diff options
author | Varun Wadekar <vwadekar@nvidia.com> | 2012-04-07 01:52:57 +0530 |
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committer | Varun Wadekar <vwadekar@nvidia.com> | 2012-04-07 01:52:57 +0530 |
commit | 97caf63d0c837f9b5c9f6f469979e68c0378e83f (patch) | |
tree | c6fc834bcfb66268f474324eca619db419010532 /fs/seq_file.c | |
parent | 6a1a6f4f69adf0febfd923795b45edeff63e75ed (diff) |
Merge branch '3.4-rc1' into android-tegra-nv-3.3-rebased
Change-Id: Ib3b69ffc5ac3e07c9cc44cc49e9142088eec477e
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Diffstat (limited to 'fs/seq_file.c')
-rw-r--r-- | fs/seq_file.c | 114 |
1 files changed, 92 insertions, 22 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 4023d6be939b..0cbd0494b79e 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -6,13 +6,29 @@ */ #include <linux/fs.h> -#include <linux/module.h> +#include <linux/export.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <asm/uaccess.h> #include <asm/page.h> + +/* + * seq_files have a buffer which can may overflow. When this happens a larger + * buffer is reallocated and all the data will be printed again. + * The overflow state is true when m->count == m->size. + */ +static bool seq_overflow(struct seq_file *m) +{ + return m->count == m->size; +} + +static void seq_set_overflow(struct seq_file *m) +{ + m->count = m->size; +} + /** * seq_open - initialize sequential file * @file: file we initialize @@ -92,7 +108,7 @@ static int traverse(struct seq_file *m, loff_t offset) error = 0; m->count = 0; } - if (m->count == m->size) + if (seq_overflow(m)) goto Eoverflow; if (pos + m->count > offset) { m->from = offset - pos; @@ -140,9 +156,21 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) mutex_lock(&m->lock); + /* + * seq_file->op->..m_start/m_stop/m_next may do special actions + * or optimisations based on the file->f_version, so we want to + * pass the file->f_version to those methods. + * + * seq_file->version is just copy of f_version, and seq_file + * methods can treat it simply as file version. + * It is copied in first and copied out after all operations. + * It is convenient to have it as part of structure to avoid the + * need of passing another argument to all the seq_file methods. + */ + m->version = file->f_version; + /* Don't assume *ppos is where we left it */ if (unlikely(*ppos != m->read_pos)) { - m->read_pos = *ppos; while ((err = traverse(m, *ppos)) == -EAGAIN) ; if (err) { @@ -152,21 +180,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) m->index = 0; m->count = 0; goto Done; + } else { + m->read_pos = *ppos; } } - /* - * seq_file->op->..m_start/m_stop/m_next may do special actions - * or optimisations based on the file->f_version, so we want to - * pass the file->f_version to those methods. - * - * seq_file->version is just copy of f_version, and seq_file - * methods can treat it simply as file version. - * It is copied in first and copied out after all operations. - * It is convenient to have it as part of structure to avoid the - * need of passing another argument to all the seq_file methods. - */ - m->version = file->f_version; /* grab buffer if we didn't have one */ if (!m->buf) { m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); @@ -232,7 +250,7 @@ Fill: break; } err = m->op->show(m, p); - if (m->count == m->size || err) { + if (seq_overflow(m) || err) { m->count = offs; if (likely(err <= 0)) break; @@ -359,7 +377,7 @@ int seq_escape(struct seq_file *m, const char *s, const char *esc) *p++ = '0' + (c & 07); continue; } - m->count = m->size; + seq_set_overflow(m); return -1; } m->count = p - m->buf; @@ -381,7 +399,7 @@ int seq_printf(struct seq_file *m, const char *f, ...) return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_printf); @@ -510,7 +528,7 @@ int seq_bitmap(struct seq_file *m, const unsigned long *bits, return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_bitmap); @@ -526,7 +544,7 @@ int seq_bitmap_list(struct seq_file *m, const unsigned long *bits, return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_bitmap_list); @@ -637,11 +655,63 @@ int seq_puts(struct seq_file *m, const char *s) m->count += len; return 0; } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_puts); +/* + * A helper routine for putting decimal numbers without rich format of printf(). + * only 'unsigned long long' is supported. + * This routine will put one byte delimiter + number into seq_file. + * 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. + */ +int seq_put_decimal_ull(struct seq_file *m, char delimiter, + unsigned long long num) +{ + int len; + + if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */ + goto overflow; + + if (delimiter) + m->buf[m->count++] = delimiter; + + if (num < 10) { + m->buf[m->count++] = num + '0'; + return 0; + } + + len = num_to_str(m->buf + m->count, m->size - m->count, num); + if (!len) + goto overflow; + m->count += len; + return 0; +overflow: + seq_set_overflow(m); + return -1; +} +EXPORT_SYMBOL(seq_put_decimal_ull); + +int seq_put_decimal_ll(struct seq_file *m, char delimiter, + long long num) +{ + if (num < 0) { + if (m->count + 3 >= m->size) { + seq_set_overflow(m); + return -1; + } + if (delimiter) + m->buf[m->count++] = delimiter; + num = -num; + delimiter = '-'; + } + return seq_put_decimal_ull(m, delimiter, num); + +} +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 @@ -657,7 +727,7 @@ int seq_write(struct seq_file *seq, const void *data, size_t len) seq->count += len; return 0; } - seq->count = seq->size; + seq_set_overflow(seq); return -1; } EXPORT_SYMBOL(seq_write); |