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w1/masters/ds2490: queue up found IDs during scan

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Queue up found IDs in a buffer and run the callback once for each found ID
at the end. This is necessary because we hold the bus_mutex during the
whole scan, and some of the "add-device" callbacks deadlock as they
themselves want to mutex_lock(bus_mutex).

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Christian Vogel <vogelchr@vogel.cx>
Link: https://lore.kernel.org/r/20210113195018.7498-3-vogelchr@vogel.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christian Vogel
2021-01-13 20:50:18 +01:00
committed by Greg Kroah-Hartman
parent 48b7de6687
commit e3fe0e89fe
1 changed files with 20 additions and 5 deletions
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25
drivers/w1/masters/ds2490.c
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@@ -688,12 +688,22 @@ static void ds9490r_search(void *data, struct w1_master *master,
* packet size. * packet size.
*/ */
const size_t bufsize = 2 * 64; const size_t bufsize = 2 * 64;
u64 *buf; u64 *buf, *found_ids;
buf = kmalloc(bufsize, GFP_KERNEL); buf = kmalloc(bufsize, GFP_KERNEL);
if (!buf) if (!buf)
return; return;
/*
* We are holding the bus mutex during the scan, but adding devices via the
* callback needs the bus to be unlocked. So we queue up found ids here.
*/
found_ids = kmalloc_array(master->max_slave_count, sizeof(u64), GFP_KERNEL);
if (!found_ids) {
kfree(buf);
return;
}
mutex_lock(&master->bus_mutex); mutex_lock(&master->bus_mutex);
/* address to start searching at */ /* address to start searching at */
@@ -729,13 +739,13 @@ static void ds9490r_search(void *data, struct w1_master *master,
if (err < 0) if (err < 0)
break; break;
for (i = 0; i < err/8; ++i) { for (i = 0; i < err/8; ++i) {
++found; found_ids[found++] = buf[i];
if (found <= search_limit)
callback(master, buf[i]);
/* can't know if there will be a discrepancy /* can't know if there will be a discrepancy
* value after until the next id */ * value after until the next id */
if (found == search_limit) if (found == search_limit) {
master->search_id = buf[i]; master->search_id = buf[i];
break;
}
} }
} }
@@ -759,9 +769,14 @@ static void ds9490r_search(void *data, struct w1_master *master,
master->max_slave_count); master->max_slave_count);
set_bit(W1_WARN_MAX_COUNT, &master->flags); set_bit(W1_WARN_MAX_COUNT, &master->flags);
} }
search_out: search_out:
mutex_unlock(&master->bus_mutex); mutex_unlock(&master->bus_mutex);
kfree(buf); kfree(buf);
for (i = 0; i < found; i++) /* run callback for all queued up IDs */
callback(master, found_ids[i]);
kfree(found_ids);
} }
#if 0 #if 0