net/mlx5: Allow async trigger completion execution on single CPU systems

[ Upstream commit 2808b37b59288ad8f1897e3546c2296df3384b65 ]

For a single CPU system, the kernel thread executing mlx5_cmd_flush()
never releases the CPU but calls down_trylock(&cmd→sem) in a busy loop.
On a single processor system, this leads to a deadlock as the kernel
thread which executes mlx5_cmd_invoke() never gets scheduled. Fix this,
by adding the cond_resched() call to the loop, allow the command
completion kernel thread to execute.

Fixes: 8e715cd613a1 ("net/mlx5: Set command entry semaphore up once got index free")
Signed-off-by: Alexander Schmidt <alexschm@de.ibm.com>
Signed-off-by: Roy Novich <royno@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Roy Novich 2022-11-02 23:55:38 -07:00 committed by Greg Kroah-Hartman
parent 5b72cf7a40
commit 3892c2d335

View File

@ -1682,12 +1682,17 @@ void mlx5_cmd_flush(struct mlx5_core_dev *dev)
struct mlx5_cmd *cmd = &dev->cmd;
int i;
for (i = 0; i < cmd->max_reg_cmds; i++)
while (down_trylock(&cmd->sem))
for (i = 0; i < cmd->max_reg_cmds; i++) {
while (down_trylock(&cmd->sem)) {
mlx5_cmd_trigger_completions(dev);
cond_resched();
}
}
while (down_trylock(&cmd->pages_sem))
while (down_trylock(&cmd->pages_sem)) {
mlx5_cmd_trigger_completions(dev);
cond_resched();
}
/* Unlock cmdif */
up(&cmd->pages_sem);