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tcmu: remove commands_lock

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No need for the commands_lock. The cmdr_lock is already held during
idr addition and deletion, so just grab it during traversal.

Note: This also fixes a issue where we should have been using at
least _bh locking in tcmu_handle_completions when taking the commands
lock to prevent the case where tcmu_handle_completions could be
interrupted by a timer softirq while the commands_lock is held.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Mike Christie 2017-11-28 12:40:32 -06:00 committed by Nicholas Bellinger
parent 488ebe4c35
commit 6fddcb7754
1 changed files with 3 additions and 10 deletions
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13
drivers/target/target_core_user.c
View file

@ -139,7 +139,6 @@ struct tcmu_dev {
struct radix_tree_root data_blocks;
struct idr commands;
spinlock_t commands_lock;
struct timer_list timeout;
unsigned int cmd_time_out;
@ -1014,10 +1013,7 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
}
WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
spin_lock(&udev->commands_lock);
cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
spin_unlock(&udev->commands_lock);
if (!cmd) {
pr_err("cmd_id not found, ring is broken\n");
set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
@ -1115,7 +1111,6 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
INIT_LIST_HEAD(&udev->timedout_entry);
idr_init(&udev->commands);
spin_lock_init(&udev->commands_lock);
timer_setup(&udev->timeout, tcmu_device_timedout, 0);
@ -1333,16 +1328,14 @@ static void tcmu_dev_kref_release(struct kref *kref)
spin_unlock_bh(&timed_out_udevs_lock);
/* Upper layer should drain all requests before calling this */
spin_lock_irq(&udev->commands_lock);
mutex_lock(&udev->cmdr_lock);
idr_for_each_entry(&udev->commands, cmd, i) {
if (tcmu_check_and_free_pending_cmd(cmd) != 0)
all_expired = false;
}
idr_destroy(&udev->commands);
spin_unlock_irq(&udev->commands_lock);
WARN_ON(!all_expired);
mutex_lock(&udev->cmdr_lock);
tcmu_blocks_release(&udev->data_blocks, 0, udev->dbi_max + 1);
mutex_unlock(&udev->cmdr_lock);
@ -2060,9 +2053,9 @@ static void check_timedout_devices(void)
list_del_init(&udev->timedout_entry);
spin_unlock_bh(&timed_out_udevs_lock);
spin_lock(&udev->commands_lock);
mutex_lock(&udev->cmdr_lock);
idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
spin_unlock(&udev->commands_lock);
mutex_unlock(&udev->cmdr_lock);
spin_lock_bh(&timed_out_udevs_lock);
}