Patch "i3c/master/mipi-i3c-hci: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    i3c/master/mipi-i3c-hci: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i3c-master-mipi-i3c-hci-fix-a-potentially-infinite-l.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8e9f8d8f0fb81cc6912cb8d858883799008074fd
Author: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
Date:   Wed Nov 17 23:05:23 2021 +0100

    i3c/master/mipi-i3c-hci: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
    
    [ Upstream commit 3f43926f271287fb1744c9ac9ae1122497f2b0c2 ]
    
    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@xxxxxxxxxx>
    Acked-by: Nicolas Pitre <npitre@xxxxxxxxxxxx>
    Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
    Link: https://lore.kernel.org/r/0cdf3cb10293ead1acd271fdb8a70369c298c082.1637186628.git.christophe.jaillet@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
index 783e551a2c85a..97bb49ff5b53b 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;