On Mon, 29 Sep 2014 13:58:55 +0200 Hannes Reinecke <h...@suse.de> wrote:
> From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org> > > The seq_buf functions are rather useful outside of tracing. Instead > of having it be dependent on CONFIG_TRACING, move the code into lib/ > and allow other users to have access to it even when tracing is not > configured. > > The seq_buf utility is similar to the seq_file utility, but instead of > writing sending data back up to userland, it writes it into a buffer > defined at seq_buf_init(). This allows us to send a descriptor around > that writes printf() formatted strings into it that can be retrieved > later. > > It is currently used by the tracing facility for such things like trace > events to convert its binary saved data in the ring buffer into an > ASCII human readable context to be displayed in /sys/kernel/debug/trace. > > It can also be used for doing NMI prints safely from NMI context into > the seq_buf and retrieved later and dumped to printk() safely. Doing > printk() from an NMI context is dangerous because an NMI can preempt > a current printk() and deadlock on it. > > Link: http://lkml.kernel.org/p/20140619213952.058255...@goodmis.org I don't know where this is going, but I'm currently rewriting this code. Please don't add it yet to the kernel yet. I'm working on getting seq_buf and seq_file to be more inlined with each other. A much better sell if we can remove code with this change. -- Steve > > Acked-by: Hannes Reinecke <h...@suse.de> > Signed-off-by: Steven Rostedt <rost...@goodmis.org> > --- > kernel/trace/Makefile | 1 - > kernel/trace/seq_buf.c | 348 > ------------------------------------------------- > lib/Makefile | 2 +- > lib/seq_buf.c | 348 > +++++++++++++++++++++++++++++++++++++++++++++++++ > lib/trace_seq.c | 303 ++++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 652 insertions(+), 350 deletions(-) > delete mode 100644 kernel/trace/seq_buf.c > create mode 100644 lib/seq_buf.c > create mode 100644 lib/trace_seq.c > > diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile > index edc98c7..67d6369 100644 > --- a/kernel/trace/Makefile > +++ b/kernel/trace/Makefile > @@ -29,7 +29,6 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += > ring_buffer_benchmark.o > obj-$(CONFIG_TRACING) += trace.o > obj-$(CONFIG_TRACING) += trace_output.o > obj-$(CONFIG_TRACING) += trace_seq.o > -obj-$(CONFIG_TRACING) += seq_buf.o > obj-$(CONFIG_TRACING) += trace_stat.o > obj-$(CONFIG_TRACING) += trace_printk.o > obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o > diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c > deleted file mode 100644 > index 5c3c65b..0000000 > --- a/kernel/trace/seq_buf.c > +++ /dev/null > @@ -1,348 +0,0 @@ > -/* > - * seq_buf.c > - * > - * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srost...@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> > - > -/* How much buffer is left on the seq_buf? */ > -#define SEQ_BUF_LEFT(s) (((s)->size - 1) - (s)->len) > - > -/* How much buffer is written? */ > -#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1) > - > -static inline void seq_buf_check_len(struct seq_buf *s) > -{ > - if (unlikely(s->len > (s->size - 1))) { > - s->len = s->size - 1; > - s->overflow = 1; > - } > -} > - > -/** > - * 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_printf - sequence printing of trace information > - * @s: seq_buf descriptor > - * @fmt: printf format string > - * > - * Writes a printf() format into the sequence buffer. > - * > - * Returns number of bytes written. > - */ > -int seq_buf_printf(struct seq_buf *s, const char *fmt, ...) > -{ > - unsigned int len = SEQ_BUF_LEFT(s); > - va_list ap; > - int ret; > - > - WARN_ON((int)len < 0); > - va_start(ap, fmt); > - ret = vsnprintf(s->buffer + s->len, len, fmt, ap); > - va_end(ap); > - > - s->len += ret; > - > - seq_buf_check_len(s); > - > - return ret; > -} > - > -/** > - * seq_buf_bitmask - write a bitmask array in its ASCII representation > - * @s: seq_buf descriptor > - * @maskp: points to an array of unsigned longs that represent a bitmask > - * @nmaskbits: The number of bits that are valid in @maskp > - * > - * Writes a ASCII representation of a bitmask string into @s. > - * > - * Returns the number of bytes written. > - */ > -int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp, > - int nmaskbits) > -{ > - unsigned int len = SEQ_BUF_LEFT(s); > - int ret; > - > - WARN_ON((int)len < 0); > - ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); > - s->len += ret; > - seq_buf_check_len(s); > - > - return ret; > -} > - > -/** > - * seq_buf_vprintf - write vprintf style into the sequence buffer > - * @s: seq_buf descriptor > - * @fmt: printf format string > - * > - * Write a vprintf() style into the sequence buffer. > - * > - * Returns the number of bytes written. > - */ > -int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args) > -{ > - unsigned int len = SEQ_BUF_LEFT(s); > - int ret; > - > - if (WARN_ON((int)len < 0)) > - printk("len=%d size=%d s->len=%d\n", len, s->size, s->len); > - ret = vsnprintf(s->buffer + s->len, len, fmt, args); > - s->len += ret; > - seq_buf_check_len(s); > - > - return len; > -} > - > -/** > - * 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 number of bytes written. > - */ > -int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary) > -{ > - unsigned int len = SEQ_BUF_LEFT(s); > - int ret; > - > - if (WARN_ON((int)len < 0)) > - printk("len=%d size=%d s->len=%d\n", len, s->size, s->len); > - ret = bstr_printf(s->buffer + s->len, len, fmt, binary); > - s->len += ret; > - seq_buf_check_len(s); > - > - return len; > -} > - > -/** > - * 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 number of bytes written. > - */ > -int seq_buf_puts(struct seq_buf *s, const char *str) > -{ > - unsigned int len = strlen(str); > - > - if (len > SEQ_BUF_LEFT(s)) { > - s->overflow = 1; > - len = SEQ_BUF_LEFT(s); > - } > - > - memcpy(s->buffer + s->len, str, len); > - s->len += len; > - WARN_ON(s->len > (s->size - 1)); > - > - return len; > -} > - > -/** > - * 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 1 if the character was written, 0 otherwise. > - */ > -int seq_buf_putc(struct seq_buf *s, unsigned char c) > -{ > - if (SEQ_BUF_LEFT(s) < 1) { > - s->overflow = 1; > - return 0; > - } > - > - s->buffer[s->len++] = c; > - WARN_ON(s->len > (s->size - 1)); > - > - 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 the number of bytes written in the buffer. > - */ > -int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len) > -{ > - if (len > SEQ_BUF_LEFT(s)) { > - s->overflow = 1; > - len = SEQ_BUF_LEFT(s); > - } > - > - memcpy(s->buffer + s->len, mem, len); > - s->len += len; > - WARN_ON(s->len > (s->size - 1)); > - > - return len; > -} > - > -#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 how much it wrote to the buffer. > - */ > -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; > - int cnt = 0; > - > - while (len) { > - start_len = min(len, HEX_CHARS - 1); > -#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 */ > - len -= j / 2; > - hex[j++] = ' '; > - > - cnt += seq_buf_putmem(s, hex, j); > - } > - return cnt; > -} > - > -/** > - * seq_buf_path - copy a path into the sequence buffer > - * @s: seq_buf descriptor > - * @path: path to write into the sequence buffer. > - * > - * Write a path name into the sequence buffer. > - * > - * Returns the number of bytes written into the buffer. > - */ > -int seq_buf_path(struct seq_buf *s, const struct path *path) > -{ > - unsigned int len = SEQ_BUF_LEFT(s); > - unsigned char *p; > - unsigned int start = s->len; > - > - WARN_ON((int)len < 0); > - p = d_path(path, s->buffer + s->len, len); > - if (!IS_ERR(p)) { > - p = mangle_path(s->buffer + s->len, p, "\n"); > - if (p) { > - s->len = p - s->buffer; > - WARN_ON(s->len > (s->size - 1)); > - return s->len - start; > - } > - } else { > - s->buffer[s->len++] = '?'; > - WARN_ON(s->len > (s->size - 1)); > - return s->len - start; > - } > - > - s->overflow = 1; > - return 0; > -} > - > -/** > - * seq_buf_to_user - copy the squence 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 > - * sequenc (@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; > - > - if (s->len <= s->readpos) > - return -EBUSY; > - > - len = s->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; > -} > diff --git a/lib/Makefile b/lib/Makefile > index d6b4bc4..b2b0572 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -13,7 +13,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ > sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \ > proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \ > is_single_threaded.o plist.o decompress.o kobject_uevent.o \ > - earlycpio.o > + earlycpio.o seq_buf.o > > obj-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o > lib-$(CONFIG_MMU) += ioremap.o > diff --git a/lib/seq_buf.c b/lib/seq_buf.c > new file mode 100644 > index 0000000..5c3c65b > --- /dev/null > +++ b/lib/seq_buf.c > @@ -0,0 +1,348 @@ > +/* > + * seq_buf.c > + * > + * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srost...@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> > + > +/* How much buffer is left on the seq_buf? */ > +#define SEQ_BUF_LEFT(s) (((s)->size - 1) - (s)->len) > + > +/* How much buffer is written? */ > +#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1) > + > +static inline void seq_buf_check_len(struct seq_buf *s) > +{ > + if (unlikely(s->len > (s->size - 1))) { > + s->len = s->size - 1; > + s->overflow = 1; > + } > +} > + > +/** > + * 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_printf - sequence printing of trace information > + * @s: seq_buf descriptor > + * @fmt: printf format string > + * > + * Writes a printf() format into the sequence buffer. > + * > + * Returns number of bytes written. > + */ > +int seq_buf_printf(struct seq_buf *s, const char *fmt, ...) > +{ > + unsigned int len = SEQ_BUF_LEFT(s); > + va_list ap; > + int ret; > + > + WARN_ON((int)len < 0); > + va_start(ap, fmt); > + ret = vsnprintf(s->buffer + s->len, len, fmt, ap); > + va_end(ap); > + > + s->len += ret; > + > + seq_buf_check_len(s); > + > + return ret; > +} > + > +/** > + * seq_buf_bitmask - write a bitmask array in its ASCII representation > + * @s: seq_buf descriptor > + * @maskp: points to an array of unsigned longs that represent a bitmask > + * @nmaskbits: The number of bits that are valid in @maskp > + * > + * Writes a ASCII representation of a bitmask string into @s. > + * > + * Returns the number of bytes written. > + */ > +int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp, > + int nmaskbits) > +{ > + unsigned int len = SEQ_BUF_LEFT(s); > + int ret; > + > + WARN_ON((int)len < 0); > + ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); > + s->len += ret; > + seq_buf_check_len(s); > + > + return ret; > +} > + > +/** > + * seq_buf_vprintf - write vprintf style into the sequence buffer > + * @s: seq_buf descriptor > + * @fmt: printf format string > + * > + * Write a vprintf() style into the sequence buffer. > + * > + * Returns the number of bytes written. > + */ > +int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args) > +{ > + unsigned int len = SEQ_BUF_LEFT(s); > + int ret; > + > + if (WARN_ON((int)len < 0)) > + printk("len=%d size=%d s->len=%d\n", len, s->size, s->len); > + ret = vsnprintf(s->buffer + s->len, len, fmt, args); > + s->len += ret; > + seq_buf_check_len(s); > + > + return len; > +} > + > +/** > + * 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 number of bytes written. > + */ > +int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary) > +{ > + unsigned int len = SEQ_BUF_LEFT(s); > + int ret; > + > + if (WARN_ON((int)len < 0)) > + printk("len=%d size=%d s->len=%d\n", len, s->size, s->len); > + ret = bstr_printf(s->buffer + s->len, len, fmt, binary); > + s->len += ret; > + seq_buf_check_len(s); > + > + return len; > +} > + > +/** > + * 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 number of bytes written. > + */ > +int seq_buf_puts(struct seq_buf *s, const char *str) > +{ > + unsigned int len = strlen(str); > + > + if (len > SEQ_BUF_LEFT(s)) { > + s->overflow = 1; > + len = SEQ_BUF_LEFT(s); > + } > + > + memcpy(s->buffer + s->len, str, len); > + s->len += len; > + WARN_ON(s->len > (s->size - 1)); > + > + return len; > +} > + > +/** > + * 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 1 if the character was written, 0 otherwise. > + */ > +int seq_buf_putc(struct seq_buf *s, unsigned char c) > +{ > + if (SEQ_BUF_LEFT(s) < 1) { > + s->overflow = 1; > + return 0; > + } > + > + s->buffer[s->len++] = c; > + WARN_ON(s->len > (s->size - 1)); > + > + 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 the number of bytes written in the buffer. > + */ > +int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len) > +{ > + if (len > SEQ_BUF_LEFT(s)) { > + s->overflow = 1; > + len = SEQ_BUF_LEFT(s); > + } > + > + memcpy(s->buffer + s->len, mem, len); > + s->len += len; > + WARN_ON(s->len > (s->size - 1)); > + > + return len; > +} > + > +#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 how much it wrote to the buffer. > + */ > +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; > + int cnt = 0; > + > + while (len) { > + start_len = min(len, HEX_CHARS - 1); > +#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 */ > + len -= j / 2; > + hex[j++] = ' '; > + > + cnt += seq_buf_putmem(s, hex, j); > + } > + return cnt; > +} > + > +/** > + * seq_buf_path - copy a path into the sequence buffer > + * @s: seq_buf descriptor > + * @path: path to write into the sequence buffer. > + * > + * Write a path name into the sequence buffer. > + * > + * Returns the number of bytes written into the buffer. > + */ > +int seq_buf_path(struct seq_buf *s, const struct path *path) > +{ > + unsigned int len = SEQ_BUF_LEFT(s); > + unsigned char *p; > + unsigned int start = s->len; > + > + WARN_ON((int)len < 0); > + p = d_path(path, s->buffer + s->len, len); > + if (!IS_ERR(p)) { > + p = mangle_path(s->buffer + s->len, p, "\n"); > + if (p) { > + s->len = p - s->buffer; > + WARN_ON(s->len > (s->size - 1)); > + return s->len - start; > + } > + } else { > + s->buffer[s->len++] = '?'; > + WARN_ON(s->len > (s->size - 1)); > + return s->len - start; > + } > + > + s->overflow = 1; > + return 0; > +} > + > +/** > + * seq_buf_to_user - copy the squence 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 > + * sequenc (@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; > + > + if (s->len <= s->readpos) > + return -EBUSY; > + > + len = s->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; > +} > diff --git a/lib/trace_seq.c b/lib/trace_seq.c > new file mode 100644 > index 0000000..5ba99c6c > --- /dev/null > +++ b/lib/trace_seq.c > @@ -0,0 +1,303 @@ > +/* > + * trace_seq.c > + * > + * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt <srost...@redhat.com> > + * > + */ > +#include <linux/uaccess.h> > +#include <linux/seq_file.h> > +#include <linux/trace_seq.h> > + > +int trace_print_seq(struct seq_file *m, struct trace_seq *s) > +{ > + int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; > + int ret; > + > + ret = seq_write(m, s->buffer, len); > + > + /* > + * Only reset this buffer if we successfully wrote to the > + * seq_file buffer. > + */ > + if (!ret) > + trace_seq_init(s); > + > + return ret; > +} > + > +/** > + * trace_seq_printf - sequence printing of trace information > + * @s: trace sequence descriptor > + * @fmt: printf format string > + * > + * It returns 0 if the trace oversizes the buffer's free > + * space, 1 otherwise. > + * > + * The tracer may use either sequence operations or its own > + * copy to user routines. To simplify formating of a trace > + * trace_seq_printf is used to store strings into a special > + * buffer (@s). Then the output may be either used by > + * the sequencer or pulled into another buffer. > + */ > +int > +trace_seq_printf(struct trace_seq *s, const char *fmt, ...) > +{ > + int len = (PAGE_SIZE - 1) - s->len; > + va_list ap; > + int ret; > + > + if (s->full || !len) > + return 0; > + > + va_start(ap, fmt); > + ret = vsnprintf(s->buffer + s->len, len, fmt, ap); > + va_end(ap); > + > + /* If we can't write it all, don't bother writing anything */ > + if (ret >= len) { > + s->full = 1; > + return 0; > + } > + > + s->len += ret; > + > + return 1; > +} > +EXPORT_SYMBOL_GPL(trace_seq_printf); > + > +/** > + * trace_seq_bitmask - put a list of longs as a bitmask print output > + * @s: trace sequence descriptor > + * @maskp: points to an array of unsigned longs that represent a bitmask > + * @nmaskbits: The number of bits that are valid in @maskp > + * > + * It returns 0 if the trace oversizes the buffer's free > + * space, 1 otherwise. > + * > + * Writes a ASCII representation of a bitmask string into @s. > + */ > +int > +trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, > + int nmaskbits) > +{ > + int len = (PAGE_SIZE - 1) - s->len; > + int ret; > + > + if (s->full || !len) > + return 0; > + > + ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); > + s->len += ret; > + > + return 1; > +} > +EXPORT_SYMBOL_GPL(trace_seq_bitmask); > + > +/** > + * trace_seq_vprintf - sequence printing of trace information > + * @s: trace sequence descriptor > + * @fmt: printf format string > + * > + * The tracer may use either sequence operations or its own > + * copy to user routines. To simplify formating of a trace > + * trace_seq_printf is used to store strings into a special > + * buffer (@s). Then the output may be either used by > + * the sequencer or pulled into another buffer. > + */ > +int > +trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) > +{ > + int len = (PAGE_SIZE - 1) - s->len; > + int ret; > + > + if (s->full || !len) > + return 0; > + > + ret = vsnprintf(s->buffer + s->len, len, fmt, args); > + > + /* If we can't write it all, don't bother writing anything */ > + if (ret >= len) { > + s->full = 1; > + return 0; > + } > + > + s->len += ret; > + > + return len; > +} > +EXPORT_SYMBOL_GPL(trace_seq_vprintf); > + > +int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 > *binary) > +{ > + int len = (PAGE_SIZE - 1) - s->len; > + int ret; > + > + if (s->full || !len) > + return 0; > + > + ret = bstr_printf(s->buffer + s->len, len, fmt, binary); > + > + /* If we can't write it all, don't bother writing anything */ > + if (ret >= len) { > + s->full = 1; > + return 0; > + } > + > + s->len += ret; > + > + return len; > +} > + > +/** > + * trace_seq_puts - trace sequence printing of simple string > + * @s: trace sequence descriptor > + * @str: simple string to record > + * > + * The tracer may use either the sequence operations or its own > + * copy to user routines. This function records a simple string > + * into a special buffer (@s) for later retrieval by a sequencer > + * or other mechanism. > + */ > +int trace_seq_puts(struct trace_seq *s, const char *str) > +{ > + int len = strlen(str); > + > + if (s->full) > + return 0; > + > + if (len > ((PAGE_SIZE - 1) - s->len)) { > + s->full = 1; > + return 0; > + } > + > + memcpy(s->buffer + s->len, str, len); > + s->len += len; > + > + return len; > +} > + > +int trace_seq_putc(struct trace_seq *s, unsigned char c) > +{ > + if (s->full) > + return 0; > + > + if (s->len >= (PAGE_SIZE - 1)) { > + s->full = 1; > + return 0; > + } > + > + s->buffer[s->len++] = c; > + > + return 1; > +} > +EXPORT_SYMBOL(trace_seq_putc); > + > +int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) > +{ > + if (s->full) > + return 0; > + > + if (len > ((PAGE_SIZE - 1) - s->len)) { > + s->full = 1; > + return 0; > + } > + > + memcpy(s->buffer + s->len, mem, len); > + s->len += len; > + > + return len; > +} > + > +#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) > + > +int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) > +{ > + unsigned char hex[HEX_CHARS]; > + const unsigned char *data = mem; > + int i, j; > + > + if (s->full) > + return 0; > + > +#ifdef __BIG_ENDIAN > + for (i = 0, j = 0; i < len; i++) { > +#else > + for (i = len-1, j = 0; i >= 0; i--) { > +#endif > + hex[j++] = hex_asc_hi(data[i]); > + hex[j++] = hex_asc_lo(data[i]); > + } > + hex[j++] = ' '; > + > + return trace_seq_putmem(s, hex, j); > +} > + > +void *trace_seq_reserve(struct trace_seq *s, size_t len) > +{ > + void *ret; > + > + if (s->full) > + return NULL; > + > + if (len > ((PAGE_SIZE - 1) - s->len)) { > + s->full = 1; > + return NULL; > + } > + > + ret = s->buffer + s->len; > + s->len += len; > + > + return ret; > +} > + > +int trace_seq_path(struct trace_seq *s, const struct path *path) > +{ > + unsigned char *p; > + > + if (s->full) > + return 0; > + > + if (s->len >= (PAGE_SIZE - 1)) { > + s->full = 1; > + return 0; > + } > + > + p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); > + if (!IS_ERR(p)) { > + p = mangle_path(s->buffer + s->len, p, "\n"); > + if (p) { > + s->len = p - s->buffer; > + return 1; > + } > + } else { > + s->buffer[s->len++] = '?'; > + return 1; > + } > + > + s->full = 1; > + return 0; > +} > + > +ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) > +{ > + int len; > + int ret; > + > + if (!cnt) > + return 0; > + > + if (s->len <= s->readpos) > + return -EBUSY; > + > + len = s->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; > +} -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
