New function: sysfs_wait

We have several places that wait for activity on a sysfs
file.  Combine most of these into a single 'sysfs_wait' function.

Signed-off-by: NeilBrown <neilb@suse.de>

Grow.c

@@ -626,13 +626,9 @@ static void wait_reshape(struct mdinfo *sra)
 	if (fd < 0)
 		return;
 
-	while  (sysfs_fd_get_str(fd, action, 20) > 0 &&
-		strncmp(action, "reshape", 7) == 0) {
-		fd_set rfds;
-		FD_ZERO(&rfds);
-		FD_SET(fd, &rfds);
-		select(fd+1, NULL, NULL, &rfds, NULL);
-	}
+	while (sysfs_fd_get_str(fd, action, 20) > 0 &&
+	       strncmp(action, "reshape", 7) == 0)
+		sysfs_wait(fd, NULL);
 	close(fd);
 }
 
@@ -3777,7 +3773,6 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
 		 * waiting forever on a dead array
 		 */
 		char action[20];
-		fd_set rfds;
 		if (sysfs_get_str(info, NULL, "sync_action",
 				  action, 20) <= 0 ||
 		    strncmp(action, "reshape", 7) != 0)
@@ -3793,9 +3788,7 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
 		    && info->reshape_progress < (info->component_size
 						 * reshape->after.data_disks))
 			break;
-		FD_ZERO(&rfds);
-		FD_SET(fd, &rfds);
-		select(fd+1, NULL, NULL, &rfds, NULL);
+		sysfs_wait(fd, NULL);
 		if (sysfs_fd_get_ll(fd, &completed) < 0)
 			goto check_progress;
 	}
@@ -3840,15 +3833,10 @@ check_progress:
 		/* The abort might only be temporary.  Wait up to 10
 		 * seconds for fd to contain a valid number again.
 		 */
-		struct timeval tv;
+		int wait = 10000;
 		int rv = -2;
-		tv.tv_sec = 10;
-		tv.tv_usec = 0;
-		while (fd >= 0 && rv < 0 && tv.tv_sec > 0) {
-			fd_set rfds;
-			FD_ZERO(&rfds);
-			FD_SET(fd, &rfds);
-			if (select(fd+1, NULL, NULL, &rfds, &tv) != 1)
+		while (fd >= 0 && rv < 0 && wait > 0) {
+			if (sysfs_wait(fd, &wait) != 1)
 				break;
 			switch (sysfs_fd_get_ll(fd, &completed)) {
 			case 0:
@@ -3856,7 +3844,7 @@ check_progress:
 				rv = 1;
 				break;
 			case -2: /* read error - abort */
-				tv.tv_sec = 0;
+				wait = 0;
 				break;
 			}
 		}

Monitor.c

@@ -1050,17 +1050,12 @@ int WaitClean(char *dev, int sock, int verbose)
 	if (rv) {
 		int state_fd = sysfs_open(fd2devnm(fd), NULL, "array_state");
 		char buf[20];
-		fd_set fds;
-		struct timeval tm;
+		int delay = 5000;
 
 		/* minimize the safe_mode_delay and prepare to wait up to 5s
 		 * for writes to quiesce
 		 */
 		sysfs_set_safemode(mdi, 1);
-		tm.tv_sec = 5;
-		tm.tv_usec = 0;
-
-		FD_ZERO(&fds);
 
 		/* wait for array_state to be clean */
 		while (1) {
@@ -1069,8 +1064,7 @@ int WaitClean(char *dev, int sock, int verbose)
 				break;
 			if (sysfs_match_word(buf, clean_states) <= 4)
 				break;
-			FD_SET(state_fd, &fds);
-			rv = select(state_fd + 1, NULL, NULL, &fds, &tm);
+			rv = sysfs_wait(state_fd, &delay);
 			if (rv < 0 && errno != EINTR)
 				break;
 			lseek(state_fd, 0, SEEK_SET);

mdadm.h

@@ -549,6 +549,7 @@ extern int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume);
 extern int sysfs_disk_to_scsi_id(int fd, __u32 *id);
 extern int sysfs_unique_holder(char *devnm, long rdev);
 extern int sysfs_freeze_array(struct mdinfo *sra);
+extern int sysfs_wait(int fd, int *msec);
 extern int load_sys(char *path, char *buf);
 extern int reshape_prepare_fdlist(char *devname,
 				  struct mdinfo *sra,

super-intel.c

@@ -10163,10 +10163,7 @@ int wait_for_reshape_imsm(struct mdinfo *sra, int ndata)
 
 	do {
 		char action[20];
-		fd_set rfds;
-		FD_ZERO(&rfds);
-		FD_SET(fd, &rfds);
-		select(fd+1, &rfds, NULL, NULL, NULL);
+		sysfs_wait(fd, NULL);
 		if (sysfs_get_str(sra, NULL, "sync_action",
 				  action, 20) > 0 &&
 				strncmp(action, "reshape", 7) != 0)

sysfs.c

@@ -844,3 +844,32 @@ int sysfs_freeze_array(struct mdinfo *sra)
 		return 0;
 	return 1;
 }
+
+int sysfs_wait(int fd, int *msec)
+{
+	/* Wait up to '*msec' for fd to have an exception condition.
+	 * if msec == NULL, wait indefinitely.
+	 */
+	fd_set fds;
+	int n;
+	FD_ZERO(&fds);
+	FD_SET(fd, &fds);
+	if (msec == NULL)
+		n = select(fd+1, NULL, NULL, &fds, NULL);
+	else if (*msec < 0)
+		n = 0;
+	else {
+		struct timeval start, end, tv;
+		gettimeofday(&start, NULL);
+		if (*msec < 1000)
+			tv.tv_usec = (*msec)*1000;
+		else
+			tv.tv_sec = (*msec)/1000;
+		n = select(fd+1, NULL, NULL, &fds, &tv);
+		gettimeofday(&end, NULL);
+		end.tv_sec -= start.tv_sec;
+		*msec -= (end.tv_sec * 1000 + end.tv_usec/1000
+			  - start.tv_usec/100) + 1;
+	}
+	return n;
+}