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firmware: arm_scmi: Fix timeout checks on polling path

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commit c23c03bf1faa1e76be1eba35bad6da6a2a7c95ee upstream.

Polling mode transactions wait for a reply busy-looping without holding a
spinlock, but currently the timeout checks are based only on elapsed time:
as a result we could hit a false positive whenever our busy-looping thread
is pre-empted and scheduled out for a time greater than the polling
timeout.

Change the checks at the end of the busy-loop to make sure that the polling
wasn't indeed successful or an out-of-order reply caused the polling to be
forcibly terminated.

Fixes: 31d2f803c1 ("firmware: arm_scmi: Add sync_cmds_completed_on_ret transport flag")
Reported-by: Huangjie <huangjie1663@phytium.com.cn>
Closes: https://lore.kernel.org/arm-scmi/20250123083323.2363749-1-jackhuang021@gmail.com/
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Cc: stable@vger.kernel.org # 5.18.x
Message-Id: <20250310175800.1444293-1-cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Cristian Marussi
2025-03-10 17:58:00 +00:00
committed by Greg Kroah-Hartman
parent fe3da1bfd8
commit 14ee85b748
1 changed files with 8 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/firmware/arm_scmi/driver.c
+8 -5
View File
@@ -1219,7 +1219,8 @@ static void xfer_put(const struct scmi_protocol_handle *ph,
} }
static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo, static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer, ktime_t stop) struct scmi_xfer *xfer, ktime_t stop,
bool *ooo)
{ {
struct scmi_info *info = handle_to_scmi_info(cinfo->handle); struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
@@ -1228,7 +1229,7 @@ static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo,
* in case of out-of-order receptions of delayed responses * in case of out-of-order receptions of delayed responses
*/ */
return info->desc->ops->poll_done(cinfo, xfer) || return info->desc->ops->poll_done(cinfo, xfer) ||
try_wait_for_completion(&xfer->done) || (*ooo = try_wait_for_completion(&xfer->done)) ||
ktime_after(ktime_get(), stop); ktime_after(ktime_get(), stop);
} }
@@ -1245,15 +1246,17 @@ static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
* itself to support synchronous commands replies. * itself to support synchronous commands replies.
*/ */
if (!desc->sync_cmds_completed_on_ret) { if (!desc->sync_cmds_completed_on_ret) {
bool ooo = false;
/* /*
* Poll on xfer using transport provided .poll_done(); * Poll on xfer using transport provided .poll_done();
* assumes no completion interrupt was available. * assumes no completion interrupt was available.
*/ */
ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms); ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms);
spin_until_cond(scmi_xfer_done_no_timeout(cinfo, spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer,
xfer, stop)); stop, &ooo));
if (ktime_after(ktime_get(), stop)) { if (!ooo && !info->desc->ops->poll_done(cinfo, xfer)) {
dev_err(dev, dev_err(dev,
"timed out in resp(caller: %pS) - polling\n", "timed out in resp(caller: %pS) - polling\n",
(void *)_RET_IP_); (void *)_RET_IP_);