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From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: alexandre.belloni@bootlin.com, npitre@baylibre.com,
	boris.brezillon@collabora.com
Cc: linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Subject: [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
Date: Wed, 17 Nov 2021 23:05:23 +0100	[thread overview]
Message-ID: <0cdf3cb10293ead1acd271fdb8a70369c298c082.1637186628.git.christophe.jaillet@wanadoo.fr> (raw)

The code in 'hci_dat_v1_get_index()' really looks like a hand coded version
of 'for_each_set_bit()', except that a +1 is missing when searching for the
next set bit.

This really looks odd and it seems that it will loop until 'dat_w0_read()'
returns the expected result.

So use 'for_each_set_bit()' instead. It is less verbose and should be more
correct.

Fixes: 9ad9a52cce28 ("i3c/master: introduce the mipi-i3c-hci driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Speculative fix. Untested.
---
 drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
index 783e551a2c85..97bb49ff5b53 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
@@ -160,9 +160,7 @@ static int hci_dat_v1_get_index(struct i3c_hci *hci, u8 dev_addr)
 	unsigned int dat_idx;
 	u32 dat_w0;
 
-	for (dat_idx = find_first_bit(hci->DAT_data, hci->DAT_entries);
-	     dat_idx < hci->DAT_entries;
-	     dat_idx = find_next_bit(hci->DAT_data, hci->DAT_entries, dat_idx)) {
+	for_each_set_bit(dat_idx, hci->DAT_data, hci->DAT_entries) {
 		dat_w0 = dat_w0_read(dat_idx);
 		if (FIELD_GET(DAT_0_DYNAMIC_ADDRESS, dat_w0) == dev_addr)
 			return dat_idx;
-- 
2.30.2


WARNING: multiple messages have this Message-ID (diff)
From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: alexandre.belloni@bootlin.com, npitre@baylibre.com,
	boris.brezillon@collabora.com
Cc: linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Subject: [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
Date: Wed, 17 Nov 2021 23:05:23 +0100	[thread overview]
Message-ID: <0cdf3cb10293ead1acd271fdb8a70369c298c082.1637186628.git.christophe.jaillet@wanadoo.fr> (raw)

The code in 'hci_dat_v1_get_index()' really looks like a hand coded version
of 'for_each_set_bit()', except that a +1 is missing when searching for the
next set bit.

This really looks odd and it seems that it will loop until 'dat_w0_read()'
returns the expected result.

So use 'for_each_set_bit()' instead. It is less verbose and should be more
correct.

Fixes: 9ad9a52cce28 ("i3c/master: introduce the mipi-i3c-hci driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Speculative fix. Untested.
---
 drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
index 783e551a2c85..97bb49ff5b53 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
@@ -160,9 +160,7 @@ static int hci_dat_v1_get_index(struct i3c_hci *hci, u8 dev_addr)
 	unsigned int dat_idx;
 	u32 dat_w0;
 
-	for (dat_idx = find_first_bit(hci->DAT_data, hci->DAT_entries);
-	     dat_idx < hci->DAT_entries;
-	     dat_idx = find_next_bit(hci->DAT_data, hci->DAT_entries, dat_idx)) {
+	for_each_set_bit(dat_idx, hci->DAT_data, hci->DAT_entries) {
 		dat_w0 = dat_w0_read(dat_idx);
 		if (FIELD_GET(DAT_0_DYNAMIC_ADDRESS, dat_w0) == dev_addr)
 			return dat_idx;
-- 
2.30.2


-- 
linux-i3c mailing list
linux-i3c@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-i3c

             reply	other threads:[~2021-11-17 22:05 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17 22:05 Christophe JAILLET [this message]
2021-11-17 22:05 ` [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()' Christophe JAILLET
2021-11-19 23:16 ` Nicolas Pitre
2021-11-19 23:16   ` Nicolas Pitre
2021-12-10 15:39 ` Alexandre Belloni
2021-12-10 15:39   ` Alexandre Belloni

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