From 7b039cb4c5a90d8ea576b17e096f7334457aeb57 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 26 Jun 2014 09:42:41 -0400 Subject: [PATCH] tracing: Add trace_seq_buffer_ptr() helper function There's several locations in the kernel that open code the calculation of the next location in the trace_seq buffer. This is usually done with p->buffer + p->len Instead of having this open coded, supply a helper function in the header to do it for them. This function is called trace_seq_buffer_ptr(). Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.org Acked-by: Paolo Bonzini Signed-off-by: Steven Rostedt --- arch/x86/kvm/mmutrace.h | 2 +- drivers/scsi/scsi_trace.c | 16 ++++++++-------- include/linux/trace_seq.h | 15 +++++++++++++++ kernel/trace/trace_output.c | 14 +++++++------- 4 files changed, 31 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h index 9d2e0ffcb190..2e5652b62fd6 100644 --- a/arch/x86/kvm/mmutrace.h +++ b/arch/x86/kvm/mmutrace.h @@ -22,7 +22,7 @@ __entry->unsync = sp->unsync; #define KVM_MMU_PAGE_PRINTK() ({ \ - const char *ret = p->buffer + p->len; \ + const char *ret = trace_seq_buffer_ptr(p); \ static const char *access_str[] = { \ "---", "--x", "w--", "w-x", "-u-", "-ux", "wu-", "wux" \ }; \ diff --git a/drivers/scsi/scsi_trace.c b/drivers/scsi/scsi_trace.c index 2bea4f0b684a..503594e5f76d 100644 --- a/drivers/scsi/scsi_trace.c +++ b/drivers/scsi/scsi_trace.c @@ -28,7 +28,7 @@ scsi_trace_misc(struct trace_seq *, unsigned char *, int); static const char * scsi_trace_rw6(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= ((cdb[1] & 0x1F) << 16); @@ -46,7 +46,7 @@ scsi_trace_rw6(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw10(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= (cdb[2] << 24); @@ -71,7 +71,7 @@ scsi_trace_rw10(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw12(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= (cdb[2] << 24); @@ -94,7 +94,7 @@ scsi_trace_rw12(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw16(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= ((u64)cdb[2] << 56); @@ -125,7 +125,7 @@ scsi_trace_rw16(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw32(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len, *cmd; + const char *ret = trace_seq_buffer_ptr(p), *cmd; sector_t lba = 0, txlen = 0; u32 ei_lbrt = 0; @@ -180,7 +180,7 @@ out: static const char * scsi_trace_unmap(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); unsigned int regions = cdb[7] << 8 | cdb[8]; trace_seq_printf(p, "regions=%u", (regions - 8) / 16); @@ -192,7 +192,7 @@ scsi_trace_unmap(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_service_action_in(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len, *cmd; + const char *ret = trace_seq_buffer_ptr(p), *cmd; sector_t lba = 0; u32 alloc_len = 0; @@ -247,7 +247,7 @@ scsi_trace_varlen(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_misc(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); trace_seq_printf(p, "-"); trace_seq_putc(p, 0); diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index dd85753e1bb0..ea6c9dea79e3 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -25,6 +25,21 @@ trace_seq_init(struct trace_seq *s) s->full = 0; } +/** + * trace_seq_buffer_ptr - return pointer to next location in buffer + * @s: trace sequence descriptor + * + * Returns the pointer to the buffer where the next write to + * the buffer will happen. This is useful to save the location + * that is about to be written to and then return the result + * of that write. + */ +static inline unsigned char * +trace_seq_buffer_ptr(struct trace_seq *s) +{ + return s->buffer + s->len; +} + /* * Currently only defined when tracing is enabled. */ diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index b8930f79a04b..c6977d5a9b12 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -75,7 +75,7 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim, { unsigned long mask; const char *str; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); int i, first = 1; for (i = 0; flag_array[i].name && flags; i++) { @@ -111,7 +111,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, const struct trace_print_flags *symbol_array) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; symbol_array[i].name; i++) { @@ -122,7 +122,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, break; } - if (ret == (const char *)(p->buffer + p->len)) + if (ret == (const char *)(trace_seq_buffer_ptr(p))) trace_seq_printf(p, "0x%lx", val); trace_seq_putc(p, 0); @@ -137,7 +137,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, const struct trace_print_flags_u64 *symbol_array) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; symbol_array[i].name; i++) { @@ -148,7 +148,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, break; } - if (ret == (const char *)(p->buffer + p->len)) + if (ret == (const char *)(trace_seq_buffer_ptr(p))) trace_seq_printf(p, "0x%llx", val); trace_seq_putc(p, 0); @@ -162,7 +162,7 @@ const char * ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr, unsigned int bitmask_size) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8); trace_seq_putc(p, 0); @@ -175,7 +175,7 @@ const char * ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; i < buf_len; i++) trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);