For some devices, updating the flash can take significant time during
operations where no status can meaningfully be reported. This can be
somewhat confusing to a user who sees devlink appear to hang on the
terminal waiting for the device to update.

Provide a ticking counter of the time elapsed since the previous status
message in order to make it clear that the program is not simply stuck.

Do not display this message unless a few seconds have passed since the
last status update. Additionally, if the previous status notification
included a timeout, display this as part of the message. If we do not
receive an error or a new status without that time out, replace it with
the text "timeout reached".

Signed-off-by: Jacob Keller <[email protected]>
---

Sending this as an RFC because I doubt this is the best implementation. For
one, I get a weird display issue where the cursor doesn't always end up on
the end of line in my shell.. The % display works properly, so I'm not sure
what's wrong here.

Second, even though select should be timing out every 1/10th of a second for
screen updates, I don't seem to get that behavior in my test. It takes about
8 to 10 seconds for the first elapsed time message to be displayed, and it
updates really slowly. Is select just not that precise? I even tried using a
timeout of zero, but this means we refresh way too often and it looks bad. I
am not sure what is wrong here...

 devlink/devlink.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 88 insertions(+), 1 deletion(-)

diff --git a/devlink/devlink.c b/devlink/devlink.c
index 0374175eda3d..7fb4b5ef1ebe 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -33,6 +33,7 @@
 #include <sys/select.h>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <sys/time.h>
 #include <rt_names.h>
 
 #include "version.h"
@@ -3066,6 +3067,9 @@ static int cmd_dev_info(struct dl *dl)
 
 struct cmd_dev_flash_status_ctx {
        struct dl *dl;
+       struct timeval last_status_msg;
+       char timeout_msg[128];
+       uint64_t timeout;
        char *last_msg;
        char *last_component;
        uint8_t not_first:1,
@@ -3083,6 +3087,14 @@ static int nullstrcmp(const char *str1, const char *str2)
        return str1 ? 1 : -1;
 }
 
+static void cmd_dev_flash_clear_elapsed_time(struct cmd_dev_flash_status_ctx 
*ctx)
+{
+       int i;
+
+       for (i = 0; i < strlen(ctx->timeout_msg); i++)
+               pr_out_tty("\b");
+}
+
 static int cmd_dev_flash_status_cb(const struct nlmsghdr *nlh, void *data)
 {
        struct cmd_dev_flash_status_ctx *ctx = data;
@@ -3116,6 +3128,11 @@ static int cmd_dev_flash_status_cb(const struct nlmsghdr 
*nlh, void *data)
                return MNL_CB_STOP;
        }
 
+       cmd_dev_flash_clear_elapsed_time(ctx);
+       gettimeofday(&ctx->last_status_msg, NULL);
+       ctx->timeout_msg[0] = '\0';
+       ctx->timeout = 0;
+
        if (tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_MSG])
                msg = 
mnl_attr_get_str(tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_MSG]);
        if (tb[DEVLINK_ATTR_FLASH_UPDATE_COMPONENT])
@@ -3124,6 +3141,8 @@ static int cmd_dev_flash_status_cb(const struct nlmsghdr 
*nlh, void *data)
                done = 
mnl_attr_get_u64(tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_DONE]);
        if (tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_TOTAL])
                total = 
mnl_attr_get_u64(tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_TOTAL]);
+       if (tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_TIMEOUT])
+               ctx->timeout = 
mnl_attr_get_u64(tb[DEVLINK_ATTR_FLASH_UPDATE_STATUS_TIMEOUT]);
 
        if (!nullstrcmp(msg, ctx->last_msg) &&
            !nullstrcmp(component, ctx->last_component) &&
@@ -3155,11 +3174,66 @@ static int cmd_dev_flash_status_cb(const struct 
nlmsghdr *nlh, void *data)
        return MNL_CB_STOP;
 }
 
+static void cmd_dev_flash_time_elapsed(struct cmd_dev_flash_status_ctx *ctx)
+{
+       struct timeval now, res;
+
+       gettimeofday(&now, NULL);
+       timersub(&now, &ctx->last_status_msg, &res);
+
+       /* Don't start displaying a timeout message until we've elapsed a few
+        * seconds...
+        */
+       if (res.tv_sec > 3) {
+               uint elapsed_m, elapsed_s;
+
+               /* clear the last elapsed time message, if we have one */
+               cmd_dev_flash_clear_elapsed_time(ctx);
+
+               elapsed_m = res.tv_sec / 60;
+               elapsed_s = res.tv_sec % 60;
+
+               /**
+                * If we've elapsed a few seconds without receiving any status
+                * notification from the device, we display a time elapsed
+                * message. This has a few possible formats:
+                *
+                * 1) just time elapsed, when no timeout was provided
+                *    " ( Xm Ys )"
+                * 2) time elapsed out of a timeout that came from the device
+                *    driver via DEVLINK_CMD_FLASH_UPDATE_STATUS_TIMEOUT
+                *    " ( Xm Ys : Am Ys)"
+                * 3) time elapsed if we still receive no status after
+                *    reaching the provided timeout.
+                *    " ( Xm Ys : timeout reached )"
+                */
+               if (!ctx->timeout) {
+                       snprintf(ctx->timeout_msg, sizeof(ctx->timeout_msg),
+                                " ( %um %us )", elapsed_m, elapsed_s);
+               } else if (res.tv_sec <= ctx->timeout) {
+                       uint timeout_m, timeout_s;
+
+                       timeout_m = ctx->timeout / 60;
+                       timeout_s = ctx->timeout % 60;
+
+                       snprintf(ctx->timeout_msg, sizeof(ctx->timeout_msg),
+                                " ( %um %us : %um %us )",
+                                elapsed_m, elapsed_s, timeout_m, timeout_s);
+               } else {
+                       snprintf(ctx->timeout_msg, sizeof(ctx->timeout_msg),
+                                " ( %um %us : timeout reached )", elapsed_m, 
elapsed_s);
+               }
+
+               pr_out_tty("%s", ctx->timeout_msg);
+       }
+}
+
 static int cmd_dev_flash_fds_process(struct cmd_dev_flash_status_ctx *ctx,
                                     struct mnlg_socket *nlg_ntf,
                                     int pipe_r)
 {
        int nlfd = mnlg_socket_get_fd(nlg_ntf);
+       struct timeval timeout;
        fd_set fds[3];
        int fdmax;
        int i;
@@ -3174,7 +3248,14 @@ static int cmd_dev_flash_fds_process(struct 
cmd_dev_flash_status_ctx *ctx,
        if (nlfd >= fdmax)
                fdmax = nlfd + 1;
 
-       while (select(fdmax, &fds[0], &fds[1], &fds[2], NULL) < 0) {
+       /* select only for a short while (1/20th of a second) in order to
+        * allow periodically updating the screen with an elapsed time
+        * indicator.
+        */
+       timeout.tv_sec = 0;
+       timeout.tv_usec = 100000;
+
+       while (select(fdmax, &fds[0], &fds[1], &fds[2], &timeout) < 0) {
                if (errno == EINTR)
                        continue;
                pr_err("select() failed\n");
@@ -3196,6 +3277,7 @@ static int cmd_dev_flash_fds_process(struct 
cmd_dev_flash_status_ctx *ctx,
                        return err2;
                ctx->flash_done = 1;
        }
+       cmd_dev_flash_time_elapsed(ctx);
        return 0;
 }
 
@@ -3256,6 +3338,11 @@ static int cmd_dev_flash(struct dl *dl)
        }
        close(pipe_w);
 
+       /* initialize starting time to allow comparison for when to begin
+        * displaying a time elapsed message.
+        */
+       gettimeofday(&ctx.last_status_msg, NULL);
+
        do {
                err = cmd_dev_flash_fds_process(&ctx, nlg_ntf, pipe_r);
                if (err)

base-commit: b8663da04939dd5de223ca0de23e466ce0a372f7
-- 
2.28.0.497.g54e85e7af1ac

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