[PATCH AUTOSEL 4.19 1/2] fs/file: fix the check in find_next_fd()

[PATCH AUTOSEL 4.19 1/2] fs/file: fix the check in find_next_fd()

[Sasha Levin]

From: Yuntao Wang <yuntao.wang@linux.dev>

[ Upstream commit ed8c7fbdfe117abbef81f65428ba263118ef298a ]

The maximum possible return value of find_next_zero_bit(fdt->full_fds_bits,
maxbit, bitbit) is maxbit. This return value, multiplied by BITS_PER_LONG,
gives the value of bitbit, which can never be greater than maxfd, it can
only be equal to maxfd at most, so the following check 'if (bitbit > maxfd)'
will never be true.

Moreover, when bitbit equals maxfd, it indicates that there are no unused
fds, and the function can directly return.

Fix this check.

Signed-off-by: Yuntao Wang <yuntao.wang@linux.dev>
Link: https://lore.kernel.org/r/20240529160656.209352-1-yuntao.wang@linux.dev
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index 928ba7b8df1e9..f5ba0e6f1a4c6 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -462,12 +462,12 @@ struct files_struct init_files = {
 
 static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start)
 {
-	unsigned int maxfd = fdt->max_fds;
+	unsigned int maxfd = fdt->max_fds; /* always multiple of BITS_PER_LONG */
 	unsigned int maxbit = maxfd / BITS_PER_LONG;
 	unsigned int bitbit = start / BITS_PER_LONG;
 
 	bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG;
-	if (bitbit > maxfd)
+	if (bitbit >= maxfd)
 		return maxfd;
 	if (bitbit > start)
 		start = bitbit;
-- 
2.43.0

[PATCH AUTOSEL 4.19 2/2] mei: demote client disconnect warning on suspend to debug

[Sasha Levin]

From: Alexander Usyskin <alexander.usyskin@intel.com>

[ Upstream commit 1db5322b7e6b58e1b304ce69a50e9dca798ca95b ]

Change level for the "not connected" client message in the write
callback from error to debug.

The MEI driver currently disconnects all clients upon system suspend.
This behavior is by design and user-space applications with
open connections before the suspend are expected to handle errors upon
resume, by reopening their handles, reconnecting,
and retrying their operations.

However, the current driver implementation logs an error message every
time a write operation is attempted on a disconnected client.
Since this is a normal and expected flow after system resume
logging this as an error can be misleading.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20240530091415.725247-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/misc/mei/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 87281b3695e60..e87c2b13c381e 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -271,7 +271,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 	}
 
 	if (!mei_cl_is_connected(cl)) {
-		cl_err(dev, cl, "is not connected");
+		cl_dbg(dev, cl, "is not connected");
 		rets = -ENODEV;
 		goto out;
 	}
-- 
2.43.0