linux-kernel - [PATCH] gpio: sim: quietly ignore configured lines outside the bank

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Message-Id: <20230607065004.37112-1-warthog618@gmail.com>
Date:   Wed,  7 Jun 2023 14:50:04 +0800
From:   Kent Gibson <warthog618@...il.com>
To:     linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
        brgl@...ev.pl, linus.walleij@...aro.org
Cc:     Kent Gibson <warthog618@...il.com>
Subject: [PATCH] gpio: sim: quietly ignore configured lines outside the bank

The user-space policy of the gpio-sim is that configuration for lines
with offsets outside the bounds of the corresponding bank is ignored,
but gpio-sim is still using that configuration when constructing the
sim.  In the case of named lines this results in temporarily allocating
space for names that are not used, and for hogs results in errors being
logged when the gpio-sim attempts to register the out of range hog with
gpiolib:

gpiochip_machine_hog: unable to get GPIO desc: -22

Add checks to filter out any line configuration outside the bounds
of the bank when constructing the sim.

Signed-off-by: Kent Gibson <warthog618@...il.com>
---

This is based on for-next patched with my recent memory corruption fix,
as it touches a bit of the same code.

Cheers,
Kent.

 drivers/gpio/gpio-sim.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index fab67a5785d7..8b49b0abacd5 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -696,6 +696,9 @@ static char **gpio_sim_make_line_names(struct gpio_sim_bank *bank,
 	char **line_names;
 
 	list_for_each_entry(line, &bank->line_list, siblings) {
+		if (line->offset >= bank->num_lines)
+			continue;
+
 		if (line->name) {
 			if (line->offset > max_offset)
 				max_offset = line->offset;
@@ -722,6 +725,9 @@ static char **gpio_sim_make_line_names(struct gpio_sim_bank *bank,
 		return ERR_PTR(-ENOMEM);
 
 	list_for_each_entry(line, &bank->line_list, siblings) {
+		if (line->offset >= bank->num_lines)
+			continue;
+
 		if (line->name && (line->offset <= max_offset))
 			line_names[line->offset] = line->name;
 	}
@@ -756,6 +762,9 @@ static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
 
 	list_for_each_entry(bank, &dev->bank_list, siblings) {
 		list_for_each_entry(line, &bank->line_list, siblings) {
+			if (line->offset >= bank->num_lines)
+				continue;
+
 			if (line->hog)
 				num_hogs++;
 		}
@@ -771,6 +780,9 @@ static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
 
 	list_for_each_entry(bank, &dev->bank_list, siblings) {
 		list_for_each_entry(line, &bank->line_list, siblings) {
+			if (line->offset >= bank->num_lines)
+				continue;
+
 			if (!line->hog)
 				continue;
 

base-commit: ba65c79fbb813423e7d42d99375e2045b27958a6
prerequisite-patch-id: d89da2e3b7511c5b8132a379b12e4996256ac214
-- 
2.40.1