blktrace.c: Make thread-safe by removing local static variables

Local static variables are not thread-safe. Make the functions in
blktrace.c safe by replacing them.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Link: https://lore.kernel.org/r/b805bb3f6acf6c5b4d8811872c62af939aac62a7.1642626314.git.lukasstraub2@web.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/blktrace.c b/blktrace.c
index 1faa83bf0332f953b9eec619006c3ecf729c2478..e18047658953f718fdded2212bee42237c42ac9a 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -13,6 +13,12 @@
 #include "blktrace_api.h"
 #include "oslib/linux-dev-lookup.h"
 
+struct file_cache {
+       unsigned int maj;
+       unsigned int min;
+       unsigned int fileno;
+};
+
 /*
  * Just discard the pdu by seeking past it.
  */
@@ -87,28 +93,28 @@ static void trace_add_open_close_event(struct thread_data *td, int fileno, enum
        flist_add_tail(&ipo->list, &td->io_log_list);
 }
 
-static int trace_add_file(struct thread_data *td, __u32 device)
+static int trace_add_file(struct thread_data *td, __u32 device,
+                         struct file_cache *cache)
 {
-       static unsigned int last_maj, last_min, last_fileno;
        unsigned int maj = FMAJOR(device);
        unsigned int min = FMINOR(device);
        struct fio_file *f;
        char dev[256];
        unsigned int i;
 
-       if (last_maj == maj && last_min == min)
-               return last_fileno;
+       if (cache->maj == maj && cache->min == min)
+               return cache->fileno;
 
-       last_maj = maj;
-       last_min = min;
+       cache->maj = maj;
+       cache->min = min;
 
        /*
         * check for this file in our list
         */
        for_each_file(td, f, i)
                if (f->major == maj && f->minor == min) {
-                       last_fileno = f->fileno;
-                       return last_fileno;
+                       cache->fileno = f->fileno;
+                       return cache->fileno;
                }
 
        strcpy(dev, "/dev");
@@ -128,10 +134,10 @@ static int trace_add_file(struct thread_data *td, __u32 device)
                td->files[fileno]->major = maj;
                td->files[fileno]->minor = min;
                trace_add_open_close_event(td, fileno, FIO_LOG_OPEN_FILE);
-               last_fileno = fileno;
+               cache->fileno = fileno;
        }
 
-       return last_fileno;
+       return cache->fileno;
 }
 
 static void t_bytes_align(struct thread_options *o, struct blk_io_trace *t)
@@ -195,7 +201,8 @@ static bool handle_trace_notify(struct blk_io_trace *t)
 static bool handle_trace_discard(struct thread_data *td,
                                 struct blk_io_trace *t,
                                 unsigned long long ttime,
-                                unsigned long *ios, unsigned long long *bs)
+                                unsigned long *ios, unsigned long long *bs,
+                                struct file_cache *cache)
 {
        struct io_piece *ipo;
        int fileno;
@@ -205,7 +212,7 @@ static bool handle_trace_discard(struct thread_data *td,
 
        ipo = calloc(1, sizeof(*ipo));
        init_ipo(ipo);
-       fileno = trace_add_file(td, t->device);
+       fileno = trace_add_file(td, t->device, cache);
 
        ios[DDIR_TRIM]++;
        if (t->bytes > bs[DDIR_TRIM])
@@ -238,12 +245,12 @@ static void dump_trace(struct blk_io_trace *t)
 
 static bool handle_trace_fs(struct thread_data *td, struct blk_io_trace *t,
                            unsigned long long ttime, unsigned long *ios,
-                           unsigned long long *bs)
+                           unsigned long long *bs, struct file_cache *cache)
 {
        int rw;
        int fileno;
 
-       fileno = trace_add_file(td, t->device);
+       fileno = trace_add_file(td, t->device, cache);
 
        rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;
 
@@ -271,7 +278,8 @@ static bool handle_trace_fs(struct thread_data *td, struct blk_io_trace *t,
 }
 
 static bool handle_trace_flush(struct thread_data *td, struct blk_io_trace *t,
-                              unsigned long long ttime, unsigned long *ios)
+                              unsigned long long ttime, unsigned long *ios,
+                              struct file_cache *cache)
 {
        struct io_piece *ipo;
        int fileno;
@@ -281,7 +289,7 @@ static bool handle_trace_flush(struct thread_data *td, struct blk_io_trace *t,
 
        ipo = calloc(1, sizeof(*ipo));
        init_ipo(ipo);
-       fileno = trace_add_file(td, t->device);
+       fileno = trace_add_file(td, t->device, cache);
 
        ipo->delay = ttime / 1000;
        ipo->ddir = DDIR_SYNC;
@@ -298,28 +306,29 @@ static bool handle_trace_flush(struct thread_data *td, struct blk_io_trace *t,
  * due to internal workings of the block layer.
  */
 static bool queue_trace(struct thread_data *td, struct blk_io_trace *t,
-                        unsigned long *ios, unsigned long long *bs)
+                        unsigned long *ios, unsigned long long *bs,
+                        struct file_cache *cache)
 {
-       static unsigned long long last_ttime;
+       unsigned long long *last_ttime = &td->io_log_blktrace_last_ttime;
        unsigned long long delay = 0;
 
        if ((t->action & 0xffff) != __BLK_TA_QUEUE)
                return false;
 
        if (!(t->action & BLK_TC_ACT(BLK_TC_NOTIFY))) {
-               if (!last_ttime || td->o.no_stall || t->time < last_ttime)
+               if (!*last_ttime || td->o.no_stall || t->time < *last_ttime)
                        delay = 0;
                else if (td->o.replay_time_scale == 100)
-                       delay = t->time - last_ttime;
+                       delay = t->time - *last_ttime;
                else {
-                       double tmp = t->time - last_ttime;
+                       double tmp = t->time - *last_ttime;
                        double scale;
 
                        scale = (double) 100.0 / (double) td->o.replay_time_scale;
                        tmp *= scale;
                        delay = tmp;
                }
-               last_ttime = t->time;
+               *last_ttime = t->time;
        }
 
        t_bytes_align(&td->o, t);
@@ -327,11 +336,11 @@ static bool queue_trace(struct thread_data *td, struct blk_io_trace *t,
        if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
                return handle_trace_notify(t);
        else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
-               return handle_trace_discard(td, t, delay, ios, bs);
+               return handle_trace_discard(td, t, delay, ios, bs, cache);
        else if (t->action & BLK_TC_ACT(BLK_TC_FLUSH))
-               return handle_trace_flush(td, t, delay, ios);
+               return handle_trace_flush(td, t, delay, ios, cache);
        else
-               return handle_trace_fs(td, t, delay, ios, bs);
+               return handle_trace_fs(td, t, delay, ios, bs, cache);
 }
 
 static void byteswap_trace(struct blk_io_trace *t)
@@ -409,6 +418,7 @@ bool init_blktrace_read(struct thread_data *td, const char *filename, int need_s
                goto err;
        }
        td->io_log_blktrace_swap = need_swap;
+       td->io_log_blktrace_last_ttime = 0;
        td->o.size = 0;
 
        free_release_files(td);
@@ -439,6 +449,7 @@ err:
 bool read_blktrace(struct thread_data* td)
 {
        struct blk_io_trace t;
+       struct file_cache cache = { };
        unsigned long ios[DDIR_RWDIR_SYNC_CNT] = { };
        unsigned long long rw_bs[DDIR_RWDIR_CNT] = { };
        unsigned long skipped_writes;
@@ -502,7 +513,7 @@ bool read_blktrace(struct thread_data* td)
                        }
                }
 
-               if (!queue_trace(td, &t, ios, rw_bs))
+               if (!queue_trace(td, &t, ios, rw_bs, &cache))
                        continue;
 
                if (td->o.read_iolog_chunked) {

diff --git a/fio.h b/fio.h
index 5c68ad80b76f7bbac956ca16364088adf3d08f43..1ea3d064c913510ff1ada2be0c4206ba99ee5474 100644 (file)
--- a/fio.h
+++ b/fio.h
@@ -429,6 +429,7 @@ struct thread_data {
        FILE *io_log_rfile;
        unsigned int io_log_blktrace;
        unsigned int io_log_blktrace_swap;
+       unsigned long long io_log_blktrace_last_ttime;
        unsigned int io_log_current;
        unsigned int io_log_checkmark;
        unsigned int io_log_highmark;