(private);out: return NULL;}EXPORT_SYMBOL(__seq_open_private);
int seq_open_private(struct file *filp, const struct seq_operations *ops, int psize){ return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;}EXPORT_SYMBOL(seq_open_private);
void seq_putc(struct seq_file *m, char c){ if (m->count >= m->size) return;
m->buf[m->count++] = c;}EXPORT_SYMBOL(seq_putc);
void __seq_puts(struct seq_file *m, const char *s){ seq_write(m, s, strlen(s));}EXPORT_SYMBOL(__seq_puts);
/** * seq_put_decimal_ull_width - A helper routine for putting decimal numbers * without rich format of printf(). * only 'unsigned long long' is supported. * @m: seq_file identifying the buffer to which data should be written * @delimiter: a string which is printed before the number * @num: the number * @width: a minimum field width * * This routine will put strlen(delimiter) + number into seq_filed. * This routine is very quick when you show lots of numbers. * In usual cases, it will be better to use seq_printf(). It's easier to read. */void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter, unsigned long long num, unsigned int width){ int len;
if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */ goto overflow;
if (delimiter && delimiter[0]) { if (delimiter[1] == 0) seq_putc(m, delimiter[0]); else seq_puts(m, delimiter); }
if (!width) width = 1;
if (m->count + width >= m->size) goto overflow;
len = num_to_str(m->buf + m->count, m->size - m->count, num, width); if (!len) goto overflow;
m->count += len; return;
overflow: seq_set_overflow(m);}
void seq_put_decimal_ull(struct seq_file *m, const char *delimiter, unsigned long long num){ return seq_put_decimal_ull_width(m, delimiter, num, 0);}EXPORT_SYMBOL(seq_put_decimal_ull);
/** * seq_put_hex_ll - put a number in hexadecimal notation * @m: seq_file identifying the buffer to which data should be written * @delimiter: a string which is printed before the number * @v: the number * @width: a minimum field width * * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v) * * This routine is very quick when you show lots of numbers. * In usual cases, it will be better to use seq_printf(). It's easier to read. */void seq_put_hex_ll(struct seq_file *m, const char *delimiter, unsigned long long v, unsigned int width){ unsigned int len; int i;
if (delimiter && delimiter[0]) { if (delimiter[1] == 0) seq_putc(m, delimiter[0]); else seq_puts(m, delimiter); }
/* If x is 0, the result of __builtin_clzll is undefined */ if (v == 0) len = 1; else len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
if (len < width) len = width;
if (m->count + len > m->size) { seq_set_overflow(m); return; }
for (i = len - 1; i >= 0; i--) { m->buf[m->count + i] = hex_asc[0xf & v]; v = v >> 4; } m->count += len;}
void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num){ int len;
if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */ goto overflow;
if (delimiter && delimiter[0]) { if (delimiter[1] == 0) seq_putc(m, delimiter[0]); else seq_puts(m, delimiter); }
if (m->count + 2 >= m->size) goto overflow;
if (num < 0) { m->buf[m->count++] = '-'; num = -num; }
if (num < 10) { m->buf[m->count++] = num + '0'; return; }
len = num_to_str(m->buf + m->count, m->size - m->count, num, 0); if (!len) goto overflow;
m->count += len; return;
overflow: seq_set_overflow(m);}EXPORT_SYMBOL(seq_put_decimal_ll);
/** * seq_write - write arbitrary data to buffer * @seq: seq_file identifying the buffer to which data should be written * @data: data address * @len: number of bytes * * Return 0 on success, non-zero otherwise. */int seq_write(struct seq_file *seq, const void *data, size_t len){ if (seq->count + len < seq->size) { memcpy(seq->buf + seq->count, data, len); seq->count += len; return 0; } seq_set_overflow(seq); return -1;}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) { if (size + m->count > m->size) { seq_set_overflow(m); return; } memset(m->buf + m->count, ' ', size); m->count += size; } if (c) seq_putc(m, c);}EXPORT_SYMBOL(seq_pad);
/* A complete analogue of print_hex_dump() */void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type, int rowsize, int groupsize, const void *buf, size_t len, bool ascii){ const u8 *ptr = buf; int i, linelen, remaining = len; char *buffer; size_t size; int ret;
if (rowsize != 16 && rowsize != 32) rowsize = 16;
for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) { linelen = min(remaining, rowsize); remaining -= rowsize;
switch (prefix_type) { case DUMP_PREFIX_ADDRESS: seq_printf(m, "%s%p: ", prefix_str, ptr + i); break; case DUMP_PREFIX_OFFSET: seq_printf(m, "%s%.8x: ", prefix_str, i); break; default: seq_printf(m, "%s", prefix_str); break; }
size = seq_get_buf(m, &buffer); ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, buffer, size, ascii); seq_commit(m, ret < size ? ret : -1);
seq_putc(m, '\n'); }}EXPORT_SYMBOL(seq_hex_dump);
struct list_head *seq_list_start(struct list_head *head, loff_t pos){ struct list_head *lh;
list_for_each(lh, head) if (pos-- == 0) return lh;
return NULL;}EXPORT_SYMBOL(seq_list_start);
struct list_head *seq_list_start_head(struct list_head *head, loff_t pos){ if (!pos) return head;
return seq_list_start(head, pos - 1);}EXPORT_SYMBOL(seq_list_start_head);
struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos){ struct list_head *lh;
lh = ((struct list_head *)v)->next; ++*ppos; return lh == head ? NULL : lh;}EXPORT_SYMBOL(seq_list_next);
struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos){ struct list_head *lh;
list_for_each_rcu(lh, head) if (pos-- == 0) return lh;
return NULL;}EXPORT_SYMBOL(seq_list_start_rcu);
struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos){ if (!pos) return head;
return seq_list_start_rcu(head, pos - 1);}EXPORT_SYMBOL(seq_list_start_head_rcu);
struct list_head *seq_list_next_rcu(void *v, struct list_head *head, loff_t *ppos){ struct list_head *lh;
lh = list_next_rcu((struct list_head *)v); ++*ppos; return lh == head ? NULL : lh;}EXPORT_SYMBOL(seq_list_next_rcu);
/** * seq_hlist_start - start an iteration of a hlist * @head: the head of the hlist * @pos: the start position of the sequence * * Called at seq_file->op->start(). */struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos){ struct hlist_node *node;
hlist_for_each(node, head) if (pos-- == 0) return node; return NULL;}EXPORT_SYMBOL(seq_hlist_start);
/** * seq_hlist_start_head - start an iteration of a hlist * @head: the head of the hlist * @pos: the start position of the sequence * * Called at seq_file->op->start(). Call this function if you want to * print a header at the top of the output. */struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos){ if (!pos) return SEQ_START_TOKEN;
return seq_hlist_start(head, pos - 1);}EXPORT_SYMBOL(seq_hlist_start_head);
/** * seq_hlist_next - move to the next position of the hlist * @v: the current iterator * @head: the head of the hlist * @ppos: the current position * * Called at seq_file->op->next(). */struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, loff_t *ppos){ struct hlist_node *node = v;
++*ppos; if (v == SEQ_START_TOKEN) return head->first; else return node->next;}EXPORT_SYMBOL(seq_hlist_next);
/** * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU * @head: the head of the hlist * @pos: the start position of the sequence * * Called at seq_file->op->start(). * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as hlist_add_head_rcu() * as long as the traversal is guarded by rcu_read_lock(). */struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, loff_t pos){ struct hlist_node *node;
__hlist_for_each_rcu(node, head) if (pos-- == 0) return node; return NULL;}EXPORT_SYMBOL(seq_hlist_start_rcu);
/** * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU * @head: the head of the hlist * @pos: the start position of the sequence * * Called at seq_file->op->start(). Call this function if you want to * print a header at the top of the output. * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as hlist_add_head_rcu() * as long as the traversal is guarded by rcu_read_lock(). */struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, loff_t pos){ if (!pos) return SEQ_START_TOKEN;
return seq_hlist_start_rcu(head, pos - 1);}EXPORT_SYMBOL(seq_hlist_start_head_rcu);
/** * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU * @v: the current iterator * @head: the head of the hlist * @ppos: the current position * * Called at seq_file->op->next(). * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as hlist_add_head_rcu() * as long as the traversal is guarded by rcu_read_lock(). */struct hlist_node *seq_hlist_next_rcu(void *v, struct hlist_head *head, loff_t *ppos){ struct hlist_node *node = v;
++*ppos; if (v == SEQ_START_TOKEN) return rcu_dereference(head->first); else return rcu_dereference(node->next);}EXPORT_SYMBOL(seq_hlist_next_rcu);
/** * seq_hlist_start_percpu - 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);
void __init seq_file_init(void){ seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);}