Commit acce32a5 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: printbuf improvements 



- fix assorted (harmless) off-by-one errors
- we were inconsistent on whether out->pos stays <= out->size on
  overflow; now it does, and printbuf.overflow exists to indicate if a
  printbuf has overflowed
- factor out printbuf_advance_pos()
- printbuf_nul_terminate_reserved(); use this to reduce the number of
  printbuf_make_room() calls

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 62606398

fs/bcachefs/printbuf.c

+31 −34
Original line number Diff line number Diff line
@@ -17,28 +17,28 @@ static inline unsigned printbuf_linelen(struct printbuf *buf) 


int bch2_printbuf_make_room(struct printbuf *out, unsigned extra)

{

	unsigned new_size;

	char *buf;



	if (!out->heap_allocated)

		return 0;



	/* Reserved space for terminating nul: */

	extra += 1;



	if (out->pos + extra < out->size)

	if (out->pos + extra <= out->size)

		return 0;



	new_size = roundup_pow_of_two(out->size + extra);

	if (!out->heap_allocated) {

		out->overflow = true;

		return 0;

	}



	unsigned new_size = roundup_pow_of_two(out->size + extra);



	/*

	 * Note: output buffer must be freeable with kfree(), it's not required

	 * that the user use printbuf_exit().

	 */

	buf = krealloc(out->buf, new_size, !out->atomic ? GFP_KERNEL : GFP_NOWAIT);

	char *buf = krealloc(out->buf, new_size, !out->atomic ? GFP_KERNEL : GFP_NOWAIT);



	if (!buf) {

		out->allocation_failure = true;

		out->overflow = true;

		return -ENOMEM;

	}
@@ -47,6 +47,11 @@ int bch2_printbuf_make_room(struct printbuf *out, unsigned extra) 
	return 0;

}



static void printbuf_advance_pos(struct printbuf *out, unsigned len)

{

	out->pos += min(len, printbuf_remaining(out));

}



void bch2_prt_vprintf(struct printbuf *out, const char *fmt, va_list args)

{

	int len;
@@ -55,14 +60,12 @@ void bch2_prt_vprintf(struct printbuf *out, const char *fmt, va_list args) 
		va_list args2;



		va_copy(args2, args);

		len = vsnprintf(out->buf + out->pos, printbuf_remaining(out), fmt, args2);

		len = vsnprintf(out->buf + out->pos, printbuf_remaining_size(out), fmt, args2);

		va_end(args2);

	} while (len + 1 >= printbuf_remaining(out) &&

		 !bch2_printbuf_make_room(out, len + 1));

	} while (len > printbuf_remaining(out) &&

		 !bch2_printbuf_make_room(out, len));



	len = min_t(size_t, len,

		  printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0);

	out->pos += len;

	printbuf_advance_pos(out, len);

}



void bch2_prt_printf(struct printbuf *out, const char *fmt, ...)
@@ -72,14 +75,12 @@ void bch2_prt_printf(struct printbuf *out, const char *fmt, ...) 


	do {

		va_start(args, fmt);

		len = vsnprintf(out->buf + out->pos, printbuf_remaining(out), fmt, args);

		len = vsnprintf(out->buf + out->pos, printbuf_remaining_size(out), fmt, args);

		va_end(args);

	} while (len + 1 >= printbuf_remaining(out) &&

		 !bch2_printbuf_make_room(out, len + 1));

	} while (len > printbuf_remaining(out) &&

		 !bch2_printbuf_make_room(out, len));



	len = min_t(size_t, len,

		  printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0);

	out->pos += len;

	printbuf_advance_pos(out, len);

}



/**
@@ -194,18 +195,15 @@ void bch2_printbuf_indent_sub(struct printbuf *buf, unsigned spaces) 


void bch2_prt_newline(struct printbuf *buf)

{

	unsigned i;



	bch2_printbuf_make_room(buf, 1 + buf->indent);



	__prt_char(buf, '\n');

	__prt_char_reserved(buf, '\n');



	buf->last_newline	= buf->pos;



	for (i = 0; i < buf->indent; i++)

		__prt_char(buf, ' ');

	__prt_chars_reserved(buf, ' ', buf->indent);



	printbuf_nul_terminate(buf);

	printbuf_nul_terminate_reserved(buf);



	buf->last_field		= buf->pos;

	buf->cur_tabstop	= 0;
@@ -262,7 +260,7 @@ static void __prt_tab_rjust(struct printbuf *buf) 
			memset(buf->buf + buf->last_field, ' ',

			       min((unsigned) pad, buf->size - buf->last_field));



		buf->pos += pad;

		printbuf_advance_pos(buf, pad);

		printbuf_nul_terminate(buf);

	}
@@ -348,9 +346,10 @@ void bch2_prt_bytes_indented(struct printbuf *out, const char *str, unsigned cou 
void bch2_prt_human_readable_u64(struct printbuf *out, u64 v)

{

	bch2_printbuf_make_room(out, 10);

	out->pos += string_get_size(v, 1, !out->si_units,

	unsigned len = string_get_size(v, 1, !out->si_units,

				       out->buf + out->pos,

				       printbuf_remaining_size(out));

	printbuf_advance_pos(out, len);

}



/**
@@ -402,9 +401,7 @@ void bch2_prt_string_option(struct printbuf *out, 
			    const char * const list[],

			    size_t selected)

{

	size_t i;



	for (i = 0; list[i]; i++)

	for (size_t i = 0; list[i]; i++)

		bch2_prt_printf(out, i == selected ? "[%s] " : "%s ", list[i]);

}

fs/bcachefs/printbuf.h

+24 −29
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ struct printbuf { 
	u8			atomic;

	bool			allocation_failure:1;

	bool			heap_allocated:1;

	bool			overflow:1;

	enum printbuf_si	si_units:1;

	bool			human_readable_units:1;

	bool			has_indent_or_tabstops:1;
@@ -142,7 +143,9 @@ void bch2_prt_bitflags_vector(struct printbuf *, const char * const[], 
 */

static inline unsigned printbuf_remaining_size(struct printbuf *out)

{

	return out->pos < out->size ? out->size - out->pos : 0;

	if (WARN_ON(out->size && out->pos >= out->size))

		out->pos = out->size - 1;

	return out->size - out->pos;

}



/*
@@ -151,7 +154,7 @@ static inline unsigned printbuf_remaining_size(struct printbuf *out) 
 */

static inline unsigned printbuf_remaining(struct printbuf *out)

{

	return out->pos < out->size ? out->size - out->pos - 1 : 0;

	return out->size ? printbuf_remaining_size(out) - 1 : 0;

}



static inline unsigned printbuf_written(struct printbuf *out)
@@ -159,30 +162,25 @@ static inline unsigned printbuf_written(struct printbuf *out) 
	return out->size ? min(out->pos, out->size - 1) : 0;

}



/*

 * Returns true if output was truncated:

 */

static inline bool printbuf_overflowed(struct printbuf *out)

static inline void printbuf_nul_terminate_reserved(struct printbuf *out)

{

	return out->pos >= out->size;

	if (WARN_ON(out->size && out->pos >= out->size))

		out->pos = out->size - 1;

	if (out->size)

		out->buf[out->pos] = 0;

}



static inline void printbuf_nul_terminate(struct printbuf *out)

{

	bch2_printbuf_make_room(out, 1);



	if (out->pos < out->size)

		out->buf[out->pos] = 0;

	else if (out->size)

		out->buf[out->size - 1] = 0;

	printbuf_nul_terminate_reserved(out);

}



/* Doesn't call bch2_printbuf_make_room(), doesn't nul terminate: */

static inline void __prt_char_reserved(struct printbuf *out, char c)

{

	if (printbuf_remaining(out))

		out->buf[out->pos] = c;

	out->pos++;

		out->buf[out->pos++] = c;

}



/* Doesn't nul terminate: */
@@ -194,37 +192,34 @@ static inline void __prt_char(struct printbuf *out, char c) 


static inline void prt_char(struct printbuf *out, char c)

{

	__prt_char(out, c);

	printbuf_nul_terminate(out);

	bch2_printbuf_make_room(out, 2);

	__prt_char_reserved(out, c);

	printbuf_nul_terminate_reserved(out);

}



static inline void __prt_chars_reserved(struct printbuf *out, char c, unsigned n)

{

	unsigned i, can_print = min(n, printbuf_remaining(out));

	unsigned can_print = min(n, printbuf_remaining(out));



	for (i = 0; i < can_print; i++)

	for (unsigned i = 0; i < can_print; i++)

		out->buf[out->pos++] = c;

	out->pos += n - can_print;

}



static inline void prt_chars(struct printbuf *out, char c, unsigned n)

{

	bch2_printbuf_make_room(out, n);

	__prt_chars_reserved(out, c, n);

	printbuf_nul_terminate(out);

	printbuf_nul_terminate_reserved(out);

}



static inline void prt_bytes(struct printbuf *out, const void *b, unsigned n)

{

	unsigned i, can_print;



	bch2_printbuf_make_room(out, n);



	can_print = min(n, printbuf_remaining(out));

	unsigned can_print = min(n, printbuf_remaining(out));



	for (i = 0; i < can_print; i++)

	for (unsigned i = 0; i < can_print; i++)

		out->buf[out->pos++] = ((char *) b)[i];

	out->pos += n - can_print;



	printbuf_nul_terminate(out);

}
@@ -241,18 +236,18 @@ static inline void prt_str_indented(struct printbuf *out, const char *str) 


static inline void prt_hex_byte(struct printbuf *out, u8 byte)

{

	bch2_printbuf_make_room(out, 2);

	bch2_printbuf_make_room(out, 3);

	__prt_char_reserved(out, hex_asc_hi(byte));

	__prt_char_reserved(out, hex_asc_lo(byte));

	printbuf_nul_terminate(out);

	printbuf_nul_terminate_reserved(out);

}



static inline void prt_hex_byte_upper(struct printbuf *out, u8 byte)

{

	bch2_printbuf_make_room(out, 2);

	bch2_printbuf_make_room(out, 3);

	__prt_char_reserved(out, hex_asc_upper_hi(byte));

	__prt_char_reserved(out, hex_asc_upper_lo(byte));

	printbuf_nul_terminate(out);

	printbuf_nul_terminate_reserved(out);

}



/**