--- zzzz-none-000/linux-3.10.107/fs/seq_file.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/fs/seq_file.c 2021-02-04 17:41:59.000000000 +0000 @@ -8,26 +8,38 @@ #include #include #include +#include #include #include +#include +#include +#include #include #include - -/* - * 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) +static void seq_set_overflow(struct seq_file *m) { - return m->count == m->size; + m->count = m->size; } -static void seq_set_overflow(struct seq_file *m) +static void *seq_buf_alloc(unsigned long size) { - m->count = m->size; + void *buf; + gfp_t gfp = GFP_KERNEL; + + /* + * For high order allocations, use __GFP_NORETRY to avoid oom-killing - + * it's better to fall back to vmalloc() than to kill things. For small + * allocations, just use GFP_KERNEL which will oom kill, thus no need + * for vmalloc fallback. + */ + if (size > PAGE_SIZE) + gfp |= __GFP_NORETRY | __GFP_NOWARN; + buf = kmalloc(size, gfp); + if (!buf && size > PAGE_SIZE) + buf = vmalloc(size); + return buf; } /** @@ -43,23 +55,27 @@ * 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 = file->private_data; + struct seq_file *p; + + WARN_ON(file->private_data); + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + file->private_data = p; - if (!p) { - p = kmalloc(sizeof(*p), GFP_KERNEL); - if (!p) - return -ENOMEM; - file->private_data = p; - } - memset(p, 0, sizeof(*p)); mutex_init(&p->lock); p->op = op; -#ifdef CONFIG_USER_NS - p->user_ns = file->f_cred->user_ns; -#endif + + // No refcounting: the lifetime of 'p' is constrained + // to the lifetime of the file. + p->file = file; /* * Wrappers around seq_open(e.g. swaps_open) need to be @@ -96,7 +112,7 @@ 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; } @@ -112,7 +128,7 @@ error = 0; m->count = 0; } - if (seq_overflow(m)) + if (seq_has_overflowed(m)) goto Eoverflow; if (pos + m->count > offset) { m->from = offset - pos; @@ -135,8 +151,9 @@ 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 +208,7 @@ /* 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; } @@ -233,11 +250,11 @@ 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); @@ -256,7 +273,7 @@ break; } err = m->op->show(m, p); - if (seq_overflow(m) || err) { + if (seq_has_overflowed(m) || err) { m->count = offs; if (likely(err <= 0)) break; @@ -351,7 +368,7 @@ 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; } @@ -364,36 +381,21 @@ * @esc: set of characters that need escaping * * Puts string into buffer, replacing each occurrence of character from - * @esc with usual octal escape. Returns 0 in case of success, -1 - in - * case of overflow. + * @esc with usual octal escape. + * Use seq_has_overflowed() to check for errors. */ -int seq_escape(struct seq_file *m, const char *s, const char *esc) +void seq_escape(struct seq_file *m, const char *s, const char *esc) { - char *end = m->buf + m->size; - char *p; - char c; - - for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) { - if (!strchr(esc, c)) { - *p++ = c; - continue; - } - if (p + 3 < end) { - *p++ = '\\'; - *p++ = '0' + ((c & 0300) >> 6); - *p++ = '0' + ((c & 070) >> 3); - *p++ = '0' + (c & 07); - continue; - } - seq_set_overflow(m); - return -1; - } - m->count = p - m->buf; - return 0; + char *buf; + size_t size = seq_get_buf(m, &buf); + int ret; + + ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc); + seq_commit(m, ret < size ? ret : -1); } EXPORT_SYMBOL(seq_escape); -int seq_vprintf(struct seq_file *m, const char *f, va_list args) +void seq_vprintf(struct seq_file *m, const char *f, va_list args) { int len; @@ -401,24 +403,20 @@ len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); if (m->count + len < m->size) { m->count += len; - return 0; + return; } } seq_set_overflow(m); - return -1; } EXPORT_SYMBOL(seq_vprintf); -int seq_printf(struct seq_file *m, const char *f, ...) +void seq_printf(struct seq_file *m, const char *f, ...) { - int ret; va_list args; va_start(args, f); - ret = seq_vprintf(m, f, args); + seq_vprintf(m, f, args); va_end(args); - - return ret; } EXPORT_SYMBOL(seq_printf); @@ -483,6 +481,20 @@ } 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. */ @@ -534,38 +546,7 @@ return res; } - -int seq_bitmap(struct seq_file *m, const unsigned long *bits, - unsigned int nr_bits) -{ - if (m->count < m->size) { - int len = bitmap_scnprintf(m->buf + m->count, - m->size - m->count, bits, nr_bits); - if (m->count + len < m->size) { - m->count += len; - return 0; - } - } - seq_set_overflow(m); - return -1; -} -EXPORT_SYMBOL(seq_bitmap); - -int seq_bitmap_list(struct seq_file *m, const unsigned long *bits, - unsigned int nr_bits) -{ - if (m->count < m->size) { - int len = bitmap_scnlistprintf(m->buf + m->count, - m->size - m->count, bits, nr_bits); - if (m->count + len < m->size) { - m->count += len; - return 0; - } - } - seq_set_overflow(m); - return -1; -} -EXPORT_SYMBOL(seq_bitmap_list); +EXPORT_SYMBOL(seq_dentry); static void *single_start(struct seq_file *p, loff_t *pos) { @@ -606,13 +587,13 @@ int single_open_size(struct file *file, int (*show)(struct seq_file *, void *), void *data, size_t size) { - char *buf = kmalloc(size, GFP_KERNEL); + char *buf = seq_buf_alloc(size); int ret; if (!buf) return -ENOMEM; ret = single_open(file, show, data); if (ret) { - kfree(buf); + kvfree(buf); return ret; } ((struct seq_file *)file->private_data)->buf = buf; @@ -673,26 +654,25 @@ } EXPORT_SYMBOL(seq_open_private); -int seq_putc(struct seq_file *m, char c) +void seq_putc(struct seq_file *m, char c) { - if (m->count < m->size) { - m->buf[m->count++] = c; - return 0; - } - return -1; + if (m->count >= m->size) + return; + + m->buf[m->count++] = c; } EXPORT_SYMBOL(seq_putc); -int seq_puts(struct seq_file *m, const char *s) +void seq_puts(struct seq_file *m, const char *s) { int len = strlen(s); - if (m->count + len < m->size) { - memcpy(m->buf + m->count, s, len); - m->count += len; - return 0; + + if (m->count + len >= m->size) { + seq_set_overflow(m); + return; } - seq_set_overflow(m); - return -1; + memcpy(m->buf + m->count, s, len); + m->count += len; } EXPORT_SYMBOL(seq_puts); @@ -703,8 +683,8 @@ * 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) +void seq_put_decimal_ull(struct seq_file *m, char delimiter, + unsigned long long num) { int len; @@ -716,35 +696,33 @@ if (num < 10) { m->buf[m->count++] = num + '0'; - return 0; + return; } len = num_to_str(m->buf + m->count, m->size - m->count, num); if (!len) goto overflow; m->count += len; - return 0; + return; + 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) +void 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; + return; } if (delimiter) m->buf[m->count++] = delimiter; num = -num; delimiter = '-'; } - return seq_put_decimal_ull(m, delimiter, num); - + seq_put_decimal_ull(m, delimiter, num); } EXPORT_SYMBOL(seq_put_decimal_ll); @@ -768,6 +746,61 @@ } 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); + +/* 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; @@ -925,3 +958,57 @@ 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);