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Subject[PATCH v3] usb: gadget: f_mass_storage: call try_to_freeze only when its safe
Date
Call try_to_freeze() in sleep_thread() only when it's safe to sleep.
do_read() and do_write() calls sleep_thread with lock held.
Make sure these won't call try_to_freeze() by passing can_freeze flag
to sleep_thread.

Calling try_to_freeze() with a lock hold was done since day one in
f_mass_storage but since commit 0f9548ca1 ("lockdep: check that no
locks held at freeze time") lockdep complains about it.

Signed-off-by: George Cherian <george.cherian@ti.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
---
change from v1 -> v2
amend the commit log
v2 -> v3
amend the comit log again
drivers/usb/gadget/f_mass_storage.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index a03ba2c..f2d0d4b 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -602,13 +602,14 @@ static bool start_out_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
return true;
}

-static int sleep_thread(struct fsg_common *common)
+static int sleep_thread(struct fsg_common *common, bool can_freeze)
{
int rc = 0;

/* Wait until a signal arrives or we are woken up */
for (;;) {
- try_to_freeze();
+ if (can_freeze)
+ try_to_freeze();
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current)) {
rc = -EINTR;
@@ -682,7 +683,7 @@ static int do_read(struct fsg_common *common)
/* Wait for the next buffer to become available */
bh = common->next_buffhd_to_fill;
while (bh->state != BUF_STATE_EMPTY) {
- rc = sleep_thread(common);
+ rc = sleep_thread(common, false);
if (rc)
return rc;
}
@@ -937,7 +938,7 @@ static int do_write(struct fsg_common *common)
}

/* Wait for something to happen */
- rc = sleep_thread(common);
+ rc = sleep_thread(common, false);
if (rc)
return rc;
}
@@ -1504,7 +1505,7 @@ static int throw_away_data(struct fsg_common *common)
}

/* Otherwise wait for something to happen */
- rc = sleep_thread(common);
+ rc = sleep_thread(common, true);
if (rc)
return rc;
}
@@ -1625,7 +1626,7 @@ static int send_status(struct fsg_common *common)
/* Wait for the next buffer to become available */
bh = common->next_buffhd_to_fill;
while (bh->state != BUF_STATE_EMPTY) {
- rc = sleep_thread(common);
+ rc = sleep_thread(common, true);
if (rc)
return rc;
}
@@ -1828,7 +1829,7 @@ static int do_scsi_command(struct fsg_common *common)
bh = common->next_buffhd_to_fill;
common->next_buffhd_to_drain = bh;
while (bh->state != BUF_STATE_EMPTY) {
- rc = sleep_thread(common);
+ rc = sleep_thread(common, true);
if (rc)
return rc;
}
@@ -2174,7 +2175,7 @@ static int get_next_command(struct fsg_common *common)
/* Wait for the next buffer to become available */
bh = common->next_buffhd_to_fill;
while (bh->state != BUF_STATE_EMPTY) {
- rc = sleep_thread(common);
+ rc = sleep_thread(common, true);
if (rc)
return rc;
}
@@ -2193,7 +2194,7 @@ static int get_next_command(struct fsg_common *common)

/* Wait for the CBW to arrive */
while (bh->state != BUF_STATE_FULL) {
- rc = sleep_thread(common);
+ rc = sleep_thread(common, true);
if (rc)
return rc;
}
@@ -2379,7 +2380,7 @@ static void handle_exception(struct fsg_common *common)
}
if (num_active == 0)
break;
- if (sleep_thread(common))
+ if (sleep_thread(common, true))
return;
}

@@ -2516,7 +2517,7 @@ static int fsg_main_thread(void *common_)
}

if (!common->running) {
- sleep_thread(common);
+ sleep_thread(common, true);
continue;
}

--
1.8.1


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