[PATCH] SG io engine: better handling of multiple files

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/engines/sg.c b/engines/sg.c
index 862cd609b45f5870ed2d53e2ef9901feff75ae76..877264acd15b3316f4abd6b2c5002f09177f83df 100644 (file)
--- a/engines/sg.c
+++ b/engines/sg.c
@@ -60,44 +60,96 @@ static int fio_sgio_ioctl_getevents(struct thread_data *td, int fio_unused min,
        return 1;
 }
 
+static int pollin_events(struct pollfd *pfds, int fds)
+{
+       int i;
+
+       for (i = 0; i < fds; i++)
+               if (pfds[i].revents & POLLIN)
+                       return 1;
+
+       return 0;
+}
 
 static int fio_sgio_getevents(struct thread_data *td, int min, int max,
                              struct timespec fio_unused *t)
 {
+       /*
+        * normally hard coding &td->files[0] is a bug that needs to be fixed,
+        * but it's ok here as all files should point to the same device.
+        */
        struct fio_file *f = &td->files[0];
        struct sgio_data *sd = td->io_ops->data;
-       struct pollfd pfd = { .fd = f->fd, .events = POLLIN };
-       void *buf = malloc(max * sizeof(struct sg_io_hdr));
-       int left = max, ret, events, i, r = 0, fl = 0;
+       int left = max, ret, events, i, r = 0, *fl;
+       struct pollfd *pfds;
+       void *buf;
 
        /*
-        * don't block for !events
+        * Fill in the file descriptors
         */
-       if (!min) {
-               fl = fcntl(f->fd, F_GETFL);
-               fcntl(f->fd, F_SETFL, fl | O_NONBLOCK);
+       pfds = malloc(sizeof(struct pollfd) * td->nr_files);
+       fl = malloc(sizeof(int) * td->nr_files);
+
+       for_each_file(td, f, i) {
+               /*
+                * don't block for min events == 0
+                */
+               if (!min) {
+                       fl[i] = fcntl(f->fd, F_GETFL);
+                       fcntl(f->fd, F_SETFL, fl[i] | O_NONBLOCK);
+               }
+               pfds[i].fd = f->fd;
+               pfds[i].events = POLLIN;
        }
 
+       buf = malloc(max * sizeof(struct sg_io_hdr));
        while (left) {
+               void *p;
+
                do {
                        if (!min)
                                break;
-                       poll(&pfd, 1, -1);
-                       if (pfd.revents & POLLIN)
+
+                       ret = poll(pfds, td->nr_files, -1);
+                       if (ret < 0) {
+                               td_verror(td, errno);
+                               if (!r)
+                                       r = -1;
+                               break;
+                       } else if (!ret)
+                               continue;
+
+                       if (pollin_events(pfds, td->nr_files))
                                break;
                } while (1);
 
-               ret = read(f->fd, buf, left * sizeof(struct sg_io_hdr));
-               if (ret < 0) {
-                       if (errno == EAGAIN)
-                               break;
-                       td_verror(td, errno);
-                       r = -1;
+               if (r < 0)
                        break;
-               } else if (!ret)
+
+re_read:
+               p = buf;
+               events = 0;
+               for_each_file(td, f, i) {
+                       ret = read(f->fd, p, left * sizeof(struct sg_io_hdr));
+                       if (ret < 0) {
+                               if (errno == EAGAIN)
+                                       continue;
+                               td_verror(td, errno);
+                               r = -1;
+                               break;
+                       } else if (ret) {
+                               p += ret;
+                               events += ret / sizeof(struct sg_io_hdr);
+                       }
+               }
+
+               if (r < 0)
                        break;
+               if (!events) {
+                       usleep(1000);
+                       goto re_read;
+               }
 
-               events = ret / sizeof(struct sg_io_hdr);
                left -= events;
                r += events;
 
@@ -108,10 +160,14 @@ static int fio_sgio_getevents(struct thread_data *td, int min, int max,
                }
        }
 
-       if (!min)
-               fcntl(f->fd, F_SETFL, fl);
+       if (!min) {
+               for_each_file(td, f, i)
+                       fcntl(f->fd, F_SETFL, fl[i]);
+       }
 
        free(buf);
+       free(pfds);
+       free(fl);
        return r;
 }