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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * seq_buf.c
  *
  * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
  *
  * The seq_buf is a handy tool that allows you to pass a descriptor around
  * to a buffer that other functions can write to. It is similar to the
  * seq_file functionality but has some differences.
  *
  * To use it, the seq_buf must be initialized with seq_buf_init().
  * This will set up the counters within the descriptor. You can call
  * seq_buf_init() more than once to reset the seq_buf to start
  * from scratch.
  */
 #include <linux/uaccess.h>
 #include <linux/seq_file.h>
 #include <linux/seq_buf.h>
 
 /**
  * seq_buf_can_fit - can the new data fit in the current buffer?
  * @s: the seq_buf descriptor
  * @len: The length to see if it can fit in the current buffer
  *
  * Returns true if there's enough unused space in the seq_buf buffer
  * to fit the amount of new data according to @len.
  */
 static bool seq_buf_can_fit(struct seq_buf *s, size_t len)
 {
     return s->len + len <= s->size;
 }
 
 /**
  * seq_buf_print_seq - move the contents of seq_buf into a seq_file
  * @m: the seq_file descriptor that is the destination
  * @s: the seq_buf descriptor that is the source.
  *
  * Returns zero on success, non zero otherwise
  */
 int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
 {
     unsigned int len = seq_buf_used(s);
 
     return seq_write(m, s->buffer, len);
 }
 
 /**
  * seq_buf_vprintf - sequence printing of information.
  * @s: seq_buf descriptor
  * @fmt: printf format string
  * @args: va_list of arguments from a printf() type function
  *
  * Writes a vnprintf() format into the sequencce buffer.
  *
  * Returns zero on success, -1 on overflow.
  */
 int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
 {
     int len;
 
     WARN_ON(s->size == 0);
 
     if (s->len < s->size) {
         len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
         if (s->len + len < s->size) {
             s->len += len;
             return 0;
         }
     }
     seq_buf_set_overflow(s);
     return -1;
 }
 
 /**
  * seq_buf_printf - sequence printing of information
  * @s: seq_buf descriptor
  * @fmt: printf format string
  *
  * Writes a printf() format into the sequence buffer.
  *
  * Returns zero on success, -1 on overflow.
  */
 int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
 {
     va_list ap;
     int ret;
 
     va_start(ap, fmt);
     ret = seq_buf_vprintf(s, fmt, ap);
     va_end(ap);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(seq_buf_printf);
 
 #ifdef CONFIG_BINARY_PRINTF
 /**
  * seq_buf_bprintf - Write the printf string from binary arguments
  * @s: seq_buf descriptor
  * @fmt: The format string for the @binary arguments
  * @binary: The binary arguments for @fmt.
  *
  * When recording in a fast path, a printf may be recorded with just
  * saving the format and the arguments as they were passed to the
  * function, instead of wasting cycles converting the arguments into
  * ASCII characters. Instead, the arguments are saved in a 32 bit
  * word array that is defined by the format string constraints.
  *
  * This function will take the format and the binary array and finish
  * the conversion into the ASCII string within the buffer.
  *
  * Returns zero on success, -1 on overflow.
  */
 int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
 {
     unsigned int len = seq_buf_buffer_left(s);
     int ret;
 
     WARN_ON(s->size == 0);
 
     if (s->len < s->size) {
         ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
         if (s->len + ret < s->size) {
             s->len += ret;
             return 0;
         }
     }
     seq_buf_set_overflow(s);
     return -1;
 }
 #endif /* CONFIG_BINARY_PRINTF */
 
 /**
  * seq_buf_puts - sequence printing of simple string
  * @s: seq_buf descriptor
  * @str: simple string to record
  *
  * Copy a simple string into the sequence buffer.
  *
  * Returns zero on success, -1 on overflow
  */
 int seq_buf_puts(struct seq_buf *s, const char *str)
 {
     size_t len = strlen(str);
 
     WARN_ON(s->size == 0);
 
     /* Add 1 to len for the trailing null byte which must be there */
     len += 1;
 
     if (seq_buf_can_fit(s, len)) {
         memcpy(s->buffer + s->len, str, len);
         /* Don't count the trailing null byte against the capacity */
         s->len += len - 1;
         return 0;
     }
     seq_buf_set_overflow(s);
     return -1;
 }
 
 /**
  * seq_buf_putc - sequence printing of simple character
  * @s: seq_buf descriptor
  * @c: simple character to record
  *
  * Copy a single character into the sequence buffer.
  *
  * Returns zero on success, -1 on overflow
  */
 int seq_buf_putc(struct seq_buf *s, unsigned char c)
 {
     WARN_ON(s->size == 0);
 
     if (seq_buf_can_fit(s, 1)) {
         s->buffer[s->len++] = c;
         return 0;
     }
     seq_buf_set_overflow(s);
     return -1;
 }
 
 /**
  * seq_buf_putmem - write raw data into the sequenc buffer
  * @s: seq_buf descriptor
  * @mem: The raw memory to copy into the buffer
  * @len: The length of the raw memory to copy (in bytes)
  *
  * There may be cases where raw memory needs to be written into the
  * buffer and a strcpy() would not work. Using this function allows
  * for such cases.
  *
  * Returns zero on success, -1 on overflow
  */
 int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
 {
     WARN_ON(s->size == 0);
 
     if (seq_buf_can_fit(s, len)) {
         memcpy(s->buffer + s->len, mem, len);
         s->len += len;
         return 0;
     }
     seq_buf_set_overflow(s);
     return -1;
 }
 
 #define MAX_MEMHEX_BYTES    8U
 #define HEX_CHARS       (MAX_MEMHEX_BYTES*2 + 1)
 
 /**
  * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
  * @s: seq_buf descriptor
  * @mem: The raw memory to write its hex ASCII representation of
  * @len: The length of the raw memory to copy (in bytes)
  *
  * This is similar to seq_buf_putmem() except instead of just copying the
  * raw memory into the buffer it writes its ASCII representation of it
  * in hex characters.
  *
  * Returns zero on success, -1 on overflow
  */
 int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
                unsigned int len)
 {
     unsigned char hex[HEX_CHARS];
     const unsigned char *data = mem;
     unsigned int start_len;
     int i, j;
 
     WARN_ON(s->size == 0);
 
     BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS);
 
     while (len) {
         start_len = min(len, MAX_MEMHEX_BYTES);
 #ifdef __BIG_ENDIAN
         for (i = 0, j = 0; i < start_len; i++) {
 #else
         for (i = start_len-1, j = 0; i >= 0; i--) {
 #endif
             hex[j++] = hex_asc_hi(data[i]);
             hex[j++] = hex_asc_lo(data[i]);
         }
         if (WARN_ON_ONCE(j == 0 || j/2 > len))
             break;
 
         /* j increments twice per loop */
         hex[j++] = ' ';
 
         seq_buf_putmem(s, hex, j);
         if (seq_buf_has_overflowed(s))
             return -1;
 
         len -= start_len;
         data += start_len;
     }
     return 0;
 }
 
 /**
  * seq_buf_path - copy a path into the sequence buffer
  * @s: seq_buf descriptor
  * @path: path to write into the sequence buffer.
  * @esc: set of characters to escape in the output
  *
  * Write a path name into the sequence buffer.
  *
  * Returns the number of written bytes on success, -1 on overflow
  */
 int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
 {
     char *buf;
     size_t size = seq_buf_get_buf(s, &buf);
     int res = -1;
 
     WARN_ON(s->size == 0);
 
     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_buf_commit(s, res);
 
     return res;
 }
 
 /**
  * seq_buf_to_user - copy the sequence buffer to user space
  * @s: seq_buf descriptor
  * @ubuf: The userspace memory location to copy to
  * @cnt: The amount to copy
  *
  * Copies the sequence buffer into the userspace memory pointed to
  * by @ubuf. It starts from the last read position (@s->readpos)
  * and writes up to @cnt characters or till it reaches the end of
  * the content in the buffer (@s->len), which ever comes first.
  *
  * On success, it returns a positive number of the number of bytes
  * it copied.
  *
  * On failure it returns -EBUSY if all of the content in the
  * sequence has been already read, which includes nothing in the
  * sequence (@s->len == @s->readpos).
  *
  * Returns -EFAULT if the copy to userspace fails.
  */
 int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
 {
     int len;
     int ret;
 
     if (!cnt)
         return 0;
 
     len = seq_buf_used(s);
 
     if (len <= s->readpos)
         return -EBUSY;
 
     len -= s->readpos;
     if (cnt > len)
         cnt = len;
     ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
     if (ret == cnt)
         return -EFAULT;
 
     cnt -= ret;
 
     s->readpos += cnt;
     return cnt;
 }
 
 /**
  * seq_buf_hex_dump - print formatted hex dump into the sequence buffer
  * @s: seq_buf descriptor
  * @prefix_str: string to prefix each line with;
  *  caller supplies trailing spaces for alignment if desired
  * @prefix_type: controls whether prefix of an offset, address, or none
  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
  * @rowsize: number of bytes to print per line; must be 16 or 32
  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
  * @buf: data blob to dump
  * @len: number of bytes in the @buf
  * @ascii: include ASCII after the hex output
  *
  * Function is an analogue of print_hex_dump() and thus has similar interface.
  *
  * linebuf size is maximal length for one line.
  * 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for
  *  separating space
  * 2 - spaces separating hex dump and ascii representation
  * 32 - ascii representation
  * 1 - terminating '\0'
  *
  * Returns zero on success, -1 on overflow
  */
 int seq_buf_hex_dump(struct seq_buf *s, 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;
     unsigned char linebuf[32 * 3 + 2 + 32 + 1];
     int ret;
 
     if (rowsize != 16 && rowsize != 32)
         rowsize = 16;
 
     for (i = 0; i < len; i += rowsize) {
         linelen = min(remaining, rowsize);
         remaining -= rowsize;
 
         hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
                    linebuf, sizeof(linebuf), ascii);
 
         switch (prefix_type) {
         case DUMP_PREFIX_ADDRESS:
             ret = seq_buf_printf(s, "%s%p: %s\n",
                    prefix_str, ptr + i, linebuf);
             break;
         case DUMP_PREFIX_OFFSET:
             ret = seq_buf_printf(s, "%s%.8x: %s\n",
                          prefix_str, i, linebuf);
             break;
         default:
             ret = seq_buf_printf(s, "%s%s\n", prefix_str, linebuf);
             break;
         }
         if (ret)
             return ret;
     }
     return 0;
 }

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